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Rezaei M, Nezamzadeh-Ejhieh A, Massah AR. A Comprehensive Review on the Boosted Effects of Anion Vacancy in the Heterogeneous Photocatalytic Degradation, Part II: Focus on Oxygen Vacancy. ACS OMEGA 2024; 9:6093-6127. [PMID: 38371849 PMCID: PMC10870278 DOI: 10.1021/acsomega.3c07560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 02/20/2024]
Abstract
Environmental problems, including the increasingly polluted water and the energy crisis, have led to a need to propose novel strategies/methodologies to contribute to sustainable progress and enhance human well-being. For these goals, heterogeneous semiconducting-based photocatalysis is introduced as a green, eco-friendly, cost-effective, and effective strategy. The introduction of anion vacancies in semiconductors has been well-known as an effective strategy for considerably enhancing the photocatalytic activity of such photocatalytic systems, giving them the advantages of promoting light harvesting, facilitating photogenerated electron-hole pair separation, optimizing the electronic structure, and enhancing the yield of reactive radicals. This Review will introduce the effects of anion vacancy-dominated photodegradation systems. Then, their mechanism will illustrate how an anion vacancy changes the photodegradation pathway to enhance the degradation efficiency toward pollutants and the overall photocatalytic performance. Specifically, the vacancy defect types and the methods of tailoring vacancies will be briefly illustrated, and this part of the Review will focus on the oxygen vacancy (OV) and its recent advances. The challenges and development issues for engineered vacancy defects in photocatalysts will also be discussed for practical applications and to provide a promising research direction. Finally, some prospects for this emerging field will be proposed and suggested. All permission numbers for adopted figures from the literature are summarized in a separate file for the Editor.
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Affiliation(s)
- Mahdieh Rezaei
- Department
of Chemistry, Shahreza Branch, Islamic Azad
University, P.O. Box 311-86145, Shahreza, Isfahan 86139-74183, Iran
| | - Alireza Nezamzadeh-Ejhieh
- Department
of Chemistry, Shahreza Branch, Islamic Azad
University, P.O. Box 311-86145, Shahreza, Isfahan 86139-74183, Iran
- Department
of Chemistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Isfahan 81551-39998, Iran
| | - Ahmad Reza Massah
- Department
of Chemistry, Shahreza Branch, Islamic Azad
University, P.O. Box 311-86145, Shahreza, Isfahan 86139-74183, Iran
- Department
of Chemistry, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Isfahan 81551-39998, Iran
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2
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Feng L, Wang F, Luo H, Xu Z, Zhao T, Zhu J, Qin Y. Thermal vacuum de-oxygen fabrication of new catalytic pigments: SiO 2@TiO 2-x amorphous photonic crystals for formaldehyde removal. J Mater Chem B 2023; 11:1533-1544. [PMID: 36689209 DOI: 10.1039/d2tb02209e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Eliminating benzene and formaldehyde pollution is indispensable after the popularity of colorful home decoration in current society. The possibility and advantages of vividly colorful amorphous photonic crystals (APCs) as catalytic pigments were established. Biomimetic synthesis of APCs is an effective approach to obtaining angle-independent structural colors. Herein, we introduce oxygen vacancies through thermal vacuum de-oxygenation to synthesize SiO2@TiO2-x APCs for angle-independent structural colors and enhanced photocatalytic performance in one step. Core-shell nanospheres with controllable particle size were synthesized using a mixed-solvent method as the structural unit of APCs to prepare seven structural colors: red, orange, yellow, green, cyan, blue, and purple. The photocatalytic activity of in situ fabricated SiO2@TiO2-x APCs was conspicuously enhanced by thermal vacuum deoxidation. An amorphous layer formed on the TiO2 nanocrystals provides TiO2-x with excellent spectral response to visible light, transient photocurrent, and surface photovoltage up to 38.44 μA cm-2 and 28.8 mV, respectively. Black TiO2-x absorbs incoherent scattering, causing APCs to generate vividly angle-independent structural colors. The existence of oxygen vacancies in TiO2-x promotes electron activation and a synergistic effect with the photonic local effect of APCs in improving the degradation of formaldehyde by catalytic pigments, effectively protecting the beautiful living environment of human beings.
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Affiliation(s)
- Li Feng
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
| | - Fen Wang
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
| | - Hongjie Luo
- School of Materials Science and Engineering, Shanghai University, Shanghai 200444, People's Republic of China
| | - Ze Xu
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
| | - Ting Zhao
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
| | - Jianfeng Zhu
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
| | - Yi Qin
- School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China.
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3
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Chen S, Hu YH. Color TiO 2 Materials as Emerging Catalysts for Visible-NIR Light Photocatalysis, A Review. CATALYSIS REVIEWS 2023. [DOI: 10.1080/01614940.2023.2169451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Shaoqin Chen
- Department of Materials Science and Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Yun Hang Hu
- Department of Materials Science and Engineering, Michigan Technological University, Houghton, Michigan, USA
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4
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Is Black Titania a Promising Photocatalyst? Catalysts 2022. [DOI: 10.3390/catal12111320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Five different (commercial and self-synthesized) titania samples were mixed with NaBH4 and then heated to obtain black titania samples. The change in synthesis conditions resulted in the preparation of nine different photocatalysts, most of which were black in color. The photocatalysts were characterized by various methods, including X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), photoacoustic and reverse-double beam photoacoustic spectroscopy (PAS/RDB-PAS). The photocatalytic activity was tested for oxidative decomposition of acetic acid, methanol dehydrogenation, phenol degradation and bacteria inactivation (Escherichia coli) under different conditions, i.e., irradiation with UV, vis, and NIR, and in the dark. It was found that the properties of the obtained samples depended on the features of the original titania materials. A shift in XRD peaks was observed only in the case of the commercial titania samples, indicating self-doping, whereas faceted anatase samples (self-synthesized) showed high resistance towards bulk modification. Independent of the type and degree of modification, all modified samples exhibited much worse activity under UV irradiation than original titania photocatalysts both under aerobic and anaerobic conditions. It is proposed that the strong reduction conditions during the samples’ preparation resulted in the partial destruction of the titania surface, as evidenced by both microscopic observation and crystallographic data (an increase in amorphous content), and thus the formation of deep electron traps (bulk defects as oxygen vacancies) increasing the charge carriers’ recombination. Under vis irradiation, a slight increase in photocatalytic performance (phenol degradation) was obtained for only four samples, while two samples also exhibited slight activity under NIR. In the case of bacteria inactivation, some modified samples exhibited higher activity under both vis and NIR than respective pristine titania, which could be useful for disinfection, cancer treatment and other purposes. However, considering the overall performance of the black titania samples in this study, it is difficult to recommend them for broad environmental applications.
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5
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Sabinas-Hernández SA, Gracia Jiménez JM, Silva González NR, Elizalde-González MP, Salazar-Kuri U, Tehuacanero-Cuapa S. Blue Titania: The Outcome of Defects, Crystalline-Disordered Core-Shell Structure, and Hydrophilicity Change. NANOMATERIALS 2022; 12:nano12091501. [PMID: 35564210 PMCID: PMC9104741 DOI: 10.3390/nano12091501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/05/2022] [Accepted: 04/24/2022] [Indexed: 02/05/2023]
Abstract
In this research, changes in several characteristics of partially reduced titania were studied. The reduction process used made it possible to gradually observe changes in the material depending on the amount of reducing agent used. We used NaBH4 to impregnate commercial TiO2 with isopropyl alcohol. Impregnated TiO2 nanoparticles were dried and thermally treated in a nitrogen flow to obtain blue titania samples. Thorough spectroscopic characterization showed that oxygen atoms from hydroxyl groups, as well as from the surface, and the lattice of TiO2 was consumed. This caused changes in the surface and even in the bulk of TiO2 when the amount of reducing agent used was increased. Structural, optical, superficial, and textural characteristics were studied using XRD, Raman, DRS UV-Vis-NIR, Mid-DRIFT, XPS, and nitrogen adsorption/desorption isotherms. A photocatalytic test of the degradation of methylene blue dye was performed. Among different effects on the mentioned characteristics, we found evidence of changes in the surface properties of the blue titania samples and their probable effect on the photocatalytic properties. The reduction process implied a preponderant decrease in the surface hydrophilicity of the reduced samples, an effect shown for the first time in this type of material.
