1
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Hyun Kim Y, Gyeong Bae Y, Yong Sohn W. Uncovering Energetic Positions of Surface Trap States in α-Fe 2O 3 Treated with Cobalt Phosphate (Co-Pi) Using Charge Carrier-Selective Heterodyne Transient Grating Technique. Chemphyschem 2024; 25:e202300894. [PMID: 38369879 DOI: 10.1002/cphc.202300894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 02/17/2024] [Accepted: 02/18/2024] [Indexed: 02/20/2024]
Abstract
Near-field heterodyne transient grating (NF-HD-TG) responses of hematite (α-Fe2O3) treated with cobalt phosphate (Co-Pi) were measured with the burn lasers inducing the depletion of the response by the removal of the trapped charge carriers in the target state, which is called charge carrier-selective heterodyne transient grating (CS-HD-TG) spectroscopic technique. We found that two distinct trap states co-existed in Co-Pi loaded on the surface of α-Fe2O3. One of them named r-SS2, of which potential was similar to that of r-SS1 in the surface of α-Fe2O3, acted as a recombination centre but could increase the lifetime of the trapped holes by the charge separation. We also revealed that the energetic position of the other (i-SS2), which has been regarded as the intermediate state for oxygen evolution reaction with low overpotential, was higher than that of i-SS1 in α-Fe2O3 but lower than those of r-SS1 and r-SS2.
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Affiliation(s)
- Young Hyun Kim
- Department of Chemistry, Chungbuk National University, Chungdae-ro 1, Cheongju, Chungbuk 28644, Korea
| | - Yu Gyeong Bae
- Department of Chemistry, Chungbuk National University, Chungdae-ro 1, Cheongju, Chungbuk 28644, Korea
| | - Woon Yong Sohn
- Department of Chemistry, Chungbuk National University, Chungdae-ro 1, Cheongju, Chungbuk 28644, Korea
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2
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Adamowicz W, Yaemsunthorn K, Kobielusz M, Macyk W. Photocatalytic Transformation of Organics to Valuable Chemicals - Quo Vadis? Chempluschem 2024:e202400171. [PMID: 38679579 DOI: 10.1002/cplu.202400171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Recent development in photocatalysis is increasingly focused on transforming organic compounds toward producing fine chemicals. Simple, non-selective oxidation reactions (degradation of pollutants) and very demanding solar-to-chemical energy conversion processes (production of solar fuels) face severe economic limitations influenced by still low efficiency and insufficient stability of the systems. Synthesis of fine chemicals, including reductive and oxidative selective transformations, as well as C-C and C-N coupling reactions, can utilise the power of photocatalysis. Herein, we present the recent progress in photocatalytic systems designed to synthesise fine chemicals. In particular, we discuss the factors influencing the efficiency and selectivity of the organic transformations, dividing them into intrinsic (related to individual properties of photocatalysts) and extrinsic (originating from the reaction environment). A rational design of the photocatalytic systems, based on a deep understanding of these factors, opens new perspectives for applied photocatalysis.
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Affiliation(s)
- Wiktoria Adamowicz
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Kraków, Poland
- Doctoral School of Exact and Natural Sciences, Jagiellonian University, ul. Łojasiewicza 11, 30-348, Kraków, Poland
| | - Kasidid Yaemsunthorn
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Kraków, Poland
- Faculty of Chemical Engineering and Technology, Cracow University of Technology, Warszawska 24, 31-155, Kraków, Poland
| | - Marcin Kobielusz
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Kraków, Poland
| | - Wojciech Macyk
- Faculty of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387, Kraków, Poland
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3
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Machreki M, Chouki T, Tyuliev G, Žigon D, Ohtani B, Loukanov A, Stefanov P, Emin S. Defective TiO 2 Nanotube Arrays for Efficient Photoelectrochemical Degradation of Organic Pollutants. ACS OMEGA 2023; 8:21605-21617. [PMID: 37360499 PMCID: PMC10286085 DOI: 10.1021/acsomega.3c00820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/24/2023] [Indexed: 06/28/2023]
Abstract
Oxygen vacancies (OVs) are one of the most critical factors that enhance the electrical and catalytic characteristics of metal oxide-based photoelectrodes. In this work, a simple procedure was applied to prepare reduced TiO2 nanotube arrays (NTAs) (TiO2-x) via a one-step reduction method using NaBH4. A series of characterization techniques were used to study the structural, optical, and electronic properties of TiO2-x NTAs. X-ray photoelectron spectroscopy confirmed the presence of defects in TiO2-x NTAs. Photoacoustic measurements were used to estimate the electron-trap density in the NTAs. Photoelectrochemical studies show that the photocurrent density of TiO2-x NTAs was nearly 3 times higher than that of pristine TiO2. It was found that increasing OVs in TiO2 affects the surface recombination centers, enhances electrical conductivity, and improves charge transport. For the first time, a TiO2-x photoanode was used in the photoelectrochemical (PEC) degradation of a textile dye (basic blue 41, B41) and ibuprofen (IBF) pharmaceutical using in situ generated reactive chlorine species (RCS). Liquid chromatography coupled with mass spectrometry was used to study the mechanisms for the degradation of B41 and IBF. Phytotoxicity tests of B41 and IBF solutions were performed using Lepidium sativum L. to evaluate the potential acute toxicity before and after the PEC treatment. The present work provides efficient PEC degradation of the B41 dye and IBF in the presence of RCS without generating harmful products.
