1
|
A V N, V M A, V B. Band alignment and interfacial charge transfer in sol-gel derived anatase/rutile heterophase TiO 2: explaining the synergistic photocatalytic activity. Phys Chem Chem Phys 2024; 26:13937-13948. [PMID: 38668752 DOI: 10.1039/d4cp00729h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024]
Abstract
In this study, we have synthesized nanostructured titanium dioxide (TiO2) photocatalysts under different configurations, viz., anatase, rutile and anatase/rutile heterophase (Eg = 3.14-2.96 eV) through a sol-gel route. The photocatalytic performance of the heterophase samples was better than that of their phase-pure counterparts. Photocatalytic performance was maximum for sample T12H (50% rutile) with a rate constant, k = (7.38 ± 1.48) × 10-2 min-1. This is ca. 47% greater than that estimated via an extrapolation method using the values for phase pure samples indicating synergistic effects. High-resolution transmission electron microscope (HRTEM) analysis and the phase-dependent broadening of core-level X-ray photoelectron spectroscopy (XPS) analysis indicate the formation of well-defined anatase/rutile interfaces. Interfacial charge transfer is the critical factor for this synergistic effect. To analyze the charge transfer pathways, the possible band alignment scheme was analyzed through the precise determination of band alignments from XPS, employing the Ti 2p3/2 core level as a reference. We found a staggered rutile band alignment with the valence band edge of rutile lying above that of anatase, indicating the transfer of photogenerated free electrons from the conduction band of rutile to that of anatase and hole transfer from the valence band of anatase to rutile. These inferences are validated through Mott-Schottky analysis as well.
Collapse
Affiliation(s)
- Nimmy A V
- Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala, 695581, India.
| | - Anandakumar V M
- Department of Physics, Mahatma Gandhi College, Thiruvananthapuram, Kerala, 695004, India
- Department of Physics, VTMNSS College Dhanuvachapuram, Thiruvananthapuram, Kerala, 695503, India
| | - Biju V
- Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram, Kerala, 695581, India.
| |
Collapse
|
2
|
Bossard-Giannesini L, Cardenas L, Cruguel H, Demessence A, Loffreda D, Pluchery O. How far the chemistry of self-assembled monolayers on gold surfaces affects their work function? NANOSCALE 2023; 15:17113-17123. [PMID: 37850381 DOI: 10.1039/d3nr03172a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Self-assembled monolayers composed of various long-chain aliphatic molecules and different tail functional groups have been synthesized on the Au(111) surface and characterized by Kelvin probe force microscopy and ultraviolet photoelectron spectroscopy. Carboxy, amino, thio and methyl terminal groups have been considered in the design of self-assembled monolayers with different aliphatic chain lengths (from C6 to C16). Work function measurements by Kelvin probe force microscopy have been carried out under a controlled and room atmosphere. Remarkably, a reduction of the relative humidity from 40% to 3% has induced a work function shift of up to 0.3 eV. As expected, the changes of the chain length of the aliphatic moiety and of the tail group have a significant impact on the tuning of the measured work function (3.90 eV for dodecanethiol versus 4.57 eV for mercaptohexadecylamine). Surprisingly, the change of the net dipole moment of the tail group (sign and amplitude) does not dominate the work function variations. In contrast, the change of the chain length and the possibility of the tail group to form a complex hydrogen bond network between molecules lead to significant modulations of the work function. In order to interpret these original findings, density functional theory models of equivalent self-assembled monolayers adsorbed on the Au(111) surface have been developed at an unprecedented level of description with large supercells including simultaneously 27 co-adsorbed molecules and weak van der Waals interactions between them. Such large systems have allowed the theoretical modeling of complex hydrogen bond networks between molecules when possible (carboxy tail group). The comparison between computed and measured work functions shows a striking agreement, thus allowing the disentanglement of the previously mentioned competing effects. This consistency between experiment and theory will help in designing the electronic properties of self-assembled monolayers in the context of molecular electronics and organic transistors.
Collapse
Affiliation(s)
- Léo Bossard-Giannesini
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
| | - Luis Cardenas
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON - UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France
| | - Hervé Cruguel
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
| | - Aude Demessence
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON - UMR 5256, 2 Avenue Albert Einstein, 69626 Villeurbanne, France
| | - David Loffreda
- ENSL, CNRS, Laboratoire de Chimie UMR 5182, 46 Allée d'Italie, 69364 Lyon Cedex, France.
| | - Olivier Pluchery
- Institut des NanoSciences de Paris, UMR7588 CNRS Sorbonne Université, 4 place Jussieu, 75005 Paris, France.
| |
Collapse
|
3
|
Pu Y, Jia L, Huang Q, Tang X, Rodriguez P, Huang L. Investigation on the surface charge separation in Pt-supported morphology-related-TiO 2 and its effect on water splitting. J Colloid Interface Sci 2023; 646:815-823. [PMID: 37229999 DOI: 10.1016/j.jcis.2023.05.104] [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: 03/10/2023] [Revised: 05/11/2023] [Accepted: 05/16/2023] [Indexed: 05/27/2023]
Abstract
Lowering Pt loading in the catalyst while maintaining its superior catalytic efficiency during hydrogen evolution reaction (HER) is essential for the large-scale application of water splitting. The utilization of strong metal-support interaction (SMSI) through morphology engineering has emerged as an effective strategy in fabricating Pt-supported catalysts. However, a simple and explicit routine to realize the rational design of morphology-related SMSI remains challenging. Here we report a protocol for the photochemical deposition of Pt, which benefits from the intrinsic difference in absorption capability of TiO2 to establish proper Pt+ species and charge separation domains on the surface. With a comprehensive investigation of the surface environment through experiments and Density functional theory (DFT) calculations, charge transfer from Pt to Ti, the separation of electron-hole pairs, and the enhanced electron transfer in the TiO2 matrix were confirmed. It is reported that H2O molecules can be spontaneously dissociated by the surface Ti and O, generating OH stabilized by adjacent Ti and Pt. Such adsorbed OH group induces changes in the electron density of Pt, consequently favours the H adsorption and enhances the HER. Benefiting from the preferable electronic state, the annealed Pt@TiO2-pH9 (PTO-pH9@A) exhibits an overpotential of 30 mV to reach 10 mA cm-2 geo and a mass activity of 3954 A g-1Pt, which is 17-fold higher than the commercial Pt/C. Our work provides a new strategy for the high-efficient catalyst design by the surface state- regulated SMSI.