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Affiliation(s)
- Sergio A. Sabinas-Hernández
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Blvd. 18 Sur, Col. San Manuel, Ciudad Universitaria, Apartado Postal J-48, Puebla 72570, Mexico; (J.M.G.J.); (N.R.S.G.); (U.S.-K.)
- Correspondence:
| | - Justo Miguel Gracia Jiménez
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Blvd. 18 Sur, Col. San Manuel, Ciudad Universitaria, Apartado Postal J-48, Puebla 72570, Mexico; (J.M.G.J.); (N.R.S.G.); (U.S.-K.)
| | - Nicolás Rutilo Silva González
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Blvd. 18 Sur, Col. San Manuel, Ciudad Universitaria, Apartado Postal J-48, Puebla 72570, Mexico; (J.M.G.J.); (N.R.S.G.); (U.S.-K.)
| | - María P. Elizalde-González
- Centro de Química, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla, Ciudad Universitaria, Edif. IC7, Puebla 72570, Mexico;
| | - Ulises Salazar-Kuri
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Av. San Claudio y Blvd. 18 Sur, Col. San Manuel, Ciudad Universitaria, Apartado Postal J-48, Puebla 72570, Mexico; (J.M.G.J.); (N.R.S.G.); (U.S.-K.)
| | - Samuel Tehuacanero-Cuapa
- Instituto de Física, Universidad Nacional Autónoma de México, Circuito de la Investigación s/n, Ciudad Universitaria, Ciudad de México 04510, Mexico;
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6
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Feng L, Luo H, Wang F, Zhao T, Wei X, Zhu J, Qin Y. The Development of New Catalytic Pigments Based on SiO 2 Amorphous Photonic Crystals via Adding of Dual-Functional Black TiO 2-x Nanoparticles. ACS OMEGA 2022; 7:12089-12097. [PMID: 35449915 PMCID: PMC9016863 DOI: 10.1021/acsomega.2c00346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/17/2022] [Indexed: 06/14/2023]
Abstract
Biomimetic synthesis of amorphous photonic crystals (APCs) is an effective approach to obtaining non-iridescent structural colors. However, the structural colors of artificially prepared APCs are dim or even white due to the influence of incoherent scattering. In this paper, we present a novel method to combine APCs with black TiO2-x to construct a noniridescent structural color pigments with high visibility and photocatalytic activity. Due to the absorption of incoherently scattered light by black TiO2-x , the color saturation of structural colors has been significantly increased. In addition, the utilization rate of photogenic carriers was effectively enhanced by the slow light effect generated from the pseudoband gap of SiO2 APCs with TiO2-x absorbed full spectrum. The tone and color saturation of catalytic pigments is controlled by the diameter of SiO2 nanospheres and the ratio of TiO2-x nanoparticles, which provides a controllable application study in color-related fields as artwork, environmental coatings, and textiles.
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Affiliation(s)
- Li Feng
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
| | - Hongjie Luo
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
- School
of Materials Science and Engineering, Shanghai
University, Shanghai 200444, China
| | - Fen Wang
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
| | - Ting Zhao
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
| | - Xiaohong Wei
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
| | - Jianfeng Zhu
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
| | - Yi Qin
- Shaanxi
Key Laboratory of Green Preparation and Functionalization for Inorganic
Materials, School of Materials Science and Engineering, Shaanxi University of Science and Technology, Xian, Shaanxi 710021, China
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7
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Hydrogenated Amorphous Titania with Engineered Surface Oxygen Vacancy for Efficient Formaldehyde and Dye Removals under Visible-Light Irradiation. NANOMATERIALS 2022; 12:nano12050742. [PMID: 35269228 PMCID: PMC8911576 DOI: 10.3390/nano12050742] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 01/19/2023]
Abstract
Hydrogenated crystalized TiO2−x with oxygen vacant (OV) doping has attracted considerable attraction, owing to its impressive photoactivity. However, amorphous TiO2, as a common allotrope of titania, is ignored as a hydrogenated templet. In this work, hydrogenated amorphous TiO2−x (HAm-TiO2−x) with engineered surface OV and high surface area (176.7 cm2 g−1) was first prepared using a unique liquid plasma hydrogenation strategy. In HAm-TiO2−x, we found that OV was energetically retained in the subsurface region; in particular, the subsurface OV-induced energy level preferred to remain under the conduction band (0.5 eV) to form a conduction band tail and deep trap states, resulting in a narrow bandgap (2.36 eV). With the benefits of abundant light absorption and efficient photocarrier transportation, HAm-TiO2−x coated glass has demonstrated superior visible-light-driven self-cleaning performances. To investigate its formaldehyde photodegradation under harsh indoor conditions, HAm-TiO2−x was used to decompose low-concentration formaldehyde (~0.6 ppm) with weak-visible light (λ = 600 nm, power density = 0.136 mW/cm2). Thus, HAm-TiO2−x achieved high quantum efficiency of 3 × 10−6 molecules/photon and photoactivity of 92.6%. The adsorption capabilities of O2 (−1.42 eV) and HCHO (−1.58 eV) in HAm-TiO2−x are both largely promoted in the presence of subsurface OV. The surface reaction pathway and formaldehyde decomposition mechanism over HAm-TiO2−x were finally clarified. This work opened a promising way to fabricate hydrogenated amorphous photocatalysts, which could contribute to visible-light-driven photocatalytic environmental applications.
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8
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Yamazaki Y, Toyonaga T, Doshita N, Mori K, Kuwahara Y, Yamazaki S, Yamashita H. Crystal Facet Engineering and Hydrogen Spillover-Assisted Synthesis of Defective Pt/TiO 2-x Nanorods with Enhanced Visible Light-Driven Photocatalytic Activity. ACS APPLIED MATERIALS & INTERFACES 2022; 14:2291-2300. [PMID: 34967219 DOI: 10.1021/acsami.1c20148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Hydrogen spillover can assist the introduction of defects such as Ti3+ and concomitant oxygen vacancies (VO) in a TiO2 crystal, thereby inducing a new level below the conduction band to improve the conductivity of photogenerated electrons and the visible light absorption property of TiO2. Meanwhile, crystal facet engineering offers a promising approach to achieve improved activity by influencing the recombination step of the photogenerated electrons and holes. In this study, with the aim of achieving enhanced visible light-driven photocatalytic activity, rutile TiO2 nanorods with different aspect ratios were synthesized by crystal facet engineering, and Pt-deposited TiO2-x nanorods (Pt/TNR) were then obtained via reduction treatment assisted by hydrogen spillover. The reduction treatment at 200 °C induced the formation of surface Ti3+ exclusively, whereas surface Ti3+ and VO were formed by performing the reduction at 600 °C. The Pt/TNR with a higher aspect ratio reduced at 200 °C exhibited the highest activity in photocatalytic H2 production under visible light irradiation owing to the synergistic effect of the introduction of Ti3+ defects and the spatial charge carrier separation induced by crystal facet engineering.