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Affiliation(s)
- Manel Machreki
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Takwa Chouki
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
| | - Georgi Tyuliev
- Institute
of Catalysis, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Bldg. 11, Sofia 1113, Bulgaria
| | - Dušan Žigon
- Institute
“Jožef Stefan”, Jamova 39, 1000 Ljubljana, Slovenia
| | - Bunsho Ohtani
- Catalysis
Research Center, Hokkaido University, N21, W10, 001-0021 Sapporo, Japan
| | - Alexandre Loukanov
- Department
of Chemistry and Materials Science, National Institute of Technology, Gunma College, 580 Toriba, Maebashi 371-8530, Gunma, Japan
| | - Plamen Stefanov
- Institute
of General and Inorganic Chemistry, Bulgarian
Academy of Sciences, Sofia 1113, Bulgaria
| | - Saim Emin
- Materials
Research Laboratory, University of Nova
Gorica, Vipavska 11c, 5270 Ajdovščina, Slovenia
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Mohamed Zahidi M, Mamat MH, Subki ASRA, Abdullah MH, Hassan H, Ahmad MK, Bakar SA, Mohamed A, Ohtani B. Formation of a Nanorod-Assembled TiO 2 Actinomorphic-Flower-like Microsphere Film via Ta Doping Using a Facile Solution Immersion Method for Humidity Sensing. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:256. [PMID: 36678009 PMCID: PMC9861450 DOI: 10.3390/nano13020256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/02/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Abstract
This study fabricated tantalum (Ta)-doped titanium dioxide with a unique nanorod-assembled actinomorphic-flower-like microsphere structured film. The Ta-doped TiO2 actinomorphic-flower-like microsphere (TAFM) was fabricated via the solution immersion method in a Schott bottle with a home-made improvised clamp. The samples were characterised using FESEM, HRTEM, XRD, Raman, XPS, and Hall effect measurements for their structural and electrical properties. Compared to the undoped sample, the rutile-phased TAFM sample had finer nanorods with an average 42 nm diameter assembled to form microsphere-like structures. It also had higher oxygen vacancy sites, electron concentration, and mobility. In addition, a reversed double-beam photoacoustic spectroscopy measurement was performed for TAFM, revealing that the sample had a high electron trap density of up to 2.5 μmolg-1. The TAFM showed promising results when employed as the resistive-type sensing film for a humidity sensor, with the highest sensor response of 53,909% obtained at 3 at.% Ta doping. Adding rGO to 3 at.% TAFM further improved the sensor response to 232,152%.
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Affiliation(s)
- Musa Mohamed Zahidi
- NANO-ElecTronic Centre (NET), School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
- Centre for Electrical Engineering Studies, Universiti Teknologi MARA Cawangan Pulau Pinang, Permatang Pauh 13500, Pulau Pinang, Malaysia
| | - Mohamad Hafiz Mamat
- NANO-ElecTronic Centre (NET), School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
| | - A Shamsul Rahimi A Subki
- NANO-ElecTronic Centre (NET), School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
- Faculty of Electrical and Electronic Engineering Technology, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal 76100, Melaka, Malaysia
| | - Mohd Hanapiah Abdullah
- NANO-ElecTronic Centre (NET), School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
- Centre for Electrical Engineering Studies, Universiti Teknologi MARA Cawangan Pulau Pinang, Permatang Pauh 13500, Pulau Pinang, Malaysia
| | - Hamizura Hassan
- Centre for Chemical Engineering Studies, Universiti Teknologi MARA Cawangan Pulau Pinang, Permatang Pauh 13500, Pulau Pinang, Malaysia
| | - Mohd Khairul Ahmad
- Microelectronic and Nanotechnology—Shamsuddin Research Centre, Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, Batu Pahat 86400, Johor, Malaysia
| | - Suriani Abu Bakar
- Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim 35900, Perak, Malaysia
| | - Azmi Mohamed
- Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim 35900, Perak, Malaysia
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
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5
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Uesugi Y, Nagakawa H, Nagata M. Highly Efficient Photocatalytic Degradation of Hydrogen Sulfide in the Gas Phase Using Anatase/TiO 2(B) Nanotubes. ACS OMEGA 2022; 7:11946-11955. [PMID: 35449917 PMCID: PMC9016837 DOI: 10.1021/acsomega.1c07294] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 03/22/2022] [Indexed: 06/14/2023]
Abstract
Hydrogen sulfide (H2S) is a highly toxic and corrosive gas that causes a foul odor even at very low concentrations [several parts per billion (ppb)]. However, industrially discharged H2S has a concentration range of several tens of ppb to several parts per million (ppm), which conventional methods are unable to process. Therefore, advanced and sustainable methods for treating very low concentrations of H2S are urgently needed. TiO2-based photocatalysts are eco-friendly and have the ability to treat environmental pollutants, such as low-concentration gases, using light energy. However, there are no reports on H2S decomposition or oxidation at concentrations below several ppb. Therefore, in this study, we employed anatase/TiO2(B) nanotubes, which have a high specific surface area and an efficient charge-transfer interface, to treat H2S. We successfully reduced 10 ppm of H2S to 1 ppb or less at a kinetic rate of 75 μmol h-1 g-1. The suitability of our method was further demonstrated by the generation of sulfate ions and sulfur (as detected by X-ray photoelectron spectroscopy and ion chromatography), which are industrially useful as oxidation products, whereas sulfur dioxide, a harmful substance, was not produced. This is the first study to report H2S decomposition down to the ppb level, providing meaningful solutions for malodor problems and potential health hazards associated with H2S.