Collapse
Affiliation(s)
- Yayun Pu
- School of Optoelectronic Engineering, Chongqing University of Post and Telecommunication, No. 2, Chongwen Road, Chongqing 400065, China; Department of Chemistry, Southern University of Science and Technology, No. 1088, Xueyuan Blvd, Shenzhen, Guangdong 518055, China; School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Lu Jia
- Department of Chemistry, Southern University of Science and Technology, No. 1088, Xueyuan Blvd, Shenzhen, Guangdong 518055, China
| | - Qiang Huang
- School of Optoelectronic Engineering, Chongqing University of Post and Telecommunication, No. 2, Chongwen Road, Chongqing 400065, China
| | - Xiaosheng Tang
- School of Optoelectronic Engineering, Chongqing University of Post and Telecommunication, No. 2, Chongwen Road, Chongqing 400065, China
| | - Paramaconi Rodriguez
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; Centre for Cooperative Research on Alternative Energies (CICenergiGUNE), Basque Research and Technology Alliance (BRTA), Alava Technology Park, 01510 Vitoria-Gasteiz, Spain; IKERBASQUE, Basque Foundation for Science, Plaza de Euskadi 5, 48009 Bilbao, Spain.
| | - Limin Huang
- Department of Chemistry, Southern University of Science and Technology, No. 1088, Xueyuan Blvd, Shenzhen, Guangdong 518055, China; Guangdong-Hong Kong-Macao Joint Laboratory for Photonic-Thermal-Electrical Energy Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China.
| |
Collapse
|
4
|
Ciria-Ramos I, Juarez-Perez EJ, Haro M. Solar Energy Storage Using a Cu 2 O-TiO 2 Photocathode in a Lithium Battery. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023:e2301244. [PMID: 37010019 DOI: 10.1002/smll.202301244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Indexed: 06/19/2023]
Abstract
A Cu2 O-TiO2 photoelectrode is pr+oposed for simultaneous solar light energy harvesting and storing of electrochemical energy in an adapted lithium coin cell. The p-type Cu2 O semiconductor layer is the light harvester component of the photoelectrode and the TiO2 film performs as the capacitive layer. The rationale of the energy scheme shows that the photocharges generated in the Cu2 O semiconductor induce lithiation/delithiation processes in the TiO2 film as a function of the applied bias voltage and light power. A photorechargeable lithium button cell drilled on one side recharges with visible white light in ≈9 h in open circuit. It provides an energy density of ≈150 mAh g-1 at 0.1 C discharge current in dark, and the overall efficiency is 0.29%. This work draws a new approach for the photoelectrode role to advance in monolithic rechargeable batteries.
Collapse
Affiliation(s)
- Isabel Ciria-Ramos
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, 50009, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, Plaza San Francisco, Zaragoza, 50009, Spain
| | - Emilio J Juarez-Perez
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, 50009, Spain
- Aragonese Foundation for Research and Development (ARAID), Government of Aragon, Zaragoza, 50018, Spain
| | - Marta Haro
- Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza, 50009, Spain
- Departamento de Química Física, Facultad de Ciencias, Universidad de Zaragoza, Plaza San Francisco, Zaragoza, 50009, Spain
| |
Collapse
|
5
|
Castro-Godoy WD, Schmidt LC, Flores-Oña D, Pérez-Prieto J, Galian RE, Argüello JE. Linker-Assisted CdS-TiO 2 Nanohybrids as Reusable Visible Light Photocatalysts for the Oxidative Hydroxylation of Arylboronic Acids. J Org Chem 2023; 88:6489-6497. [PMID: 36930860 DOI: 10.1021/acs.joc.2c02964] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
A variety of phenols have been obtained in aqueous media with moderate to excellent chemical yields (≤100%) by using arylboronic acids and esters as substrates, a robust CdS-TiO2 nanohybrid as a heterogeneous photocatalyst, visible light irradiation (467 nm), and an O2-saturated atmosphere. The nanohybrid was prepared through a linker-assisted methodology that uses mercapto alkanoic acids as the organic linkers. The nanohybrid showed improved photocatalytic activity in the hydroxylation of substituted arylboronic acids and phenyl boronic esters compared with that of pristine CdS quantum dots. The nanohybrid can be reused in up to five photocatalytic cycles with ∼90% of its outstanding activity preserved.
Collapse
Affiliation(s)
- Willber D Castro-Godoy
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina.,CENSALUD-UES, Departamento de Química, Física y Matemática, Facultad de Química y Farmacia, Universidad de El Salvador, Final Av. Mártires y Héroes del 30 de Julio, San Salvador 1101, El Salvador
| | - Luciana C Schmidt
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina.,Instituto de Tecnología Química, Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avenida de los Naranjos s/n, 46022 Valencia, Spain
| | - Diego Flores-Oña
- Institute of Molecular Science (ICMol), University of Valencia, Catedrático José Beltrán 2, Paterna 46980, Valencia, Spain.,Facultad de Ingeniería Química Universidad Central de Ecuador, Rither y Bolivia, Ciudadela Universitaria, 170521 Quito, Ecuador
| | - Julia Pérez-Prieto
- Institute of Molecular Science (ICMol), University of Valencia, Catedrático José Beltrán 2, Paterna 46980, Valencia, Spain
| | - Raquel E Galian
- Institute of Molecular Science (ICMol), University of Valencia, Catedrático José Beltrán 2, Paterna 46980, Valencia, Spain
| | - Juan E Argüello
- INFIQC-CONICET-UNC, Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA Córdoba, Argentina
| |
Collapse
|
6
|
Wang C, Li X, Ren Y, Jiao H, Wang FR, Tang J. Synergy of Ag and AgBr in a Pressurized Flow Reactor for Selective Photocatalytic Oxidative Coupling of Methane. ACS Catal 2023; 13:3768-3774. [PMID: 36970465 PMCID: PMC10028603 DOI: 10.1021/acscatal.2c06093] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/05/2023] [Indexed: 03/06/2023]
Abstract
Oxidation of methane into valuable chemicals, such as C2+ molecules, has been long sought after but the dilemma between high yield and high selectivity of desired products remains. Herein, methane is upgraded through the photocatalytic oxidative coupling of methane (OCM) over a ternary Ag-AgBr/TiO2 catalyst in a pressurized flow reactor. The ethane yield of 35.4 μmol/h with a high C2+ selectivity of 79% has been obtained under 6 bar pressure. These are much better than most of the previous benchmark performance in photocatalytic OCM processes. These results are attributed to the synergy between Ag and AgBr, where Ag serves as an electron acceptor and promotes the charge transfer and AgBr forms a heterostructure with TiO2 not only to facilitate charge separation but also to avoid the overoxidation process. This work thus demonstrates an efficient strategy for photocatalytic methane conversion by both the rational design of the catalyst for the high selectivity and reactor engineering for the high conversion.