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Affiliation(s)
- Yukari Yamazaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
| | - Tetsuya Toyonaga
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
| | - Naoto Doshita
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
| | - Kohsuke Mori
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasutaka Kuwahara
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Suzuko Yamazaki
- Division of Natural Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi 753-8512, Japan
| | - Hiromi Yamashita
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
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10
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Balog Á, Samu GF, Pető S, Janáky C. The Mystery of Black TiO 2: Insights from Combined Surface Science and In Situ Electrochemical Methods. ACS MATERIALS AU 2021; 1:157-168. [PMID: 34841423 PMCID: PMC8609907 DOI: 10.1021/acsmaterialsau.1c00020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Indexed: 11/28/2022]
Abstract
Titanium dioxide (TiO2) is often employed as a light absorber, electron-transporting material and catalyst in different energy and environmental applications. Heat treatment in a hydrogen atmosphere generates black TiO2 (b-TiO2), allowing better absorption of visible light, which placed this material in the forefront of research. At the same time, hydrogen treatment also introduces trap states, and the question of whether these states are beneficial or harmful is rather controversial and depends strongly on the application. We employed combined surface science and in situ electrochemical methods to scrutinize the effect of these states on the photoelectrochemical (PEC), electrocatalytic (EC), and charge storage properties of b-TiO2. Lower photocurrents were recorded with the increasing number of defect sites, but the EC and charge storage properties improved. We also found that the PEC properties can be enhanced by trap state passivation through Li+ ion intercalation in a two-step process. This passivation can only be achieved by utilizing small size cations in the electrolyte (Li+) but not with bulky ones (Bu4N+). The presented insights will help to resolve some of the controversies in the literature and also provide rational trap state engineering strategies.
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Affiliation(s)
- Ádám Balog
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Gergely F Samu
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Szabolcs Pető
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
| | - Csaba Janáky
- Department of Physical Chemistry and Materials Science, Interdisciplinary Excellence Centre, University of Szeged, Aradi Square 1, Szeged H-6720, Hungary
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11
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Feng G, Hu M, Yuan S, Nan J, Zeng H. Hydrogenated Amorphous TiO 2-x and Its High Visible Light Photoactivity. NANOMATERIALS 2021; 11:nano11112801. [PMID: 34835567 PMCID: PMC8625909 DOI: 10.3390/nano11112801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/09/2021] [Accepted: 10/15/2021] [Indexed: 12/02/2022]
Abstract
Hydrogenated crystalline TiO2 with oxygen vacancy (OV) defect has been broadly investigated in recent years. Different from crystalline TiO2, hydrogenated amorphous TiO2−x for advanced photocatalytic applications is scarcely reported. In this work, we prepared hydrogenated amorphous TiO2−x (HA-TiO2−x) using a unique liquid plasma hydrogenation strategy, and demonstrated its highly visible-light photoactivity. Density functional theory combined with comprehensive analyses was to gain fundamental understanding of the correlation among the OV concentration, electronic band structure, photon capturing, reactive oxygen species (ROS) generation, and photocatalytic activity. One important finding was that the narrower the bandgap HA-TiO2−x possessed, the higher photocatalytic efficiency it exhibited. Given the narrow bandgap and extraordinary visible-light absorption, HA-TiO2−x showed excellent visible-light photodegradation in rhodamine B (98.7%), methylene blue (99.85%), and theophylline (99.87) within two hours, as well as long-term stability. The total organic carbon (TOC) removal rates of rhodamine B, methylene blue, and theophylline were measured to 55%, 61.8%, and 50.7%, respectively, which indicated that HA-TiO2−x exhibited high wastewater purification performance. This study provided a direct and effective hydrogenation method to produce reduced amorphous TiO2−x which has great potential in practical environmental remediation.
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Affiliation(s)
- Guang Feng
- Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; (G.F.); (M.H.); (S.Y.)
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Mengyun Hu
- Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; (G.F.); (M.H.); (S.Y.)
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China;
| | - Shuai Yuan
- Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; (G.F.); (M.H.); (S.Y.)
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
| | - Junyi Nan
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China;
| | - Heping Zeng
- Shanghai Key Laboratory of Modern Optical System, Engineering Research Center of Optical Instrument and System, Ministry of Education, School of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; (G.F.); (M.H.); (S.Y.)
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China;
- CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai 201800, China
- Jinan Institute of Quantum Technology, Jinan 250101, China
- Correspondence:
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12
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Yamazaki Y, Mori K, Kuwahara Y, Kobayashi H, Yamashita H. Defect Engineering of Pt/TiO 2-x Photocatalysts via Reduction Treatment Assisted by Hydrogen Spillover. ACS APPLIED MATERIALS & INTERFACES 2021; 13:48669-48678. [PMID: 34615345 DOI: 10.1021/acsami.1c13756] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Defect engineering of metal oxides is a facile and promising strategy to improve their photocatalytic activity. In the present study, Pt/TiO2-x was prepared by a reduction treatment assisted by hydrogen spillover to pure rutile, anatase, and brookite and was subsequently used for hydrogen production from an aqueous methanol solution. With increasing reduction temperature, the photocatalytic activity of the rutile Pt/TiO2-x increased substantially, whereas the activity of anatase Pt/TiO2-x decreased and that of brookite Pt/TiO2-x was independent of the treatment temperature. Electron-spin resonance analysis revealed that rutile and brookite possess similar defect sites (Ti3+ and concomitant oxygen vacancy) after the reduction at 600 °C, whereas different resonance signals were observed for anatase after the reduction at 600 °C. During the reduction process, electrons donated from spillover hydrogen migrate between the conduction band and the inherent midgap states. This research demonstrates that the depth of the inherent midgap states, depending on the crystal phases, influences the generation of defects, which play a key role in the photocatalytic performance of Pt/TiO2-x.
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Affiliation(s)
- Yukari Yamazaki
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
| | - Kohsuke Mori
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasutaka Kuwahara
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
- JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Hisayoshi Kobayashi
- Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan
| | - Hiromi Yamashita
- Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Osaka 565-0871, Japan
- Unit of Elements Strategy Initiative for Catalysts & Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
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13
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Defective Black TiO 2: Effects of Annealing Atmospheres and Urea Addition on the Properties and Photocatalytic Activities. NANOMATERIALS 2021; 11:nano11102648. [PMID: 34685089 PMCID: PMC8541354 DOI: 10.3390/nano11102648] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 11/16/2022]
Abstract
A series of black TiO2 with and without the addition of urea were successfully prepared using a simple one-step synthetic method by calcination under different atmospheres (vacuum, He, or N2). The physicochemical, optical, and light-induced charge transfer properties of the as-prepared samples were characterized by various techniques. It was found that a vacuum atmosphere was more beneficial for the formation of oxygen vacancies (OVs) than the inert gases (He and N2) and the addition of urea-inhibited OVs formation. The samples annealed in the vacuum condition exhibited better visible-light adsorption abilities, narrower bandgaps, higher photo-induced charge separation efficiency, and lower recombination rates. Hydroxyl radicals (·OH) were the dominant oxidative species in the samples annealed under a vacuum. Finally, the samples annealed under vacuum conditions displayed higher photocatalytic activity for methylene blue (MB) degradation than the samples annealed under He or N2. Based on the above, this study provides new insights into the effects of annealing atmospheres and urea addition on the properties of black TiO2.