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6
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Sakuna P, Ketwong P, Ohtani B, Trakulmututa J, Kobkeatthawin T, Luengnaruemitchai A, Smith SM. The Influence of Metal-Doped Graphitic Carbon Nitride on Photocatalytic Conversion of Acetic Acid to Carbon Dioxide. Front Chem 2022; 10:825786. [PMID: 35402383 PMCID: PMC8983859 DOI: 10.3389/fchem.2022.825786] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Metal-doped graphitic carbon nitride (MCN) materials have shown great promise as effective photocatalysts for the conversion of acetic acid to carbon dioxide under UV–visible irradiation and are superior to pristine carbon nitride (g-C3N4, CN). In this study, the effects of metal dopants on the physicochemical properties of metal-doped CN samples (Fe-, Cu-, Zn-, FeCu-, FeZn-, and CuZn-doped CN) and their catalytic activity in the photooxidation of acetic acid were investigated and discussed for their correlation, especially on their surface and bulk structures. The materials in the order of highest to lowest photocatalytic activity are FeZn_CN, FeCu_CN, Fe_CN, and Cu_CN (rates of CO2 evolution higher than for CN), followed by Zn_CN, CuZn_CN, and CN (rates of CO2 evolution lower than CN). Although Fe doping resulted in the extension of the light absorption range, incorporation of metals did not significantly alter the crystalline phase, morphology, and specific surface area of the CN materials. However, the extension of light absorption into the visible region on Fe doping did not provide a suitable explanation for the increase in photocatalytic efficiency. To further understand this issue, the materials were analyzed using two complementary techniques, reversed double-beam photoacoustic spectroscopy (RDB-PAS) and electron spin resonance spectroscopy (ESR). The FeZn_CN, with the highest electron trap density between 2.95 and 3.00 eV, afforded the highest rate of CO2 evolution from acetic acid photodecomposition. All Fe-incorporated CN materials and Cu-CN reported herein can be categorized as high activity catalysts according to the rates of CO2 evolution obtained, higher than 0.15 μmol/min−1, or >1.5 times higher than that of pristine CN. Results from this research are suggestive of a correlation between the rate of CO2 evolution via photocatalytic oxidation of acetic acid with the threshold number of free unpaired electrons in CN-based materials and high electron trap density (between 2.95 and 3.00 eV).
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Affiliation(s)
- Pichnaree Sakuna
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | | | - Bunsho Ohtani
- Institute for Catalysis, Hokkaido University, Sapporo, Japan
- *Correspondence: Bunsho Ohtani, ; Siwaporn Meejoo Smith,
| | - Jirawat Trakulmututa
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | - Thawanrat Kobkeatthawin
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
| | | | - Siwaporn Meejoo Smith
- Center of Sustainable Energy and Green Materials and Department of Chemistry, Faculty of Science, Mahidol University, Nakhon Pathom, Thailand
- *Correspondence: Bunsho Ohtani, ; Siwaporn Meejoo Smith,
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7
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Ohtani B, Takashima M. Happy photocatalysts and unhappy photocatalysts: electron trap-distribution analysis for metal oxide-sample identification. Catal Sci Technol 2022. [DOI: 10.1039/d1cy01955d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An attempt to identify inorganic solids, such as metal oxides, using ERDT (energy-resolved distribution of electron traps)/CBB (conduction-band bottom) patterns, measured by reversed double-beam spectroscopy, as a “fingerprint” is introduced.
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Affiliation(s)
- Bunsho Ohtani
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
| | - Mai Takashima
- Institute for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
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8
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Sudrajat H, Hartuti S, Babel S. Mechanistic understanding of the increased photoactivity of TiO 2 nanosheets upon tantalum doping. Phys Chem Chem Phys 2021; 24:995-1006. [PMID: 34918718 DOI: 10.1039/d1cp03907e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Anatase TiO2 is doped with Ta cations through a hydrothermal route. Based on X-ray photoelectron spectroscopy and X-ray absorption near-edge structure spectroscopy, the Ta dopants exist in the 5+-oxidation state. The oxidation state is insensitive to the Ta loading amount. Extended X-ray absorption fine structure spectroscopy confirms that the local structure around Ta cations is not identical between the Ta-doped samples. The Ta-O distance monotonically increases with the Ta loading amount due to a gradually expanding lattice. The Ta-doped samples show higher activity than pristine TiO2 for photomineralizing recalcitrant organics. The enhanced photocatalytic activity is proposed to be due to an enhanced population of photoexcited electrons, as probed using light-induced IR absorption spectroscopy, and an extended electron lifetime, as probed using time-resolved microwave conductivity, which are associated with the formation of Ti3+ defect states acting as shallow electron traps. The maximum photocatalytic activity is observed for TiO2 doped with 2 mol% of Ta, which shows enhancement of mineralization efficiency (about 3 times) and enhancement of electron population (up to 20 times), as compared to those of pristine TiO2. The fundamental question of why a proper metal doping into TiO2 increases photocatalytic activity is discussed in this study.