Collapse
Affiliation(s)
- Chao Wang
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
| | - Xiyi Li
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
| | - Yifei Ren
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
| | - Haimiao Jiao
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
| | - Feng Ryan Wang
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
| | - Junwang Tang
- Department of Chemical Engineering, University College London, London WC1E 7JE, U.K
- Industrial Catalysis Center, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| |
Collapse
|
7
|
Chen X, Huan Y, Sun N, Su Y, Shen X, Li G, Zhang J, Wei T. Studying the variable energy band structure for energy storage materials in charge/discharge process. CHINESE CHEM LETT 2023. [DOI: 10.1016/j.cclet.2023.108380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
|
8
|
Sonström A, Boldrini B, Werner D, Maichle-Mössmer C, Rebner K, Casu MB, Anwander R. Titanium(IV) Surface Complexes Bearing Chelating Catecholato Ligands for Enhanced Band-Gap Reduction. Inorg Chem 2023; 62:715-729. [PMID: 36595489 DOI: 10.1021/acs.inorgchem.2c02838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Protonolysis reactions between dimethylamido titanium(IV) catecholate [Ti(CAT)(NMe2)2]2 and neopentanol or tris(tert-butoxy)silanol gave catecholato-bridged dimers [(Ti(CAT)(OCH2tBu)2)(HNMe2)]2 and [Ti(CAT){OSi(OtBu)3}2(HNMe2)2]2, respectively. Analogous reactions using the dimeric dimethylamido titanium(IV) (3,6-di-tert-butyl)catecholate [Ti(CATtBu2-3,6)(NMe2)2]2 yielded the monomeric Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 and Ti(CATtBu2-3,6)[OSi(OtBu)3]2(HNMe2)2. The neopentoxide complex Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2 engaged in further protonolysis reactions with Si-OH groups and was consequentially used for grafting onto mesoporous silica KIT-6. Upon immobilization, the surface complex [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[KIT-6] retained the bidentate chelating geometry of the catecholato ligand. This convergent grafting strategy was compared with a sequential and an aqueous approach, which gave either a mixture of bidentate chelating species with a bipodally anchored Ti(IV) center along with other physisorbed surface species or not clearly identifiable surface species. Extension of the convergent and aqueous approaches to anatase mesoporous titania (m-TiO2) enabled optical and electronic investigations of the corresponding surface species, revealing that the band-gap reduction is more pronounced for the bidentate chelating species (convergent approach) than for that obtained via the aqueous approach. The applied methods include X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and solid-state UV/vis spectroscopy. The energy-level alignment for the surface species from the aqueous approach, calculated from experimental data, accounts for the well-known type II excitation mechanism, whereas the findings indicate a distinct excitation mechanism for the bidentate chelating surface species of the material [Ti(CATtBu2-3,6)(OCH2tBu)2(HNMe2)2]@[m-TiO2].
Collapse
Affiliation(s)
- Andrea Sonström
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Barbara Boldrini
- Lehr- und Forschungszentrum "Process Analysis and Technology", Fakultät Angewandte Chemie, Hochschule Reutlingen, Alteburgstraße 150, Reutlingen 72762, Germany
| | - Daniel Werner
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Cäcilia Maichle-Mössmer
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Karsten Rebner
- Lehr- und Forschungszentrum "Process Analysis and Technology", Fakultät Angewandte Chemie, Hochschule Reutlingen, Alteburgstraße 150, Reutlingen 72762, Germany
| | - Maria Benedetta Casu
- Institut für Physikalische und Theoretische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| | - Reiner Anwander
- Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, Tübingen 72076, Germany
| |
Collapse
|
9
|
Debgupta J, Lari L, Isaacs M, Carey J, McKenna KP, Lazarov VK, Chechik V, Douthwaite RE. Predictive Removal of Interfacial Defect-Induced Trap States between Titanium Dioxide Nanoparticles via Sub-Monolayer Zirconium Coating. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:660-671. [PMID: 36660098 PMCID: PMC9841567 DOI: 10.1021/acs.jpcc.2c06927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/13/2022] [Indexed: 06/17/2023]
Abstract
First principles modeling of anatase TiO2 surfaces and their interfacial contacts shows that defect-induced trap states within the band gap arise from intrinsic structural distortions, and these can be corrected by modification with Zr(IV) ions. Experimental testing of these predictions has been undertaken using anatase nanocrystals modified with a range of Zr precursors and characterized using structural and spectroscopic methods. Continuous-wave electron paramagnetic resonance (EPR) spectroscopy revealed that under illumination, nanoparticle-nanoparticle interfacial hole trap states dominate, which are significantly reduced after optimizing the Zr doping. Fabrication of nanoporous films of these materials and charge injection using electrochemical methods shows that Zr doping also leads to improved electron conductivity and mobility in these nanocrystalline systems. The simple methodology described here to reduce the concentration of interfacial defects may have wider application to improving the efficiency of systems incorporating metal oxide powders and films including photocatalysts, photovoltaics, fuel cells, and related energy applications.
Collapse
Affiliation(s)
| | - Leonardo Lari
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Mark Isaacs
- HarwellXPS, R92 Research Complex at Harwell, Rutherford Appleton Laboratories,
Harwell, Didcot OX11 0QS, UK
- Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - John Carey
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Keith P. McKenna
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Vlado K. Lazarov
- Department
of Physics, University of York, Heslington, York YO10 5DD, UK
| | - Victor Chechik
- Department
of Chemistry, University of York, York YO10 5DD, UK
| | | |
Collapse
|
10
|
Huang Y, Wang C, Wang R, Zhang Y, Li D, Zhu H, Wang G, Zhang X. Ethanol Solution Plasma Loads Carbon Dots onto 2D HNb 3O 8 for Enhanced Photocatalysis. ACS APPLIED MATERIALS & INTERFACES 2023; 15:1157-1166. [PMID: 36541623 DOI: 10.1021/acsami.2c18551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Layered metal oxoacids hold potential as photocatalysts due to their facile exfoliation to two-dimensional (2D) nanosheets with a large surface area and a short migration distance for photoexcited charge carriers. However, the utilization of electrons in photocatalytic processes is restricted by the competitive trapping of electrons by metal ions. In this work, we attempt to improve the utilization of photogenerated electrons over exfoliated HNb3O8 nanosheets by solution plasma activation. On dispersing exfoliated HNb3O8 nanosheets in ethanol solution plasma, the defects in HNb3O8 can be engineered, and carbon dots (CDs) can be anchored on the surface of HNb3O8 nanosheets in situ. In comparison with pristine HNb3O8 nanosheets, the rate of photocatalytic hydrogen evolution can be increased by 317.7 times over the HNb3O8/C heterojunction, and the apparent quantum efficiency of hydrogen production can be as high as 5.05%. The reason for the high photocatalytic performance is explored by the comparison of activation between plasma-in-ethanol and plasma-in-water, which reveals that CD anchoring and defect engineering indeed promote charge separation and hence lead to enhanced photocatalytic activity. This work provides an alternative approach to synthesize CDs and activate 2D-layered compounds with MO6 (M = Nb, Ti, and W) octahedral building blocks in the host layer for enhanced photocatalytic evolution of hydrogen.
Collapse
Affiliation(s)
- Yu Huang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Changhua Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Rui Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Yiyan Zhang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Dashuai Li
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Hancheng Zhu
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Guorui Wang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| | - Xintong Zhang
- Key Laboratory of UV-Emitting Materials and Technology of Chinese Ministry of Education, Northeast Normal University, 5268 Renmin Street, Changchun 130024, China
| |
Collapse
|
11
|
Xue T, Ma L, Lu H, Nie J, Zhu X. The acidochromism of an N-methyl pyrrole-based enone dye toward trifluoroacetic acid in different solvents and solid state. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2022.114051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
12
|
Cardenas L, Molinet-Chinaglia C, Loridant S. Unraveling Ce 3+ detection at the surface of ceria nanopowders by UPS analysis. Phys Chem Chem Phys 2022; 24:22815-22822. [PMID: 36112061 DOI: 10.1039/d2cp02736d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sequential analysis using Ultra-violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS) on ceria nanopowders has been implemented to identify the influence of the X-ray beam on the surface of this oxide. For the first time, UPS analysis evidenced the photoreductive effect of XPS analysis on ceria after an oxidative in situ pretreatment, leading to an overestimation of the Ce3+/Ce4+ ratio obtained by XPS. Based on this spectroscopy methodology, UPS imposes itself as a leading technique for analyzing powders with minimal impact on the authentic chemical state, thus paving the way for identifying the real ratio of Ce4+ and Ce3+ of ceria after oxidative and reductive in situ treatments.