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14
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Abstract
Pristine and modified/doped titania are still some of the most widely investigated photocatalysts due to its high activity, stability, abundance and proper redox properties to carry out various reactions. However, modifiers and/or dopants resulting in visible-light activity might be expensive or work as recombination centers under UV irradiation. It seems that defective titania, known as “self-doped” TiO2, might be the best solution since it can be obtained under mild conditions without the addition of expensive materials and methods. This review discusses various methods of defective titania preparation, characterization of defect types, their localization (surface vs. bulk) and their function, as well as proposed mechanisms of photocatalytic reactions in the presence of self-doped titania. Although many kinds of defective titania samples have already been prepared with different colors, color intensities and defect kinds (mainly Ti3+ and oxygen vacancies), it is difficult to conclude which of them are the most recommended as the preparation conditions and activity testing used by authors differ. Furthermore, activity testing under solar radiation and for dyes does not clarify the mechanism since bare titania can also be excited and sensitized, respectively, in these conditions. In many reports, authors have not considered the possible influence of some impurities originated from the synthesis method (e.g., H, Al, Zn, Cl, F) that could co-participate in the overall mechanism of photocatalytic reactions. Moreover, some reports indicate that defective titania, especially black ones, might decrease activity since the defects might work as recombination centers. Despite some unproven/unclear findings and unanswered questions, there are many well-conducted studies confirmed by both experimental and theoretical studies that defective titania might be a promising material for various photocatalytic reactions under both UV and visible-light irradiation. Based on available literature, it could be proposed that optimal defects’ concentration, the preferential role of surface defects, a higher surface-to-bulk ratio of defects in rutile than in anatase, and the beneficial impact of disordered surface are the most important aspects to be considered during the preparation of defective titania.
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15
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Andronic L, Enesca A. Black TiO 2 Synthesis by Chemical Reduction Methods for Photocatalysis Applications. Front Chem 2020; 8:565489. [PMID: 33282823 PMCID: PMC7705109 DOI: 10.3389/fchem.2020.565489] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/24/2020] [Indexed: 11/13/2022] Open
Abstract
Applications of TiO2 nanomaterials in photocatalysis, batteries, supercapacitors and solar cells, have seen widespread development in recent decades. Nowadays, black TiO2 have won attention due to enhancing the solar light absorption by the formation of oxygen vacancies and Ti3+ defects, to promote the separation of photo-generated charge carriers leading to the improvement of the photocatalytic performance in H2 production and pollutants degradation. The enhanced photocatalytic activity of black TiO2 is also due to a lattice disorder on the surface and the presence of oxygen vacancies, Ti3+ ions, Ti-OH and Ti-H groups. Enhancing the optical absorption characteristics of TiO2 and change of energy level and band-gap of materials have been successfully demonstrated to improve their photocatalytic activities, especially for black TiO2 nanoparticles, which promote visible light absorption. The current review focuses on the investigation of the chemical reduction synthetic route for black TiO2 nanomaterials, and their proposed association with green applications such as photodegradation of organic pollutants and photocatalytic water splitting. The synthesis methods of black TiO2 involves the changes from Ti4+ to Ti3+ state, into different strategies: (1) The use of highly active hydrogen species such as H2, H2/Ar or H2/N2 gases, and metal hydrides (NaBH4, CaH2), (2) the reduction by active metals such as aluminum, magnesium and zinc, and (3) organic molecules such as imidazole and ascorbic acid.
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Affiliation(s)
- Luminita Andronic
- Department of Product Design, Mechatronics and Environment, Transilvania University of Brasov, Brasov, Romania
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16
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Quesada-Cabrera R, Parkin IP. Qualitative Approaches Towards Useful Photocatalytic Materials. Front Chem 2020; 8:817. [PMID: 33024744 PMCID: PMC7516336 DOI: 10.3389/fchem.2020.00817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/04/2020] [Indexed: 11/13/2022] Open
Abstract
The long-standing crusade searching for efficient photocatalytic materials has resulted in a vast landscape of promising photocatalysts, as reflected by the number of reviews reported in the last decade. Virtually all of these reviews have focused on quantitative approaches aiming at developing an understanding of the underlying mechanisms behind photocatalytic behavior and the parameters that influence structure–function correlation. Less attention has been paid, however, to qualitative measures around the development and assessment of photocatalysts. These measures will contribute toward narrowing the range of potential photocatalytic materials for widespread applications. The current report provides a critical perspective over some of the main factors affecting the assessment of photocatalytic materials as a code of good practice. A case of study is also provided, where this qualitative analysis is applied to one of the most prolific materials of the last-decade, disorder-engineered, black titanium dioxide (TiO2).
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Affiliation(s)
- Raul Quesada-Cabrera
- Christopher-Ingold Laboratories, Materials Chemistry Center, Department of Chemistry, UCL (University College London), London, United Kingdom
| | - Ivan P Parkin
- Christopher-Ingold Laboratories, Materials Chemistry Center, Department of Chemistry, UCL (University College London), London, United Kingdom
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17
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Black titania with increased defective sites for phenol photodegradation under visible light. REACTION KINETICS MECHANISMS AND CATALYSIS 2020. [DOI: 10.1007/s11144-020-01832-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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18
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Shen M, Ding T, Luo J, Tan C, Mahmood K, Wang Z, Zhang D, Mishra R, Lew MD, Sadtler B. Competing Activation and Deactivation Mechanisms in Photodoped Bismuth Oxybromide Nanoplates Probed by Single-Molecule Fluorescence Imaging. J Phys Chem Lett 2020; 11:5219-5227. [PMID: 32516535 DOI: 10.1021/acs.jpclett.0c01237] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Oxygen vacancies in semiconductor photocatalysts play several competing roles, serving to both enhance light absorption and charge separation of photoexcited carriers as well as act as recombination centers for their deactivation. In this Letter, we show that single-molecule fluorescence imaging of a chemically activated fluorogenic probe can be used to monitor changes in the photocatalytic activity of bismuth oxybromide (BiOBr) nanoplates in situ during the light-induced formation of oxygen vacancies. We observe that the specific activities of individual nanoplates for the photocatalytic reduction of resazurin first increase and then progressively decrease under continuous laser irradiation. Ensemble structural characterization, supported by electronic-structure calculations, shows that irradiation increases the concentration of surface oxygen vacancies in the nanoplates, reduces Bi ions, and creates donor defect levels within the band gap of the semiconductor particles. These combined changes first enhance photocatalytic activity by increasing light absorption at visible wavelengths. However, high concentrations of oxygen vacancies lower the photocatalytic activity both by introducing new relaxation pathways that promote charge recombination before photoexcited electrons can be extracted and by weakening binding of resazurin to the surface of the nanoplates.
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Affiliation(s)
- Meikun Shen
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Tianben Ding
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Jiang Luo
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Che Tan
- Department of Energy, Environmental & Chemical Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Khalid Mahmood
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Zheyu Wang
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Dongyan Zhang
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Rohan Mishra
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
- Department of Mechanical Engineering & Materials Science, Washington University, St. Louis, Missouri 63130, United States
| | - Matthew D Lew
- Department of Electrical and Systems Engineering, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
| | - Bryce Sadtler
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
- Institute of Materials Science & Engineering, Washington University, St. Louis, Missouri 63130, United States
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19
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One-Step Synthesis of b-N-TiO2/C Nanocomposites with High Visible Light Photocatalytic Activity to Degrade Microcystis aeruginosa. Catalysts 2020. [DOI: 10.3390/catal10050579] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Black TiO2 with doped nitrogen and modified carbon (b-N-TiO2/C) were successfully prepared by sol-gel method in the presence of urea as a source of nitrogen and carbon. The photocatalysts were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman, electron paramagnetic resonance (EPR), and UV-vis diffuse reflectance spectra (DRS). The doped nitrogen, introduced defects, and modified carbon played a synergistic role in enhancing photocatalytic activity of b-N-TiO2/C for the degradation of chlorophyll-a in algae cells. The sample, with a proper amount of phase composition and oxygen vacancies, showed the highest efficiency to degrade chlorophyll-a, and the addition of H2O2 promoted this photocatalysis degradation. Based on the trapping experiments and electron spin resonance (ESR) signals, a photocatalytic mechanism of b-N-TiO2/C was proposed. In the photocatalytic degradation of chlorophyll-a, the major reactive species were identified as OH and O2−. This research may provide new insights into the photocatalytic inactivation of algae cells by composite photocatalysts.