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Affiliation(s)
- Hanggara Sudrajat
- Department of Chemical Engineering, Faculty of Engineering, Universitas Jember, Jember, Indonesia. .,Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam.,Faculty of Applied Sciences, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam
| | - Sri Hartuti
- Department of Environmental and Renewable Energy Systems, School of Engineering, Gifu University, Gifu, Japan
| | - Sandhya Babel
- School of Biochemical Engineering and Technology, Sirindhorn International Institute of Technology, Thammasat University, Pathum Thani, Thailand
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9
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Kojima R, Ohtani B, Tada H. Photocatalytic Activity of Radial Rutile Titanium(IV) Oxide Microspheres for Aerobic Oxidation of Organics. Chemphyschem 2021; 23:e202100793. [PMID: 34918451 DOI: 10.1002/cphc.202100793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/08/2021] [Indexed: 11/07/2022]
Abstract
Radial rutile TiO2 nanorod homomesocrystals (TiO2 -NR HOMCs) or the so-called "sea urchin-like TiO2 microspheres" were synthesized by using a hydrothermal method. TiO2 -NR HOMCs show photocatalytic activity for aerobic oxidative degradation of 2-naphthol under irradiation of UV- and visible light. Furthermore, extremely small iron oxide clusters were formed on the surface of TiO2 -NR HOMCs (FeOx /TiO2 -NR HOMCs) by the chemisorption-calcination technique to reduce the band gap. The FeOx -surface modification gives rise to drastic enhancement of the UV- and visible-light activity. Reversed double-beam photoacoustic spectroscopy measurements were performed for TiO2 -NR HOMCs and FeOx /TiO2 -NR HOMCs to obtain the ERDT (energy-resolved distribution of electron traps)/CBB (conduction-band bottom) patterns. The ERDT/CBB pattern of TiO2 -NR HOMCs consists of two components derived from rutile (C1) and amorphous TiO2 (C2). In the pattern, the surface electron traps in C2 exist near the CBB to be removed by the FeOx -surface modification. By taking this finding into consideration, the striking surface modification effect is ascribable to the electrocatalytic activity (or the action as an electron reservoir) of the FeOx clusters for multiple ORR, the suppression of recombination, and the increase in the visible-light harvesting efficiency.
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Affiliation(s)
- Ryota Kojima
- Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, 577-8502, Higashi-Osaka, Osaka, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, 060-0810, Sapporo, Hokkaido, Japan.,Institute for Catalysis, Hokkaido University, 001-0021, Sapporo, Hokkaido, Japan
| | - Hiroaki Tada
- Graduate School of Science and Engineering, Kindai University, 3-4-1, Kowakae, 577-8502, Higashi-Osaka, Osaka, Japan
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10
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Fabrication of Adsorbed Fe(III) and Structurally Doped Fe(III) in Montmorillonite/TiO2 Composite for Photocatalytic Degradation of Phenol. MINERALS 2021. [DOI: 10.3390/min11121381] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The Fe(III)-doped montmorillonite (Mt)/TiO2 composites were fabricated by adding Fe(III) during or after the aging of TiO2/Ti(OH)4 sol–gel in Mt, named as xFe-Mt/(1 − x)Fe-TiO2 and Fe/Mt/TiO2, respectively. In the xFe-Mt/(1 − x)Fe-TiO2, Fe(III) cations were expected to be located in the structure of TiO2, in the Mt, and in the interface between them, while Fe(III) ions are physically adsorbed on the surfaces of the composites in the Fe/Mt/TiO2. The narrower energy bandgap (Eg) lower photo-luminescence intensity were observed for the composites compared with TiO2. Better photocatalytic performance for phenol degradation was observed in the Fe/Mt/TiO2. The 94.6% phenol degradation was due to greater charge generation and migration capacity, which was confirmed by photocurrent measurements and electrochemical impedance spectroscopy (EIS). The results of the energy-resolved distribution of electron traps (ERDT) suggested that the Fe/Mt/TiO2 possessed a larger amorphous rutile phase content in direct contact with crystal anatase than that of the xFe-Mt/(1 − x)Fe-TiO2. This component is the fraction that is mainly responsible for the photocatalytic phenol degradation by the composites. As for the xFe-Mt/(1 − x)Fe-TiO2, the active rutile phase was followed by isolated amorphous phases which had larger (Eg) and which did not act as a photocatalyst. Thus, the physically adsorbed Fe(III) enhanced light adsorption and avoided charge recombination, resulting in improved photocatalytic performance. The mechanism of the photocatalytic reaction with the Fe(III)-doped Mt/TiO2 composite was proposed.