Collapse
Affiliation(s)
- Luis Cardenas
- Univ Lyon, Université Claude Bernard-Lyon 1, CNRS, IRCELYON-UMR 5256, 2 av. A. Einstein, F-69626 Villeurbanne Cedex, France.
| | - Clément Molinet-Chinaglia
- Univ Lyon, Université Claude Bernard-Lyon 1, CNRS, IRCELYON-UMR 5256, 2 av. A. Einstein, F-69626 Villeurbanne Cedex, France.
| | - Stéphane Loridant
- Univ Lyon, Université Claude Bernard-Lyon 1, CNRS, IRCELYON-UMR 5256, 2 av. A. Einstein, F-69626 Villeurbanne Cedex, France.
| |
Collapse
|
13
|
Synthesis of Zinc-Titanium Oxide Nanocomposites by Plasma Jet and Its Application to Photocatalyst. Catalysts 2022. [DOI: 10.3390/catal12091020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In order to synthesize the zinc-titanium (Zn-Ti) oxide nanocomposites using an atmospheric soft plasma jet, in this study mixtures of Zn and Ti precursors such as zinc nitrate and titanium butoxide were first prepared with different molar ratios; the mixed precursors then stirred at 700 rpm for two hours with atmospheric plasma, while maintaining a temperature of 25 °C. All the synthesized Zn-Ti oxide nanocomposites were post-heat-treated at 600 °C for six hours in an electrical furnace. The morphology, particle shape and size, crystal structure, oxidation state, and composition ratio were analyzed using FE-SEM, XRD, SEM-EDS, and Raman spectroscopy. BET was measured to calculate the specific surface area of the Zn-Ti oxide nanocomposites. Photocatalytic activity tests were performed for an application study, with 10 mL of 10 ppm methylene blue dye. UV-visible spectroscopy was performed on five different samples in order to analyze the changes of photocatalytic reactions. When the composition ratio of Zn/Ti was 2/1, maximum photocatalytic efficiency was obtained. We also carried out a theoretical kinetic study.
Collapse
|
14
|
Enhanced Photoelectrochemical Activity of TiO2 Nanotubes Decorated with Lanthanide Ions for Hydrogen Production. Catalysts 2022. [DOI: 10.3390/catal12080866] [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
Highly ordered TiO2 nanotubes (TNTs) decorated with a series of lanthanide ions (Ln3+ = Ho3+, Tb3+, Eu3+, Yb3+, and Er3+) were prepared through an electrochemical process and anodization. The composition, structure, and chemical bond of the as-prepared photocatalysts were characterized through scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and ultraviolet diffuse reflectance spectroscopy. Furthermore, the electrochemical characteristics of the catalysts were analyzed and photoelectrochemical properties were investigated through water splitting. All samples were prepared in the anatase phase without changing the crystal structure. The holmium-doped TNT photocatalyst exhibited the best performance with a hydrogen evolution rate of 90.13 μmol cm−2h−1 and photoconversion efficiency of 2.68% (0 V vs. RHE). Photocatalytic efficiency increased because of the expansion of the absorption wavelength range attributed to the appropriate positioning of the band structure and reduced electron/hole pair recombination resulting from the unhindered electron movement. This study demonstrated the preparation of high-potential solar-active photocatalysts through the synergetic effects of the work function, band edge, and bandgap changes caused by the series of lanthanide combinations with TNTs.
Collapse
|
15
|
Leemans J, Pejović V, Georgitzikis E, Minjauw M, Siddik AB, Deng Y, Kuang Y, Roelkens G, Detavernier C, Lieberman I, Malinowski PE, Cheyns D, Hens Z. Colloidal III-V Quantum Dot Photodiodes for Short-Wave Infrared Photodetection. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2200844. [PMID: 35398996 PMCID: PMC9189642 DOI: 10.1002/advs.202200844] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Short-wave infrared (SWIR) image sensors based on colloidal quantum dots (QDs) are characterized by low cost, small pixel pitch, and spectral tunability. Adoption of QD-SWIR imagers is, however, hampered by a reliance on restricted elements such as Pb and Hg. Here, QD photodiodes, the central element of a QD image sensor, made from non-restricted In(As,P) QDs that operate at wavelengths up to 1400 nm are demonstrated. Three different In(As,P) QD batches that are made using a scalable, one-size-one-batch reaction and feature a band-edge absorption at 1140, 1270, and 1400 nm are implemented. These QDs are post-processed to obtain In(As,P) nanocolloids stabilized by short-chain ligands, from which semiconducting films of n-In(As,P) are formed through spincoating. For all three sizes, sandwiching such films between p-NiO as the hole transport layer and Nb:TiO2 as the electron transport layer yields In(As,P) QD photodiodes that exhibit best internal quantum efficiencies at the QD band gap of 46±5% and are sensitive for SWIR light up to 1400 nm.
Collapse
Affiliation(s)
- Jari Leemans
- Physics and Chemistry of NanostructuresGhent UniversityKrijgslaan 281‐S3Gent9000Belgium
| | | | | | - Matthias Minjauw
- Department of Solid State ScienceGhent UniversityKrijgslaan 281‐S1Gent9000Belgium
| | | | - Yu‐Hao Deng
- Physics and Chemistry of NanostructuresGhent UniversityKrijgslaan 281‐S3Gent9000Belgium
| | | | - Gunther Roelkens
- Photonics Research GroupGhent UniversityTechnologiepark‐Zwijnaarde 126Gent9052Belgium
| | | | | | | | | | - Zeger Hens
- Physics and Chemistry of NanostructuresGhent UniversityKrijgslaan 281‐S3Gent9000Belgium
| |
Collapse
|
16
|
Hashimoto Y, Suzuki H, Kondo T, Abe R, Tamiaki H. Visible-light-induced hydrogen evolution from water on hybrid photocatalysts consisting of synthetic chlorophyll-a derivatives with a carboxy group in the 20-substituent adsorbed on semiconductors. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
17
|
Espinoza EM, Clark JA, Billones MK, Silva GTDM, da Silva CP, Quina FH, Vullev VI. Photophysics and Electrochemistry of Biomimetic Pyranoflavyliums: What Can Bioinspiration from Red Wines Offer? PHOTOCHEM 2022; 2:9-31. [PMID: 35075451 PMCID: PMC8783599 DOI: 10.3390/photochem2010003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Natural dyes and pigments offer incomparable diversity of structures and functionalities, making them an excellent source of inspiration for the design and development of synthetic chromophores with a myriad of emerging properties. Formed during maturation of red wines, pyranoanthocyanins are electron-deficient cationic pyranoflavylium dyes with broad absorption in the visible spectral region and pronounced chemical and photostability. Herein, we survey the optical and electrochemical properties of synthetic pyranoflavylium dyes functionalized with different electron-donating and electron-withdrawing groups, which vary their reduction potentials over a range of about 400 mV. Despite their highly electron-deficient cores, the exploration of pyranoflavyliums as photosensitizers has been limited to the "classical" n-type dye-sensitized solar cells (DSSCs) where they act as electron donors. In light of their electrochemical and spectroscopic properties, however, these biomimetic synthetic dyes should prove to be immensely beneficial as chromophores in p-type DSSCs, where their ability to act as photooxidants, along with their pronounced photostability, can benefit key advances in solar-energy science and engineering.