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20
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Imparato C, Iervolino G, Fantauzzi M, Koral C, Macyk W, Kobielusz M, D'Errico G, Rea I, Di Girolamo R, De Stefano L, Andreone A, Vaiano V, Rossi A, Aronne A. Photocatalytic hydrogen evolution by co-catalyst-free TiO 2/C bulk heterostructures synthesized under mild conditions. RSC Adv 2020; 10:12519-12534. [PMID: 35497602 PMCID: PMC9051216 DOI: 10.1039/d0ra01322f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 03/17/2020] [Indexed: 01/01/2023] Open
Abstract
Hydrogen production by photocatalytic water splitting is one of the most promising sustainable routes to store solar energy in the form of chemical bonds. To obtain significant H2 evolution rates (HERs) a variety of defective TiO2 catalysts were synthesized by means of procedures generally requiring highly energy-consuming treatments, e.g. hydrogenation. Even if a complete understanding of the relationship between defects, electronic structure and catalytic active sites is far from being achieved, the band gap narrowing and Ti3+-self-doping have been considered essential to date. In most reports a metal co-catalyst (commonly Pt) and a sacrificial electron donor (such as methanol) are used to improve HERs. Here we report the synthesis of TiO2/C bulk heterostructures, obtained from a hybrid TiO2-based gel by simple heat treatments at 400 °C under different atmospheres. The electronic structure and properties of the grey or black gel-derived powders are deeply inspected by a combination of classical and less conventional techniques, in order to identify the origin of their photoresponsivity. The defective sites of these heterostructures, namely oxygen vacancies, graphitic carbon and unpaired electrons localized on the C matrix, result in a remarkable visible light activity in spite of the lack of band gap narrowing or Ti3+-self doping. The materials provide HER values ranging from about 0.15 to 0.40 mmol h-1 gcat -1, under both UV- and visible-light irradiation, employing glycerol as sacrificial agent and without any co-catalyst.
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Affiliation(s)
- Claudio Imparato
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II P.le V. Tecchio 80 80125 Napoli Italy
| | - Giuseppina Iervolino
- Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II 132 84084 Fisciano (Salerno) Italy
| | - Marzia Fantauzzi
- Department of Chemical and Geological Sciences, University of Cagliari S.S. 554 Bivio per Sestu 09042 Monserrato Cagliari Italy
| | - Can Koral
- Department of Physics, University of Naples Federico II, CNR-SPIN, UOS Napoli Via Cinthia 80126 Napoli Italy
| | - Wojciech Macyk
- Faculty of Chemistry, Jagiellonian University ul. Gronostajowa 2 30-387 Kraków Poland
| | - Marcin Kobielusz
- Faculty of Chemistry, Jagiellonian University ul. Gronostajowa 2 30-387 Kraków Poland
| | - Gerardino D'Errico
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 80126 Napoli Italy
| | - Ilaria Rea
- Institute for Microelectronics and Microsystems, National Research Council Via P. Castellino 111 80131 Napoli Italy
| | - Rocco Di Girolamo
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 80126 Napoli Italy
| | - Luca De Stefano
- Institute for Microelectronics and Microsystems, National Research Council Via P. Castellino 111 80131 Napoli Italy
| | - Antonello Andreone
- Department of Physics, University of Naples Federico II, CNR-SPIN, UOS Napoli Via Cinthia 80126 Napoli Italy
| | - Vincenzo Vaiano
- Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II 132 84084 Fisciano (Salerno) Italy
| | - Antonella Rossi
- Department of Chemical and Geological Sciences, University of Cagliari S.S. 554 Bivio per Sestu 09042 Monserrato Cagliari Italy
| | - Antonio Aronne
- Department of Chemical, Materials and Production Engineering, University of Naples Federico II P.le V. Tecchio 80 80125 Napoli Italy
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21
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Liquid-Plasma Hydrogenated Synthesis of Gray Titania with Engineered Surface Defects and Superior Photocatalytic Activity. NANOMATERIALS 2020; 10:nano10020342. [PMID: 32079275 PMCID: PMC7075135 DOI: 10.3390/nano10020342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/10/2020] [Accepted: 02/13/2020] [Indexed: 01/04/2023]
Abstract
Defect engineering in photocatalysts recently exhibits promising performances in solar-energy-driven reactions. However, defect engineering techniques developed so far rely on complicated synthesis processes and harsh experimental conditions, which seriously hinder its practical applications. In this work, we demonstrated a facile mass-production approach to synthesize gray titania with engineered surface defects. This technique just requires a simple liquid-plasma treatment under low temperature and atmospheric pressure. The in situ generation of hydrogen atoms caused by liquid plasma is responsible for hydrogenation of TiO2. Electron paramagnetic resonance (EPR) measurements confirm the existence of surface oxygen vacancies and Ti3+ species in gray TiO2−x. Both kinds of defects concentrations are well controllable and increase with the output plasma power. UV–Vis diffused reflectance spectra show that the bandgap of gray TiO2−x is 2.9 eV. Due to its extended visible-light absorption and engineered surface defects, gray TiO2−x exhibits superior visible-light photoactivity. Rhodamine B was used to evaluate the visible-light photodegradation performance, which shows that the removal rate constant of gray TiO2−x reaches 0.126 min−1 and is 6.5 times of P25 TiO2. The surface defects produced by liquid-plasma hydrogenation are proved stable in air and water and could be a candidate hydrogenation strategy for other photocatalysts.
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22
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Eid K, A. Soliman K, Abdulmalik D, Mitoraj D, Sleim MH, Liedke MO, El-Sayed HA, AlJaber AS, Y. Al-Qaradawi I, Mendoza Reyes O, Abdullah AM. Tailored fabrication of iridium nanoparticle-sensitized titanium oxynitride nanotubes for solar-driven water splitting: experimental insights on the photocatalytic–activity–defects relationship. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02366f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Uniform and vertically aligned nanotube arrays of titanium oxynitride functionalized with iridium nanoparticles (Ir/TiON-NTs) were fabricated for the solar driven-water splitting.
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Affiliation(s)
- Kamel Eid
- Center for Advanced Materials
- Qatar University
- Doha
- Qatar
| | - Khaled A. Soliman
- Physical Chemistry Department
- National Research Centre
- Cairo 12441
- Egypt
| | - Dana Abdulmalik
- Department of Mathematics
- Statistics and Physics
- College of Arts and Sciences
- Qatar University
- Doha 2713
| | | | | | - Maciej O. Liedke
- Institute of Radiation Physics
- Helmholtz-Zentrum Dresden-Rossendorf
- 01328 Dresden
- Germany
| | - Hany A. El-Sayed
- Department of Chemistry
- Technische Universität München
- Lichtenbergstrasse 4
- Garching
- Germany
| | - Amina S. AlJaber
- Department of Chemistry and Earth Sciences
- College of Arts and Sciences
- Qatar University
- Doha 2713
- Qatar
| | - Ilham Y. Al-Qaradawi
- Department of Mathematics
- Statistics and Physics
- College of Arts and Sciences
- Qatar University
- Doha 2713
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23
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Bansal J, Swami SK, Singh A, Sarao T, Dutta V, Hafiz AK, Sharma SN. Apparatus-dependent sol-gel synthesis of TiO2 nanoparticles for dye-sensitized solar cells. J DISPER SCI TECHNOL 2019. [DOI: 10.1080/01932691.2019.1699427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Jyoti Bansal
- CSIR-National Physical Laboratory, New Delhi, India
- Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia, New Delhi, India
| | | | | | - Tarnija Sarao
- Department of Physics, Amity University, Noida, Uttar Pradesh, India
| | - Viresh Dutta
- Photovoltaic Lab, Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi, India
| | - A. K. Hafiz
- Centre for Nanoscience and Nanotechnology, Jamia Millia Islamia, New Delhi, India
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24
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25
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Baktash E, Capitolis J, Tinat L, Larquet C, Chan Chang THC, Gallet JJ, Bournel F, Sanchez C, Carenco S, Portehault D. Different Reactivity of Rutile and Anatase TiO 2 Nanoparticles: Synthesis and Surface States of Nanoparticles of Mixed-Valence Magnéli Oxides. Chemistry 2019; 25:11114-11120. [PMID: 31157934 DOI: 10.1002/chem.201901592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/30/2019] [Indexed: 11/09/2022]
Abstract
Magnéli phases Tin O2n-1 (3<n≤10) are mixed Ti4+ /Ti3+ oxides with high electrical conductivity. When used for water remediation or electrochemical energy storage and conversion, they are nanostructured and exposed to various environments. Therefore, understanding their surface reactivity is of prime importance. Such studies have been hindered by carbon contamination from syntheses. Herein, this synthetic and characterization challenge is addressed through a new approach to 50 nm carbon-free Ti4 O7 and Ti6 O11 nanoparticles. It takes advantage of the different reactivities of rutile and anatase TiO2 nanoparticles towards H2 , to use the former as precursor of Tin O2n-1 and the latter as a diluting agent. This approach is combined with silica templating to restrain particle growth. The surface reactivity of the Magnéli nanoparticles under different atmospheres was then evaluated quantitatively by synchrotron-radiation-based X-ray photoelectron spectroscopy, which revealed oxidized surfaces with lower conductivity than the core. This finding sheds a new light on the charge transfer occurring in these materials.