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11
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Sudrajat H, Kitta M, Ito R, Yoshida T, Katoh R, Ohtani B, Ichikuni N, Onishi H. The role of the shell in core-shell-structured La-doped NaTaO 3 photocatalysts. Phys Chem Chem Phys 2021; 23:8868-8879. [PMID: 33876046 DOI: 10.1039/d1cp00375e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
NaTaO3, a semiconductor with a perovskite structure, has long been known as a highly active photocatalyst for overall water splitting when appropriately doped with La cations. A profound understanding of the surface feature and why and how it may control the water splitting activity is critical because redox reactions take place at the surface. One surface feature characteristic of La-doped NaTaO3 is a La-rich layer (shell) capping La-poor bulk (core). In this study, we investigate the role of the shell in core-shell-structured La-doped NaTaO3 through systematic chemical etching with an aqueous HF solution. We find that the La-rich shell plays a role in electron-hole recombination, electron mobility and water splitting activity. The shallow electron traps populating the La-rich shell trap the photoexcited electrons, decreasing their mobility. The shallowly trapped electrons remain reactive and are readily available on the surface to be extracted by the cocatalysts for the reduction reaction evolving H2. The presently employed chemical etching method also confirms the presence of a La concentration gradient in the core that regulates the steady-state electron population and water splitting activity. Here, we successfully reveal the nanoarchitecture-photoactivity relationship of core-shell-structured La-doped NaTaO3 that thereby allows tuning of the surface features and spatial distribution of dopants to increase the concentration of photoexcited electrons and therefore the water splitting activity. By recognizing the key factors that control the photocatalytic properties of a highly active catalyst, we can then devise proper strategies to design new photocatalyst materials with breakthrough performances.
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Affiliation(s)
- Hanggara Sudrajat
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe 657-8501, Japan
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12
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Chen G, Takashima M, Ohtani B. Direct Amorphous-structure Analysis: How are Surface/Bulk Structure and Activity of Titania Photocatalyst Particles Changed by Milling? CHEM LETT 2021. [DOI: 10.1246/cl.200825] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Guangyi Chen
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Mai Takashima
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
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13
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Kobielusz M, Nitta A, Macyk W, Ohtani B. Combined Spectroscopic Methods of Determination of Density of Electronic States: Comparative Analysis of Diffuse Reflectance Spectroelectrochemistry and Reversed Double-Beam Photoacoustic Spectroscopy. J Phys Chem Lett 2021; 12:3019-3025. [PMID: 33733790 PMCID: PMC8041308 DOI: 10.1021/acs.jpclett.1c00262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/04/2021] [Indexed: 06/12/2023]
Abstract
The diffuse reflectance spectroelectrochemistry (SE-DRS) and reversed double-beam photoacoustic spectroscopy (RDB-PAS) provide unique, complementary information on the density of electronic states (DOS) in the vicinity of the conduction band bottom. The measurements are performed under quite different conditions, representing the solid/liquid and solid/gas interfaces in SE-DRS and RDB-PAS, respectively. DOS profiles obtained from both types of measurements can be considered as unique "fingerprints" of the tested materials. The analysis of DOS profiles recorded for 16 different TiO2 samples confirms that both methods similarly describe the shapes of DOS profiles around the conduction band edges. The states characterized by energy higher than VBT (valence-band top) + Eg can be considered as electronic states within the conduction band. Recognition of the potential of the conduction band bottom allows one to classify the electronic states as deep or shallow electron traps or conduction band states, which play different roles in photocatalysis. The comparative analysis shows that both methods provide very useful information which can be used in understanding and predicting the photo(electro)catalytic reactivity of semiconductors.