Collapse
Affiliation(s)
| | - John Anthony Clark
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
| | | | | | - Cassio Pacheco da Silva
- Instituto de Química, Universidade de São Paulo, Avenida Lineu Prestes 748, Cidade Universitaŕia, São Paulo 05508-900, Brazil
| | - Frank Herbert Quina
- Instituto de Química, Universidade de São Paulo, Avenida Lineu Prestes 748, Cidade Universitaŕia, São Paulo 05508-900, Brazil
| | - Valentine Ivanov Vullev
- Department of Chemistry, University of California, Riverside, CA 92521, USA
- Department of Bioengineering, University of California, Riverside, CA 92521, USA
- Department of Biochemistry, University of California, Riverside, CA 92521, USA
- Materials Science and Engineering Program, University of California, Riverside, CA 92521, USA
| |
Collapse
|
18
|
Zhou X, Zhang J, Bai G, Wang C, He W, Sun X, Zhang J, Miao J. A novel energy level detector for molecular semiconductors. Phys Chem Chem Phys 2022; 24:2717-2728. [PMID: 35072681 DOI: 10.1039/d1cp01842f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The multifunction of molecule-based devices is always achieved by improving their charge transport characteristics. These characteristics depend strongly on the energy levels of molecular semiconductors, which fundamentally govern the working principle and device performance. Therefore, an accurate measurement of these energy levels is crucial for evaluating the availability of the prepared materials and thus optimizing the device performance. Here, an easy-to-operate three-terminal hot electron transistor has been developed, which comprises a molecular optoelectronic device that records the charge transport. It achieves exceptional properties including the lowest unoccupied molecular orbit level, highest occupied molecular orbit level, higher energy states, and higher electronic bandgap. When compared with existing techniques such as cyclic voltammetry, inverse photoemission spectroscopy, and ultraviolet photoemission spectroscopy, the hot electron transistor provides in-situ characterization and categorizes the measured energy information as intrinsic properties of the molecular semiconductor. Furthermore, we provide an in-depth understanding of the fundamental device-physics, which provides promising guidance for performance optimization.
Collapse
Affiliation(s)
- Xuehua Zhou
- Anhui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, Key Laboratory of Functional Coordination Compounds of Anhui Higher Education Institutes, Anqing Normal University, Anqing 246011, P. R. China.
| | - Juansu Zhang
- Anhui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, Key Laboratory of Functional Coordination Compounds of Anhui Higher Education Institutes, Anqing Normal University, Anqing 246011, P. R. China.
| | - Guoliang Bai
- Anhui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, Key Laboratory of Functional Coordination Compounds of Anhui Higher Education Institutes, Anqing Normal University, Anqing 246011, P. R. China.
| | - Chunhua Wang
- Anhui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, Key Laboratory of Functional Coordination Compounds of Anhui Higher Education Institutes, Anqing Normal University, Anqing 246011, P. R. China.
| | - Wenxiang He
- Anhui Province Key Laboratory of Optoelectronic and Magnetism Functional Materials, Key Laboratory of Functional Coordination Compounds of Anhui Higher Education Institutes, Anqing Normal University, Anqing 246011, P. R. China.
| | - Xiangnan Sun
- Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, P. R. China
| | - Jianli Zhang
- State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering, P. R. China
| | - Jiaojiao Miao
- School of Life Sciences, Northwestern Polytechnical University, Xi'an, Shanxi 710072, P. R. China
| |
Collapse
|
19
|
Mikrut P, Święs A, Kobielusz M, Chmielarz L, Macyk W. Selective and efficient catalytic and photocatalytic oxidation of diphenyl sulphide to sulfoxide and sulfone: the role of hydrogen peroxide and TiO 2 polymorph. RSC Adv 2022; 12:1862-1870. [PMID: 35425200 PMCID: PMC8979124 DOI: 10.1039/d1ra08364c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/24/2021] [Indexed: 01/08/2023] Open
Abstract
In this paper, we describe the role of anatase and rutile crystal phases on diphenyl sulphide (Ph2S) catalytic and photocatalytic oxidation. The highly selective and efficient synthesis of diphenyl sulfoxide (Ph2SO) and diphenyl sulfone (Ph2SO2) at titanium dioxide was demonstrated. Ph2S oxidation in the presence of hydrogen peroxide at anatase-TiO2 can take place both as a catalytic and photocatalytic reaction, while at rutile-TiO2 only photocatalytic oxidation is possible. The reaction at anatase leads mainly to Ph2SO2, whereas, in the presence of rutile a complete conversion to Ph2SO is achieved after only 15 min (nearly 100% selectivity). Studies on the mechanistic details revealed a dual role of H2O2. It acts as a substrate in the reaction catalysed only by anatase, but it also plays a key role in alternative photocatalytic oxidation pathways. The presented study shows the applicability of photocatalysis in efficient and selective sulfoxide and sulfone production. Selective sulfoxide and sulfone production can be precisely controlled by choosing TiO2 polymorph and the reaction mode (catalysis versus photocatalysis).![]()
Collapse
Affiliation(s)
- Paweł Mikrut
- Faculty of Chemistry, Jagiellonian University ul. Gronostajowa 2 30-387 Kraków Poland
| | - Aneta Święs
- 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
| | - Lucjan Chmielarz
- 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
| |
Collapse
|
20
|
Fernández-Catalá J, Navlani-García M, Berenguer-Murcia Á, Cazorla-Amorós D. Exploring CuxO-doped TiO2 modified with carbon nanotubes for CO2 photoreduction in a 2D-flow reactor. J CO2 UTIL 2021. [DOI: 10.1016/j.jcou.2021.101796] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Influence of the calcination of TiO2-reduced graphite hybrid for the photocatalytic reduction of carbon dioxide. Catal Today 2021. [DOI: 10.1016/j.cattod.2021.05.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
23
|
Bui DP, Pham MT, Tran HH, Nguyen TD, Cao TM, Pham VV. Revisiting the Key Optical and Electrical Characteristics in Reporting the Photocatalysis of Semiconductors. ACS OMEGA 2021; 6:27379-27386. [PMID: 34693158 PMCID: PMC8529670 DOI: 10.1021/acsomega.1c04215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
Photocatalysis has been studied and considered as a green and practical approach in addressing environmental pollution. However, factors that affect photocatalytic performance have not been systematically studied. In this work, we have presented a comprehensive roadmap for characterizing, interpreting, and reporting semiconductors' electrical and optical properties through routinely used techniques such as diffuse reflectance spectroscopy, electrochemical techniques (Mott-Schottky plots), photoluminescence, X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy in the context of photocatalysis. Having precisely studied the band structure of three representative photocatalysts, we have presented and highlighted the essential information and details, which are critical and beneficial for studies of (1) band alignments, (2) redox potentials, and (3) defects. Further works with a comprehensive understanding of the band structure are desirable and hold great promise.