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Affiliation(s)
- Elham Baktash
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Jérôme Capitolis
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Lionel Tinat
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Clément Larquet
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Tsou Hsi Camille Chan Chang
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Jean-Jacques Gallet
- Laboratoire de Chimie Physique, Matière et Rayonnement (LPCMR), Sorbonne Université, CNRS, 4 Place Jussieu, Paris, 75005, France.,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif sur Yvette Cedex, France
| | - Fabrice Bournel
- Laboratoire de Chimie Physique, Matière et Rayonnement (LPCMR), Sorbonne Université, CNRS, 4 Place Jussieu, Paris, 75005, France.,Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192, Gif sur Yvette Cedex, France
| | - Clément Sanchez
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - Sophie Carenco
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
| | - David Portehault
- Laboratoire de Chimie de la Matière Condensée de Paris (CMCP), Sorbonne Université, CNRS, Collège de France, 4 place Jussieu, Paris, 75005, France
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26
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Guo Y, Chen S, Yu Y, Tian H, Zhao Y, Ren JC, Huang C, Bian H, Huang M, An L, Li Y, Zhang R. Hydrogen-Location-Sensitive Modulation of the Redox Reactivity for Oxygen-Deficient TiO 2. J Am Chem Soc 2019; 141:8407-8411. [PMID: 31083914 DOI: 10.1021/jacs.9b01836] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogenated black TiO2 is receiving ever-increasing attention, primarily due to its ability to capture low-energy photons in the solar spectrum and its highly efficient redox reactivity for solar-driven water splitting. However, in-depth physical insight into the redox reactivity is still missing. In this work, we conducted a density functional theory study with Hubbard U correction (DFT+U) based on the model obtained from spectroscopic and aberration-corrected scanning transmission electron microscopy (AC-STEM) characterizations to reveal the synergy among H heteroatoms located at different surface sites where the six-coordinated Ti (Ti6C) atom is converted from an inert trapping site to a site for the interchange of photoexcited electrons. This in-depth understanding may be applicable to the rational design of highly efficient solar-light-harvesting catalysts.
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Affiliation(s)
- Yao Guo
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China.,Shenzhen Research Institute , City University of Hong Kong , Shenzhen , P. R. China
| | - Shunwei Chen
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Yaoguang Yu
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Haoran Tian
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Yanling Zhao
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China.,Shenzhen Research Institute , City University of Hong Kong , Shenzhen , P. R. China
| | - Ji-Chang Ren
- Nano and Heterogeneous Materials Center, School of Materials Science and Engineering , Nanjing University of Science and Technology , Nanjing , Jiangsu , P. R. China
| | - Chao Huang
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Haidong Bian
- Department of Materials Science and Engineering , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Miaoyan Huang
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Liang An
- Department of Mechanical Engineering , The Hong Kong Polytechnic University , Hong Kong SAR , P. R. China
| | - Yangyang Li
- Department of Materials Science and Engineering , City University of Hong Kong , Hong Kong SAR , P. R. China
| | - Ruiqin Zhang
- Department of Physics , City University of Hong Kong , Hong Kong SAR , P. R. China.,Beijing Computational Science Research Center , Beijing 100875 , P. R. China
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Lin J, Liu Y, Liu Y, Huang C, Liu W, Mi X, Fan D, Fan F, Lu H, Chen X. SnS 2 Nanosheets/H-TiO 2 Nanotube Arrays as a Type II Heterojunctioned Photoanode for Photoelectrochemical Water Splitting. CHEMSUSCHEM 2019; 12:961-967. [PMID: 30716210 DOI: 10.1002/cssc.201802691] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/23/2018] [Indexed: 06/09/2023]
Abstract
Improving the separation efficiency of photogenerated electron-hole pairs and the conductivity of electrons to photoanode substrates are critical to achieve high-performance photoelectrochemical (PEC) water splitting. Here, a SnS2 /H-TiO2 /Ti heterojunction photoanode was fabricated with SnS2 nanosheets vertically grown on hydrogen-treated TiO2 (H-TiO2 ) nanotube arrays on a Ti substrate. It showed a significantly enhanced photocurrent of 4.0 mA cm-2 at 1.4 V (vs. reversible hydrogen electrode) under AM 1.5 G illumination, 70 times higher than that of SnS2 /TiO2 /Ti. Kelvin probe force microscopy measurements indicated that photogenerated electrons could be easily transported through the SnS2 /H-TiO2 interface but not through the SnS2 /TiO2 interface. Through hydrogen treatment, defects were created in H-TiO2 nanotubes to convert type I junctions to type II with SnS2 nanosheets. As a result, a high efficiency of electron-hole separation at the SnS2 /H-TiO2 interface and a high electron conductivity in H-TiO2 nanotubes were achieved and improved PEC performance. These findings show an effective route towards high-performance photoelectrodes for water splitting.
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Affiliation(s)
- Jianfei Lin
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
| | - Yong Liu
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P.R. China
| | - Yongping Liu
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri, 64110, USA
| | - Chen Huang
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
| | - Wenhui Liu
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
| | - Xihong Mi
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
| | - Dayong Fan
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
| | - Fengtao Fan
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, P.R. China
| | - Huidan Lu
- Guangxi Key Laboratory of Electrochemical and Magneto-chemical, Functional Materials, College of Chemistry and Bioengineering, Guilin University of Technology, Guilin, 541004, P.R. China
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri, 64110, USA
| | - Xiaobo Chen
- Department of Chemistry, University of Missouri-Kansas City, Kansas City, Missouri, 64110, USA
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Naldoni A, Altomare M, Zoppellaro G, Liu N, Kment Š, Zbořil R, Schmuki P. Photocatalysis with Reduced TiO 2: From Black TiO 2 to Cocatalyst-Free Hydrogen Production. ACS Catal 2019; 9:345-364. [PMID: 30701123 PMCID: PMC6344061 DOI: 10.1021/acscatal.8b04068] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/26/2018] [Indexed: 12/22/2022]
Abstract
Black TiO2 nanomaterials have recently emerged as promising candidates for solar-driven photocatalytic hydrogen production. Despite the great efforts to synthesize highly reduced TiO2, it is apparent that intermediate degree of reduction (namely, gray titania) brings about the formation of peculiar defective catalytic sites enabling cocatalyst-free hydrogen generation. A precise understanding of the structural and electronic nature of these catalytically active sites is still elusive, as well as the fundamental structure-activity relationships that govern formation of crystal defects, increased light absorption, charge separation, and photocatalytic activity. In this Review, we discuss the basic concepts that underlie an effective design of reduced TiO2 photocatalysts for hydrogen production such as (i) defects formation in reduced TiO2, (ii) analysis of structure deformation and presence of unpaired electrons through electron paramagnetic resonance spectroscopy, (iii) insights from surface science on electronic singularities due to defects, and (iv) the key differences between black and gray titania, that is, photocatalysts that require Pt-modification and cocatalyst-free photocatalytic hydrogen generation. Finally, future directions to improve the performance of reduced TiO2 photocatalysts are outlined.