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Affiliation(s)
- Marcin Kobielusz
- Faculty
of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Kraków, Poland
| | - Akio Nitta
- Institute
for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
- Graduate
School of Environmental Science, Hokkaido
University, Sapporo 060-0810, Japan
| | - Wojciech Macyk
- Faculty
of Chemistry, Jagiellonian University, ul. Gronostajowa 2, 30-387 Kraków, Poland
| | - Bunsho Ohtani
- Institute
for Catalysis, Hokkaido University, Sapporo 001-0021, Japan
- Graduate
School of Environmental Science, Hokkaido
University, Sapporo 060-0810, Japan
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14
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Shen Y, Nitta A, Takashima M, Ohtani B. Do Particles Interact Electronically? —Proof of Interparticle Charge-transfer Excitation between Adjoined Anatase and Rutile Particles. CHEM LETT 2021. [DOI: 10.1246/cl.200636] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Yang Shen
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Akio Nitta
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
| | - Mai Takashima
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Institute for Catalysis, Hokkaido University, Sapporo, Hokkaido 001-0021, Japan
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15
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Wang C, Zhang X. Anatase/Bronze TiO2 Heterojunction: Enhanced Photocatalysis and Prospect in Photothermal Catalysis. Chem Res Chin Univ 2020. [DOI: 10.1007/s40242-020-0312-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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16
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Sano K, Kuttassery F, Shimada T, Ishida T, Takagi S, Ohtani B, Yamakata A, Honma T, Tachibana H, Inoue H. Optically Transparent Colloidal Dispersion of Titania Nanoparticles Storable for Longer than One Year Prepared by Sol/Gel Progressive Hydrolysis/Condensation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:44743-44753. [PMID: 32915534 DOI: 10.1021/acsami.0c12951] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The molecular catalyst sensitized system (MCSS), where an excited molecular catalyst adsorbed on a semiconductor such as TiO2 injects electrons to the conduction band of the semiconductor leading to hydrogen evolution/CO2 reduction coupled with an oxidation of water on the molecular catalyst, has been one of the most probable candidates in the approach to artificial photosynthesis. For a full utilization of visible light, however, a serious light scattering of the aqueous suspension of TiO2 in the visible region, which is generally experienced, should be avoided. Here, we report a preparation of optically transparent colloidal dispersion of TiO2 by the sol/gel reaction of TiCl4 through progressive hydrolysis/condensation under the basic condition without any calcination processes. The TiO2 nanoparticles (TiO2(NPs)) obtained were characterized as an amorphous particle (∼10-15 nm) having a microcrystal domain of anatase within several nm by XRD, Raman spectroscopies, XRF, XAFS, TG/DTA, and HRTEM, respectively. The energy-resolved distribution of carrier electron traps in TiO2(NPs) as a fingerprint of TiO2 was characterized through reversed double-beam photo-acoustic spectroscopy to have a close similarity to that of TiO2(ST-01) as well as the observation of carrier traps by transient absorption spectroscopy. Though the powder TiO2(NP) itself was not dispersed well in aqueous solution, the wet TiO2(NPs) as prepared before being dried up provided a completely transparent aqueous dispersion under the acidic condition (1 M HCl). Addition of methanol enabled the colloidal dispersion (TiO2(NPs, MeOH/H2O, 0.1 M HCl)) to keep the optical transparency for longer than 1 year (550 days), which is the first example of TiO2 dispersion storable for such a long period. TiO2(NPs, MeOH/H2O) exhibited a moderate photocatalytic reactivity of H2 evolution with a quantum yield of ∼2.6% upon 365 nm light irradiation. An optically transparent thin film of TiO2(NPs, MeOH/H2O) was also successfully prepared on a glass plate to exhibit an enhanced hydrophilicity upon UV light irradiation.
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Affiliation(s)
- Keito Sano
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Fazalurahman Kuttassery
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Tetsuya Shimada
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Tamao Ishida
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Shinsuke Takagi
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Bunsho Ohtani
- Institute for catalysis Hokkaido University, North 21, West 10, Sapporo 001-0021, Japan
| | - Akira Yamakata
- Toyota Technological Institute, 2-12-1, Hisakata, Tempaku, Nagoya 468-8511, Japan
| | - Tetsuo Honma
- Japan Synchrotron Radiation Research Institute (JASRI), 1-1-1 Kouto, Sayo, Hyogo 679-5198, Japan
| | - Hiroshi Tachibana
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
| | - Haruo Inoue
- Department of Applied Chemistry for Environment, Graduate School of Urban Environmental Sciences, Tokyo Metropolitan University, 1-1 Minami-ohsawa, Hachiohji, Tokyo 192-0397, Japan
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17
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Yu F, Wang C, Li Y, Ma H, Wang R, Liu Y, Suzuki N, Terashima C, Ohtani B, Ochiai T, Fujishima A, Zhang X. Enhanced Solar Photothermal Catalysis over Solution Plasma Activated TiO 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000204. [PMID: 32832348 PMCID: PMC7435248 DOI: 10.1002/advs.202000204] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/25/2020] [Indexed: 05/22/2023]
Abstract
Colored wide-bandgap semiconductor oxides with abundant mid-gap states have long been regarded as promising visible light responsive photocatalysts. However, their catalytic activities are hampered by charge recombination at deep level defects, which constitutes the critical challenge to practical applications of these oxide photocatalysts. To address the challenge, a strategy is proposed here that includes creating shallow-level defects above the deep-level defects and thermal activating the migration of trapped electrons out of the deep-level defects via these shallow defects. A simple and scalable solution plasma processing (SPP) technique is developed to process the presynthesized yellow TiO2 with numerous oxygen vacancies (Ov), which incorporates hydrogen dopants into the TiO2 lattice and creates shallow-level defects above deep level of Ov, meanwhile retaining the original visible absorption of the colored TiO2. At elevated temperature, the SPP-treated TiO2 exhibits a 300 times higher conversion rate for CO2 reduction under solar light irradiation and a 7.5 times higher removal rate of acetaldehyde under UV light irradiation, suggesting the effectiveness of the proposed strategy to enhance the photoactivity of colored wide-bandgap oxides for energy and environmental applications.