Collapse
Affiliation(s)
- Dai-Phat Bui
- Photocatalysis
Research Group (PRG), Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, District
5, Ho Chi Minh City 700000, Vietnam
- Vietnam
National University—Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Faculty
of Materials Science and Technology, University
of Science, VNU-HCM, 227 Nguyen Van Cu Street, District 5, Ho Chi
Minh City 700000, Vietnam
| | - Minh-Thuan Pham
- Photocatalysis
Research Group (PRG), Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, District
5, Ho Chi Minh City 700000, Vietnam
- Vietnam
National University—Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Faculty
of Materials Science and Technology, University
of Science, VNU-HCM, 227 Nguyen Van Cu Street, District 5, Ho Chi
Minh City 700000, Vietnam
| | - Hong-Huy Tran
- Photocatalysis
Research Group (PRG), Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, District
5, Ho Chi Minh City 700000, Vietnam
- Vietnam
National University—Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Faculty
of Materials Science and Technology, University
of Science, VNU-HCM, 227 Nguyen Van Cu Street, District 5, Ho Chi
Minh City 700000, Vietnam
| | - Thanh-Dat Nguyen
- Photocatalysis
Research Group (PRG), Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, District
5, Ho Chi Minh City 700000, Vietnam
- Vietnam
National University—Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Faculty
of Materials Science and Technology, University
of Science, VNU-HCM, 227 Nguyen Van Cu Street, District 5, Ho Chi
Minh City 700000, Vietnam
| | - Thi Minh Cao
- Ho
Chi Minh City University of Technology (HUTECH), 475A Dien Bien Phu Street, Binh
Thanh District, Ho Chi Minh City 700000, Vietnam
| | - Viet Van Pham
- Photocatalysis
Research Group (PRG), Faculty of Materials Science and Technology, University of Science, VNU-HCM, 227 Nguyen Van Cu Street, District
5, Ho Chi Minh City 700000, Vietnam
- Vietnam
National University—Ho Chi Minh City, Linh Trung Ward, Thu Duc District, Ho Chi Minh City 700000, Vietnam
- Faculty
of Materials Science and Technology, University
of Science, VNU-HCM, 227 Nguyen Van Cu Street, District 5, Ho Chi
Minh City 700000, Vietnam
| |
Collapse
|
24
|
Jenkins T, Alarco JA, Cowie B, Mackinnon IDR. Validating the Electronic Structure of Vanadium Phosphate Cathode Materials. ACS APPLIED MATERIALS & INTERFACES 2021; 13:45505-45520. [PMID: 34544241 DOI: 10.1021/acsami.1c12447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Investigation of the electronic structure of contending battery electrode materials is an essential step for developing a detailed mechanistic understanding of charge-discharge properties. Herein, we use synchrotron soft X-ray absorption spectroscopy (XAS) in combination with complementary experiments and density functional theory calculations to map the electronic structure, band positioning, and band gap of prototype vanadium(III) phosphate cathode materials, Na3V2(PO4)3, Li3V2(PO4)3, and K3V3(PO4)4·H2O, for alkali-ion rechargeable batteries. XAS fluorescence yield and electron yield measurements reveal substantial variation in surface-to-bulk atomic structure, vanadium oxidation states, and density of oxygen hole states across all samples. We attribute this variation to an intrinsic alkali metal surface depletion identified across these alkali metal vanadium(III) phosphates. We propose that an alkali-depleted surface provides a beneficial interface with the bulk structure(s) that raises the Fermi level and improves surface charge transfer kinetics. Furthermore, we discuss how this effect can play a significant role in reducing the electronic and ionic diffusion limitations of alkali vanadium phosphates in alkali-ion rechargeable batteries. These findings clarify the electronic structure and properties of alkali metal vanadium phosphates and offer guidance on future strategies to improve vanadium phosphate battery performance.
Collapse
Affiliation(s)
| | | | - Bruce Cowie
- Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
| | | |
Collapse
|
25
|
Samokhvalov A. Understanding the structure, bonding and reactions of nanocrystalline semiconductors: a novel high-resolution instrumental method of solid-state synchronous luminescence spectroscopy. Phys Chem Chem Phys 2021; 23:7022-7036. [PMID: 33876074 DOI: 10.1039/d0cp06709a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This Perspective Article describes the recent advancements in studies of nanocrystalline metal oxides using a novel ultra-high resolution method, solid-state synchronous luminescence spectroscopy (SS-SLS). Semiconductors notably include titanium dioxide and these studies shed light on the detailed electronic structure, composition, and their reactions. First, we critically discuss the limitations of the major existing non-spectroscopic and spectroscopic methods of characterization of electronic structure of nanocrystalline semiconductors and insulators. Second, we describe the foundations and the setup of SS-SLS as an enhanced-resolution, facile, non-contact, non-destructive, and highly capable method of studies of nanomaterials. Third, the following insights are featured which are obtained by SS-SLS, but are not available by other methods: (a) detection of traps of electric charge (specific mid-gap states); (b) discrimination between "surface" and "bulk" sites; (c) in situ studies of composite nanomaterials and mechanisms of reactions, (d) the derivative SS-SLS for accurate determination of energies of absorption and emission. The specific advantages of SS-SLS versus other methods and in direct comparison with "conventional" photoluminescence spectroscopy are highlighted. Finally, new opportunities and challenges of SS-SLS are presented. SS-SLS is an advanced spectroscopic method with significant potential to aid academia and industry in studies of chemo-sensing, photocatalysis, optoelectronic materials, applied surface science, development of instrumental analysis, and studies of mechanisms of surface and "bulk" chemical reactions.
Collapse
Affiliation(s)
- Alexander Samokhvalov
- Department of Chemistry, Morgan State University, 1700 East Cold Spring Lane, Baltimore, MD 21251, USA.
| |
Collapse
|
26
|
Maver K, Arčon I, Fanetti M, Emin S, Valant M, Lavrenčič Štangar U. Improved photocatalytic activity of anatase-rutile nanocomposites induced by low-temperature sol-gel Sn-modification of TiO2. Catal Today 2021. [DOI: 10.1016/j.cattod.2020.01.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
27
|
Verma P, Wanchoo RK, Toor AP. A green and energy-efficient photocatalytic process for the accelerated synthesis of lactic acid esters using functionalized quantum dots. REACT CHEM ENG 2021. [DOI: 10.1039/d1re00017a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Sulphonated-grafted-titania quantum dot catalyzed green and energy-efficient photochemical process for the synthesis of valuable lactic acid esters at ambient temperature.