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Affiliation(s)
- Alberto Naldoni
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Marco Altomare
- Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany
| | - Giorgio Zoppellaro
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Ning Liu
- Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany
| | - Štěpán Kment
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Radek Zbořil
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
| | - Patrik Schmuki
- Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc, Czech Republic
- Department of Materials Science and Engineering, University of Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany
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Tian M, Dyck O, Ge J, Duscher G. Measuring the areal density of nanomaterials by electron energy-loss spectroscopy. Ultramicroscopy 2018; 196:154-160. [PMID: 30391804 DOI: 10.1016/j.ultramic.2018.10.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 10/14/2018] [Accepted: 10/25/2018] [Indexed: 11/17/2022]
Abstract
Thickness measurements of nanomaterials are usually performed using transmission electron microscopy (TEM) techniques such as convergent beam electron diffraction (CBED) patterns analysis and the log-ratio method based on electron energy-loss spectroscopy (EELS) spectrum. However, it is challenging to obtain both the thickness and elemental information, especially in non-crystalline materials or for very thin samples. In this work, we establish a series of procedures to calculate the areal density of the material by directly measuring the inelastic scattering probability in a thin sample. Core-loss EELS are fit with a quantitative model to extract atomic areal density. Knowledge of one of the parameters (volume density or sample thickness) allows a measurement of the other. The absolute error between the known thicknesses and those measured was less than 4% using two-dimensional materials with a well-defined thickness as test samples, which is much better than the log-ratio method for very thin samples. One promising advantage of this method is the thickness/areal density determination in mixed phase/element systems. We use Ag-Co bimetallic triangles and black rutile as examples to calculate the thickness map in mixture systems in different cases. We also demonstrate this technique can be applied to measure the argon gas density in spherical cavities. This allows a temperature vs pressure curve to be obtained and illustrates the unique capability of this technique.
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Affiliation(s)
- Mengkun Tian
- Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37909, USA.
| | - Ondrej Dyck
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Jingxuan Ge
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Gerd Duscher
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA; Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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30
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Asok A, Deshlahra P, Ramachandran AM, Kulkarni AR. Multifunctional Photostable Nanocomplex of ZnO Quantum Dots and Avobenzone via the Promotion of Enolate Tautomer. GLOBAL CHALLENGES (HOBOKEN, NJ) 2018; 2:1800025. [PMID: 31565311 PMCID: PMC6607145 DOI: 10.1002/gch2.201800025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 05/29/2018] [Indexed: 06/10/2023]
Abstract
Ideal multifunctional ultraviolet radiation (UVR) absorbents with excellent photostability, high molar absorptivity, broadband UVR screening, and desired skin sensorial properties remain a significant challenge for the sunscreen industry. The potential of the nanocomplex (NCx) formed by microwave synthesis of ZnO quantum dots (QDs) in the presence of Avobenzone (Av) for achieving these goals is reported. The NCx exhibits unique synergy between ZnO QD and Av components, which enhances the photostability and molar absorptivity, extends UVA filtering range, and provides a visible emission that matches the typical human in vivo skin emission color. Density functional theory (DFT) and time-dependent DFT calculations of ZnO-Av hybrid structures and comparison of their spectroscopic features with experiments suggest that ZnO QDs catalyze the formation of highly photostable surface enolate species via aldol condensation reaction. The combination of experiments and computations used in this study can advance the science and technology of photoprotection.
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Affiliation(s)
- Adersh Asok
- Materials Science and Technology DivisionNational Institute for Interdisciplinary Science and TechnologyCouncil of Scientific and Industrial ResearchThiruvananthapuram695019India
| | - Prashant Deshlahra
- Department of Chemical and Biological EngineeringTufts University4 Colby St.MedfordMA02155USA
| | - Animesh M. Ramachandran
- Materials Science and Technology DivisionNational Institute for Interdisciplinary Science and TechnologyCouncil of Scientific and Industrial ResearchThiruvananthapuram695019India
| | - Ajit R. Kulkarni
- Department of Metallurgical Engineering and Materials ScienceIndian Institute of Technology BombayMumbai400076India
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Cho Y, Kim S, Park B, Lee CL, Kim JK, Lee KS, Choi IY, Kim JK, Zhang K, Oh SH, Park JH. Multiple Heterojunction in Single Titanium Dioxide Nanoparticles for Novel Metal-Free Photocatalysis. NANO LETTERS 2018; 18:4257-4262. [PMID: 29902008 DOI: 10.1021/acs.nanolett.8b01245] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Despite a longstanding controversy surrounding TiO2 materials, TiO2 polymorphs with heterojunctions composed of anatase and rutile outperform individual polymorphs because of the type-II energetic band alignment at the heterojunction interface. Improvement in photocatalysis has also been achieved via black TiO2 with a thin disorder layer surrounding ordered TiO2. However, localization of this disorder layer in a conventional single TiO2 nanoparticle with the heterojunction composed of anatase and rutile has remained a big challenge. Here, we report the selective positioning of a disorder layer of controlled thicknesses between the anatase and rutile phases by a conceptually different synthetic route to access highly efficient novel metal-free photocatalysis for H2 production. The presence of a localized disorder layer within a single TiO2 nanoparticle was confirmed for the first time by high-resolution transmission electron microscopy with electron energy-loss spectroscopy and inline electron holography. Multiple heterojunctions in single TiO2 nanoparticles composed of crystalline anatase/disordered rutile/ordered rutile layers give the nanoparticles superior electron/hole separation efficiency and novel metal-free surface reactivity, which concomitantly yields an H2 production rate that is ∼11-times higher than that of Pt-decorated conventional anatase and rutile single heterojunction TiO2 systems.