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Affiliation(s)
- Fei Yu
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Changhua Wang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Yingying Li
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - He Ma
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Rui Wang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Yichun Liu
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
| | - Norihiro Suzuki
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Chiaki Terashima
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Bunsho Ohtani
- Graduate School of Environmental ScienceHokkaido UniversitySapporo060‐0810Japan
| | - Tsuyoshi Ochiai
- Materials Analysis GroupKawasaki Technical Support DepartmentLocal Independent Administrative Agency Kanagawa Institute of industrial Science and Technology (KISTEC)Kanagawa213‐0012Japan
| | - Akira Fujishima
- Photocatalysis International Research CenterResearch Institute for Science & TechnologyTokyo University of Science2641 YamazakiNodaChiba278‐8510Japan
| | - Xintong Zhang
- Key Laboratory of UV‐Emitting Materials and Technology of Chinese Ministry of EducationNortheast Normal UniversityChangchun130024China
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18
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Nagakawa H, Ochiai T, Ma H, Wang C, Zhang X, Shen Y, Takashima M, Ohtani B, Nagata M. Elucidation of the electron energy structure of TiO 2(B) and anatase photocatalysts through analysis of electron trap density. RSC Adv 2020; 10:18496-18501. [PMID: 35517202 PMCID: PMC9053729 DOI: 10.1039/d0ra02587a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/07/2020] [Indexed: 11/21/2022] Open
Abstract
A clear understanding of the electron energy structure of TiO2(B)/anatase is needed to study the related catalytic reactions and design new composite photocatalysts. In this study, the electron energy structures of TiO2(B) and anatase were estimated by analyzing the energy-resolved distribution of electron traps measured by reversed double-beam photoacoustic spectroscopy. In the mixture of TiO2(B) and anatase, interfacial charge-transfer excitation from anatase to electron traps of TiO2(B) was suggested. By analyzing this for TiO2(B), the electron level with a relatively high density of states was found to be located ∼0.07 eV deeper than that for anatase. Furthermore, a similar electron energy structure was suggested for a composite photocatalyst having a mixed phase of TiO2(B) and anatase. The electron energy structures of TiO2(B) and anatase were estimated by analyzing the energy-resolved distribution of electron traps.![]()
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Affiliation(s)
- Haruki Nagakawa
- Department of Industrial Chemistry, Graduate School of Engineering, Tokyo University of Science 12-1 Ichigayafunagawara-cho, Shinjuku-ku Tokyo 162-0826 Japan
| | - Tsuyoshi Ochiai
- Materials Analysis Group, Research and Development Department, Local Independent Administrative Agency, Kanagawa Institute of industrial Science and TEChnology (KISTEC) Kanagawa 213-0012 Japan.,Photocatalysis International Research Center, Tokyo University of Science Chiba 278-8510 Japan
| | - He Ma
- Center for Advanced Optoelectronic Functional Materials Research, Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University Changchun 130024 China
| | - Changhua Wang
- Center for Advanced Optoelectronic Functional Materials Research, Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University Changchun 130024 China
| | - Xintong Zhang
- Center for Advanced Optoelectronic Functional Materials Research, Key Laboratory of UV-Emitting Materials and Technology of Ministry of Education, Northeast Normal University Changchun 130024 China
| | - Yang Shen
- Graduate School of Environmental Science, Hokkaido University Sapporo 060-0810 Japan
| | - Mai Takashima
- Graduate School of Environmental Science, Hokkaido University Sapporo 060-0810 Japan.,Institute for Catalysis, Hokkaido University Sapporo 001-0021 Japan +81-11-706-9133
| | - Bunsho Ohtani
- Graduate School of Environmental Science, Hokkaido University Sapporo 060-0810 Japan.,Institute for Catalysis, Hokkaido University Sapporo 001-0021 Japan +81-11-706-9133
| | - Morio Nagata
- Department of Industrial Chemistry, Graduate School of Engineering, Tokyo University of Science 12-1 Ichigayafunagawara-cho, Shinjuku-ku Tokyo 162-0826 Japan
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19
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Chuaicham C, Karthikeyan S, Pawar RR, Xiong Y, Dabo I, Ohtani B, Kim Y, Song JT, Ishihara T, Sasaki K. Energy-resolved distribution of electron traps for O/S-doped carbon nitrides by reversed double-beam photoacoustic spectroscopy and the photocatalytic reduction of Cr(vi). Chem Commun (Camb) 2020; 56:3793-3796. [PMID: 32129327 DOI: 10.1039/c9cc09988c] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report for the first time to our knowledge the identification of heteroatom-doped and undoped C3N4 with the energy-resolved distribution of electron traps (ERDT) near the conduction band bottom position (CBB) using reversed double-beam photoacoustic spectroscopy. The ERDT/CBB pattern is used to classify the type of elemental doping in C3N4, related to photocatalytic efficiency.
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Affiliation(s)
- Chitiphon Chuaicham
- Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishiku, Fukuoka 819-0395, Japan.