Collapse
Affiliation(s)
- Priyanka Verma
- Dr. SSB University Institute of Chemical Engineering and Technology
- Panjab University
- Chandigarh
- India
| | - Ravinder Kumar Wanchoo
- Dr. SSB University Institute of Chemical Engineering and Technology
- Panjab University
- Chandigarh
- India
| | - Amrit Pal Toor
- Dr. SSB University Institute of Chemical Engineering and Technology
- Panjab University
- Chandigarh
- India
- Energy Research Centre
| |
Collapse
|
28
|
Jo C, Lee S, Kim J, Heo JS, Kang DW, Park SK. Enhanced Electro-Optical Performance of Inorganic Perovskite/a-InGaZnO Phototransistors Enabled by Sn-Pb Binary Incorporation with a Selective Photonic Deactivation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:58038-58048. [PMID: 33332112 DOI: 10.1021/acsami.0c17862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Optoelectronic applications using perovskites have emerged as one of the most promising platforms such as phototransistors, photovoltaics, and photodetectors. However, high-performance and reliable perovskite photonic devices are often hindered by the limited spectral ranges of the perovskite system along with the lack of appropriate processing technologies for the implementation of reliable device architectures. Here, we explore a hybrid phototransistor with a heterojunction of a Sn-Pb binary mixed halide perovskite (CsSn0.6Pb0.4I2.6Br0.4) light absorber and an amorphous-In-Ga-Zn-O (a-IGZO) charge carrying layer. By incorporating Sn-Pb binary components with an all-inorganic base, broadening of light-absorbing spectral ranges with enhanced stability has been achieved, indicating inevitable highly increased conductivity, which triggers a high off-current of the devices. Accordingly, the selectively ultraviolet (UV)-irradiated electrical deactivation (SUED) process is carried out to suppress the high off-current with a reliable device structure. Particularly, it is noted that the selective UV irradiation can facilitate oxidation and distortion of the chemical structure in specific perovskite regions, providing enhanced gate bias modulation of the phototransistor with an increased on/off-current ratio from ∼103 to ∼106. Finally, the SUED-processed phototransistor exhibits an improvement in the photosensitivity by more than 3 orders of magnitude up to 8.0 × 104 and detects in the spectral range from visible to near-infrared (NIR) light (∼860 nm) with good on/off switching behaviors.
Collapse
Affiliation(s)
- Chanho Jo
- Department of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Seojun Lee
- School of Energy Systems Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jaehyun Kim
- Department of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jae Sang Heo
- Department of Medicine, University of Connecticut School of Medicine, Farmington, Connecticut 06030, United States
| | - Dong-Won Kang
- School of Energy Systems Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sung Kyu Park
- Department of Electrical and Electronics Engineering, Chung-Ang University, Seoul 06974, Republic of Korea
| |
Collapse
|
29
|
Sun J, Sun J, Wang X. Anatase TiO
2
with Co‐exposed (001) and (101) Surface‐Based Photocatalytic Materials for Energy Conversion and Environmental Purification. Chem Asian J 2020; 15:4168-4183. [DOI: 10.1002/asia.202001085] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/28/2020] [Indexed: 01/15/2023]
Affiliation(s)
- Jingjing Sun
- School of Environmental Science and Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 P. R. China
| | - Jing Sun
- School of Environmental Science and Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 P. R. China
| | - Xikui Wang
- School of Environmental Science and Engineering Qilu University of Technology (Shandong Academy of Sciences) Jinan 250353 P. R. China
- Shandong Agriculture and Engineering University Ji'nan 250100 P. R. China
| |
Collapse
|
30
|
Unravelling the Mechanisms that Drive the Performance of Photocatalytic Hydrogen Production. Catalysts 2020. [DOI: 10.3390/catal10080901] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The increasing interest and applications of photocatalysis, namely hydrogen production, artificial photosynthesis, and water remediation and disinfection, still face several drawbacks that prevent this technology from being fully implemented at the industrial level. The need to improve the performance of photocatalytic processes and extend their potential working under visible light has boosted the synthesis of new and more efficient semiconductor materials. Thus far, semiconductor–semiconductor heterojunction is the most remarkable alternative. Not only are the characteristics of the new materials relevant to the process performance, but also a deep understanding of the charge transfer mechanisms and the relationship with the process variables and nature of the semiconductors. However, there are several different charge transfer mechanisms responsible for the activity of the composites regardless the synthesis materials. In fact, different mechanisms can be carried out for the same junction. Focusing primarily on the photocatalytic generation of hydrogen, the objective of this review is to unravel the charge transfer mechanisms after the in-depth analyses of already reported literature and establish the guidelines for future research.
Collapse
|
31
|
Degenerated TiO
2
Semiconductor Modified with Ni and Zn as Efficient Photocatalysts for the Water Splitting Reaction. ChemCatChem 2020. [DOI: 10.1002/cctc.202000691] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
32
|
Enhanced Photocatalytic Properties of PET Filaments Coated with Ag-N Co-Doped TiO 2 Nanoparticles Sensitized with Disperse Blue Dyes. NANOMATERIALS 2020; 10:nano10050987. [PMID: 32455664 PMCID: PMC7279539 DOI: 10.3390/nano10050987] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 11/30/2022]
Abstract
In this study, the effects of disperse blue dye-sensitization on the photocatalytic properties of the Ag-N co-doped TiO2 nanoparticles loaded on polyethylene terephthalate (PET) filaments are investigated under visible light irradiation. The microstructure and photocatalytic properties of the as-synthesized TiO2 nanocomposites, as well as the as-prepared PET filaments, are systematically characterized. The photocatalytic performance of the PET filaments coated with the Ag-N co-doped TiO2 nanoparticles sensitized with disperse blue dyes is evaluated via its capacity of photo-degrading methyl orange (MO) dyes under visible light irradiation. It is found that the holes are the predominant reactive radical species and the hydroxyl and superoxide radicals play a subordinate role in the photocatalytic reaction process. The reaction rate constant of the photocatalytic composite filaments is nearly 4.0 times higher than that of the PET filaments loaded solely with TiO2 nanoparticles. The resultant photocatalytic composite filaments are evident to be capable of repeatedly photo-degrading MO dyes without losing its photocatalytic activity significantly.
Collapse
|
33
|
Photocatalytic Activities of PET Filaments Deposited with N-Doped TiO2 Nanoparticles Sensitized with Disperse Blue Dyes. Catalysts 2020. [DOI: 10.3390/catal10050531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
In this study, the enhanced photocatalytic activities of polyethylene terephthalate (PET) filaments deposited with N-doped Titanium dioxide (TiO2) nanoparticles sensitized with water insoluble disperse blue SE–2R dye were investigated. The PET filaments were loaded with two types of N-doped TiO2 nanoparticles, one with and the other without being sensitized with disperse blue SE–2R dye, in one-pot hydrothermal process respectively. The differences in photocatalytic activities between the N-doped TiO2 and the dye-sensitized N-doped TiO2 nanoparticles when exposed to both UV rays and visible lights were analyzed and compared by using their photodegradations of methylene blue (MB) dye. It was demonstrated that the disperse blue dye facilitated the electron–hole separation in N-doped TiO2 nanoparticles faster under UV irradiation than that under visible light irradiation. The enhanced photocatalytic activity of the PET filaments loaded with dye-sensitized N-doped TiO2 nanoparticles exposure to UV irradiation, in comparison with that under visible light irradiation, was attributed to both improved light absorption capacity and high separation efficiency of photo-generated electron–hole pairs. Furthermore, the conduction band and band gap of the PET filaments deposited with N-doped TiO2 nanoparticles sensitized with disperse blue SE–2R dye were influenced by the wavelength of light sources, while its valence band was not affected. The PET filaments deposited with dye-sensitized N-doped TiO2 nanoparticles have a potential application to degrade organic pollutants.