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Affiliation(s)
- Yoonjun Cho
- Department of Chemical and Biomolecular Engineering , Yonsei University , 50 Yonsei-ro, Seodaemun-gu , Seoul 120-749 , Republic of Korea
| | - Sungsoon Kim
- Department of Chemical and Biomolecular Engineering , Yonsei University , 50 Yonsei-ro, Seodaemun-gu , Seoul 120-749 , Republic of Korea
| | - Bumsu Park
- Department of Materials Science and Engineering , Pohang University of Science and Technology , Pohang 790-784 , Republic of Korea
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
- Department of Physics, Center for Nanotubes and Nanostructured Composites (CNNC) , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Chang-Lyoul Lee
- Advanced Photonics Research Institute (APRI) , Gwangju Institute of Science and Technology (GIST) , Gwangju 500-712 , Republic of Korea
| | - Jung Kyu Kim
- School of Chemical Engineering , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Kug-Seung Lee
- Beamline Division , Pohang Accelerator Laboratory , Pohang 790-834 , Republic of Korea
| | - Il Yong Choi
- Department of Materials Science and Engineering , Pohang University of Science and Technology , Pohang 790-784 , Republic of Korea
| | - Jong Kyu Kim
- Department of Materials Science and Engineering , Pohang University of Science and Technology , Pohang 790-784 , Republic of Korea
| | - Kan Zhang
- Department of Chemical and Biomolecular Engineering , Yonsei University , 50 Yonsei-ro, Seodaemun-gu , Seoul 120-749 , Republic of Korea
- College of Materials Science and Engineering , Nanjing University of Science and Technology , Nanjing 210094 , People's Republic of China
| | - Sang Ho Oh
- Department of Energy Science , Sungkyunkwan University , Suwon 16419 , Republic of Korea
| | - Jong Hyeok Park
- Department of Chemical and Biomolecular Engineering , Yonsei University , 50 Yonsei-ro, Seodaemun-gu , Seoul 120-749 , Republic of Korea
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33
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Du K, Liu G, Chen X, Wang K. Fast charge separation and photocurrent enhancement on black TiO2 nanotubes co-sensitized with Au nanoparticles and PbS quantum dots. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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34
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Change of band-gap position of MTiO2 particle doped with 3d-transition metal and control of product selectivity on carbon dioxide photoreduction. KOREAN J CHEM ENG 2018. [DOI: 10.1007/s11814-017-0286-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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35
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Vequizo JJM, Kamimura S, Ohno T, Yamakata A. Oxygen induced enhancement of NIR emission in brookite TiO 2 powders: comparison with rutile and anatase TiO 2 powders. Phys Chem Chem Phys 2018; 20:3241-3248. [PMID: 29105714 DOI: 10.1039/c7cp06975h] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Brookite TiO2 attracts considerable attention in photocatalysis owing to its superior performance in several photocatalytic reactions. In this work, we investigated the behavior of charge carriers in brookite, rutile, and anatase TiO2 by using photoluminescence (PL) and transient absorption (TA) spectroscopies. PL measurements revealed that brookite TiO2 exhibits a visible and a NIR emission at ∼520 nm and ∼860 nm, respectively. Addition of methanol vapor quenched both the visible and NIR emissions by the hole-consuming reaction of methanol. However, exposure to O2 shows curious behaviors: the visible emission was quenched but the NIR emission was enhanced. These results can be accounted for by the enhancement of upward band bending resulting in the effective separation of electrons and holes into the bulk and the surface, respectively. Furthermore, the shallowly trapped electrons, which are responsible for visible PL, are consumed by O2; hence, the visible emission is quenched. However, in the case of NIR emission, the deeply trapped electrons are responsible and they are mainly located at the surface defects. The O2 adsorption promotes the hole accumulation at the surface and then assists the recombination of these deeply trapped electrons, resulting in the enhancement of the NIR emission. We also found that the lifetime of NIR emission (τ1 = 43 ± 0 ns and τ2 = 589 ± 1 ns) was much longer than that of visible emission (τ1 = 15 ± 0 ns and τ2 = 23 ± 0 ns), since the mobility of these deeply trapped electrons to encounter with holes is lower than that of the shallowly trapped electrons. However, even for this slow NIR emission, the actual lifetime of the deeply trapped electrons estimated by TA (1.5 ± 0.0 μs and 17 ± 0 μs) was one or two orders of magnitude longer, confirming that non-radiative recombination is dominant and it is much slower than radiative recombination: TAS and PL provide detailed information on the radiative and non-radiative recombination processes. The PL of anatase and rutile TiO2 powders was also measured and the difference from brookite TiO2 was discussed.
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Affiliation(s)
- Junie Jhon M Vequizo
- Graduate School of Engineering, Toyota Technological Institute, 2-12-1 Hisakata, Tempaku, Nagoya 468-8511, Japan.
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36
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Biswas A, Chakraborty A, Jana NR. Nitrogen and Fluorine Codoped, Colloidal TiO 2 Nanoparticle: Tunable Doping, Large Red-Shifted Band Edge, Visible Light Induced Photocatalysis, and Cell Death. ACS APPLIED MATERIALS & INTERFACES 2018; 10:1976-1986. [PMID: 29257666 DOI: 10.1021/acsami.7b14025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Visible light photocatalysis by TiO2 requires efficient doping of other elements with red-shifted band edge to the visible region. However, preparation of such TiO2 with tunable doping is challenging. Here we report a method of making nitrogen (N) and fluorine (F) codoped TiO2 nanoparticle with tunable doping between 1 and 7 at. %. The preparation of N, F codoped TiO2 nanoparticle involves reaction of colloidal TiO2 nanorods with an ammonium fluoride-urea mixture at 300 °C, and the extent of N/F doping is tuned by varying the amount of ammonium fluoride-urea and the reaction time. Resultant colloidal N, F codoped TiO2 nanoparticles show doping dependent shifting of the band edge from the UV to near-IR region, visible light induced generation of reactive oxygen species (ROS), and visible light photodegradation of bisphenol A. A colloidal form of doped TiO2 nanoparticle offers labeling of cells, visible light induced ROS generation inside a cell, and successive cell death. This work shows the potential advantage of anisotropic nanoparticle precursor for tunable doping and colloidal form of N, F codoped TiO2 nanoparticle as a visible light photocatalyst.
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Affiliation(s)
- Aritra Biswas
- Centre for Advanced Materials, Indian Association for the Cultivation of Science , Kolkata 700032, India
| | - Atanu Chakraborty
- Centre for Advanced Materials, Indian Association for the Cultivation of Science , Kolkata 700032, India
| | - Nikhil R Jana
- Centre for Advanced Materials, Indian Association for the Cultivation of Science , Kolkata 700032, India
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37
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Hou L, Guan Z, Zhang M, He C, Li Q, Yang J. Adjusting the ratio of bulk single-electron-trapped oxygen vacancies/surface oxygen vacancies in TiO2 for efficient photocatalytic hydrogen evolution. Catal Sci Technol 2018. [DOI: 10.1039/c8cy00644j] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Co-existence of bulk single-electron-trapped and surface oxygen vacancies favor the improvement of photocatalytic hydrogen evolution.
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Affiliation(s)
- Lili Hou
- National & Local Joint Engineering Research Centre for Applied Technology of Hybrid Nanomaterials
- Collaborative Innovation Centre of Nano Functional Materials and Applications of Henan Province
- Henan University
- Kaifeng
- China
| | - Zhongjie Guan
- National & Local Joint Engineering Research Centre for Applied Technology of Hybrid Nanomaterials
- Collaborative Innovation Centre of Nano Functional Materials and Applications of Henan Province
- Henan University
- Kaifeng
- China
| | - Min Zhang
- National & Local Joint Engineering Research Centre for Applied Technology of Hybrid Nanomaterials
- Collaborative Innovation Centre of Nano Functional Materials and Applications of Henan Province
- Henan University
- Kaifeng
- China
| | - Chunqing He
- Key Laboratory of Nuclear Solid State Physics Hubei Province
- School of Physics and Technology
- Wuhan University
- Wuhan
- China
| | - Qiuye Li
- National & Local Joint Engineering Research Centre for Applied Technology of Hybrid Nanomaterials
- Collaborative Innovation Centre of Nano Functional Materials and Applications of Henan Province
- Henan University
- Kaifeng
- China
| | - Jianjun Yang
- National & Local Joint Engineering Research Centre for Applied Technology of Hybrid Nanomaterials
- Collaborative Innovation Centre of Nano Functional Materials and Applications of Henan Province
- Henan University
- Kaifeng
- China
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38
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Zhou X, Liu N, Schmuki P. Photocatalysis with TiO2 Nanotubes: “Colorful” Reactivity and Designing Site-Specific Photocatalytic Centers into TiO2 Nanotubes. ACS Catal 2017. [DOI: 10.1021/acscatal.6b03709] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xuemei Zhou
- Department
of Materials Science WW4, LKO, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen, Germany
| | - Ning Liu
- Department
of Materials Science WW4, LKO, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen, Germany
| | - Patrik Schmuki
- Department
of Materials Science WW4, LKO, University of Erlangen-Nuremberg, Martensstrasse 7, 91058 Erlangen, Germany
- Department
of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21569, Saudi Arabia
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