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20
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Yu F, Wang C, Ma H, Song M, Li D, Li Y, Li S, Zhang X, Liu Y. Revisiting Pt/TiO 2 photocatalysts for thermally assisted photocatalytic reduction of CO 2. NANOSCALE 2020; 12:7000-7010. [PMID: 32103213 DOI: 10.1039/c9nr09743k] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Artificial photosynthesis by a semiconductor-oxide-based photocatalysis is presently challenging due to low CO2 conversion rates and poor product selectivity. To promote CO2 reduction, Pt/TiO2 has been deemed as a classic photocatalyst. In this study, we restudy Pt/TiO2 for the thermally assisted photocatalytic reduction of CO2 and reveal a different story between photocatalysis and photothermal catalysis. For example, when using disordered Pt/TiO2-x, the CO2 conversion via photocatalysis at 298 K is not impressive. However, when the system temperature is increased to 393 K, the CO2 conversion rate is significantly enhanced by a factor of 155 as compared to that obtainable from pristine TiO2; further, surprisingly high selectivity of CH4 (87.5%) could be achieved. Thermally coupled photocatalysis yields the enhanced evolution of H2 side products over Pt (4.06 nm)/TiO2 and promoted H2 splitting over Pt (2.33 nm)/TiO2, which is seldom observed in conventional Pt/TiO2 photocatalysis. The synergy of improved charge separation at the Pt/TiO2-x interface induced by surface disordering and accelerated H2 consumption near smaller Pt nanoparticles by thermal assistance are believed to be critically important for the simultaneous enhancement of CO2 conversion rates and CH4 product selectivity. This study inspires revisiting not only Pt/TiO2 but also reactivating other semiconductor-oxide-based photocatalysts for use in thermally assisted photocatalysis.
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Affiliation(s)
- Fei Yu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China.
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21
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Correlation of the Photocatalytic Activities of Cu, Ce and/or Pt-Modified Titania Particles with their Bulk and Surface Structures Studied by Reversed Double-Beam Photoacoustic Spectroscopy. Catalysts 2019. [DOI: 10.3390/catal9121010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Modified titania photocatalyst powder samples were prepared using the sol-gel method for copper (Cu) and cerium (Ce) doping and impregnation for platinum (Pt) loading. Their bulk crystalline structures were investigated using X-ray diffractometry (XRD) with the Rietveld analysis. The surface/bulk structure, surface properties, and morphologies were observed using reversed double-beam photoacoustic spectroscopy (RDB-PAS), nitrogen adsorption, and scanning electron microscopy, respectively. The results from the XRD revealed that all samples were mainly anatase (ca. 80% or higher) with small amounts of rutile and non-crystalline components. The specific surface areas of all samples were in the range of 115–155 m2 g−1. Ce and Cu species were mainly distributed, while Pt was potentially loaded as a partially oxidized form on the titania surface. The results from the RDB-PAS indicated the changing of the energy-resolved distribution of electron traps (ERDT) from the original titania surface upon doping of the metals (Cu, Ce, and Pt), which altered their catalytic activities. The metals photocatalytic activities with UV irradiation were measured in two representative reactions; (a) CO2 evolution from acetic acid under the aerobic condition and (b) H2 evolution from deaerated aqueous methanol. In reaction (a), the Cu and/or Ce modification gave almost the same or slightly lower activity compared to the non-modified titania samples, while platinum loading yielded ca. 5–6 times higher activity. For reaction (b), the photocatalytic tests were divided into two sets; without (b1) and with (b2) Pt deposition during the reaction. Similar enhancements of activity from the Pt loading sample (and by Cu modification) were observed in reaction (b1) without in-situ platinum deposition, while the unmodified and Ce-doped samples were almost inactive. For the activities of reaction (b2) with in-situ platinum deposition, the unmodified samples showed the highest activity while the Cu-modified samples showed significantly lower activity.
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22
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Kavan L. Conduction band engineering in semiconducting oxides (TiO2, SnO2): Applications in perovskite photovoltaics and beyond. Catal Today 2019. [DOI: 10.1016/j.cattod.2018.10.065] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Maitani MM, Tateyama A, Boix PP, Han G, Nitta A, Ohtani B, Mathews N, Wada Y. Effects of energetics with {001} facet-dominant anatase TiO2 scaffold on electron transport in CH3NH3PbI3 perovskite solar cells. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.01.102] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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24
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OHTANI B. Physicochemical Mechanistic Studies on Photocatalysis–Extension of Semiconductor Photoelectrochemistry Concept beyond Its Limitation. ELECTROCHEMISTRY 2018. [DOI: 10.5796/electrochemistry.18-6-e2667] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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25
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Cheng K, Chhor K, Passarello JP, Colbeau-Justin C, Kanaev A. Photocatalytic Nanoparticulate Zr x
Ti 1-x
O 2
Coatings with Controlled Homogeneity of Elemental Composition. ChemistrySelect 2018. [DOI: 10.1002/slct.201801732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Khley Cheng
- Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité; 93430 Villetaneuse France
| | - Khay Chhor
- Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité; 93430 Villetaneuse France
| | - Jean-Philippe Passarello
- Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité; 93430 Villetaneuse France
| | | | - Andrei Kanaev
- Laboratoire des Sciences des Procédés et des Matériaux, CNRS, Université Paris 13, Sorbonne Paris Cité; 93430 Villetaneuse France
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