Collapse
|
34
|
Nosaka Y, Nosaka AY. Intrinsic nature of photocatalysis by comparing with electrochemistry. Phys Chem Chem Phys 2020; 22:7146-7154. [PMID: 32219246 DOI: 10.1039/d0cp00771d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photocatalysis has been gathering much attention because of the unique applications of photoenergy for environmental cleaning and solar fuel production. Electron transfer (ET) at the solid-liquid interface, which initiates photocatalytic reactions, has been the subject of electrochemistry, and hence the reactions are often analyzed in terms of electrochemistry. However, how extensively the concept of electrochemistry can be incorporated has not been discussed so far. In this report, by comparing with electrochemistry, the intrinsic nature of photocatalysis is disclosed and the limitation of the use of the concept of electrochemistry was pointed out. The electric potential near the photocatalyst surface was calculated and visualized, showing a potential gradient similar to that at the electrode surface but localized near the positive hole. Since the frequency of the ET at the photocatalyst surface is limited by the photon absorption, the investigation of photocatalysis in terms of energy states and kinetics should be different from those for electrochemistry. Since semiconductor photocatalysts are not wired to the electric source, the estimation of energy band positions may be altered, which was actually discussed in terms of the band alignments of anatase and rutile TiO2 crystals.
Collapse
Affiliation(s)
- Yoshio Nosaka
- Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka, 940-2188, Japan.
| | - Atsuko Y Nosaka
- Department of Materials Science and Technology, Nagaoka University of Technology, Nagaoka, 940-2188, Japan.
| |
Collapse
|
35
|
Kang Y, Kim K, Cho B, Kwak Y, Kim J. Highly Sensitive Detection of Benzene, Toluene, and Xylene Based on CoPP-Functionalized TiO 2 Nanoparticles with Low Power Consumption. ACS Sens 2020; 5:754-763. [PMID: 32048833 DOI: 10.1021/acssensors.9b02310] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Among various metal oxides, titanium dioxide (TiO2) has received considerable interest as a gas-sensing material owing to its high reliability at high operating temperatures. Nonetheless, TiO2 generally has low sensitivity to target gases. In particular, TiO2-based sensors have difficulty in sensitively detecting benzene, toluene, and xylene (referred to as BTX). Moreover, the reported TiO2-based sensors have not simultaneously satisfied the demand for tens of ppb BTX detection and operation with low power consumption. This work proposes a BTX sensor using cobalt porphyrin (CoPP)-functionalized TiO2 nanoparticles as a sensing material on a suspended microheater fabricated by bulk micromachining for low power consumption. TiO2 nanoparticles show an enhanced sensitivity (245%) to 10 ppm toluene with CoPP functionalization. The proposed sensor exhibits high sensitivity to BTX at concentrations ranging from 10 ppm down to several ppb. The high reliability of the sensor is also explored through the long-time operation with repeated exposure to 10 ppm toluene for 14 h.
Collapse
Affiliation(s)
- Yunsung Kang
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Kwanhun Kim
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Byeonghwa Cho
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Yeunjun Kwak
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| | - Jongbaeg Kim
- School of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea
| |
Collapse
|
36
|
Zhou BX, Ding SS, Wang Y, Wang XR, Huang WQ, Li K, Huang GF. Type-II/type-II band alignment to boost spatial charge separation: a case study of g-C 3N 4 quantum dots/a-TiO 2/r-TiO 2 for highly efficient photocatalytic hydrogen and oxygen evolution. NANOSCALE 2020; 12:6037-6046. [PMID: 32129406 DOI: 10.1039/d0nr00176g] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Efficient spatial charge separation and transfer that are critical factors for solar energy conversion primarily depend on the energetic alignment of the band edges at interfaces in heterojunctions. Herein, we first report that constructing a 0D/0D type-II(T-II)/T-II heterojunction is an effective strategy to ingeniously achieve long-range charge separation by taking a ternary heterojunction of TiO2 and graphitic carbon nitride (g-C3N4) as a proof-of-concept. Incorporating g-C3N4 quantum dots (QCN), as the third component, into the commercial P25 composed of anatase (a-TiO2) and rutile (r-TiO2) can be realized via simply mixing the commercially available Degussa P25 and QCN solution followed by heat treatment. The strong coupling and matching band structures among a-TiO2, r-TiO2 and QCN result in the construction of novel T-II/T-II heterojunctions, which would promote the spatial separation and transfer of photogenerated electrons and holes. Moreover, QCN plays a key role in reinforcing light absorption. Particularly, the unique 0D/0D architecture possesses the advantages of abundant active sites for the photocatalytic reaction. As a result, the optimized QCN/a-TiO2/r-TiO2 heterojunctions exhibit enhanced photocatalytic H2 and O2 evolution, especially the hydrogen evolution rate (49.3 μmol h-1) is 11.7 times that of bare P25 under visible light irradiation, and sufficient catalytic stability as evidenced by the recycling experiments. The remarkably enhanced photocatalytic activity can be attributed to the synergistic effects of the energy level alignment at interfaces, the dimensionality and component of the heterojunctions. This work provides a stepping stone towards the design of novel heterojunctions for photocatalytic water splitting.
Collapse
Affiliation(s)
- Bing-Xin Zhou
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Shuang-Shuang Ding
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Yan Wang
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Xiao-Rui Wang
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Wei-Qing Huang
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| | - Kai Li
- State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China
| | - Gui-Fang Huang
- Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082, China.
| |
Collapse
|
37
|
Díaz de León JN, Rodríguez JR, Rojas J, Esqueda-Barrón Y, Cardenas L, Ramesh Kumar C, Alonso-Nuñez G, Fuentes-Moyado S. New Insight on the Formation of Sodium Titanates 1D Nanostructures and Its Application on CO 2 Hydrogenation. Front Chem 2019; 7:750. [PMID: 31781539 PMCID: PMC6856218 DOI: 10.3389/fchem.2019.00750] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/21/2019] [Indexed: 11/13/2022] Open
Abstract
The aim of this work is focused on the study of a series of non-traditional catalytic nanomaterials to transform greenhouse CO2 gas into added-value products. We found encouraging results of CO2 hydrogenation activity over sodium titanates with different morphologies. The yield to methanol increases with the increase in the Na incorporated in the nanostructures confirming the proposed mechanism. Samples were prepared at different times of hydrothermal treatment (HTT) with NaOH solutions, and these materials were labeled as Ti-nR-x with x as the hours on the HTT. HRTEM initially showed sphere-shaped nanoparticles in the TiO2 commercial nanopowder, increasing the HTT resulted in morphological changes in which the structures passed from nanosheets and finally to nanorods after 30 h. The X-ray diffraction and Raman spectroscopy results indicated the formation of sodium titanates such as Na2Ti3O7 with short Ti-O bonds and that Na begins to be incorporated into the distorted TiO6 crystalline structure after 5 h of HTT (until 12 wt%). The crystalline and shape transformation resulted in a significant modification on the textural properties passing from 51 m2.g−1 to 150 m2.g−1 and from a pore volume of 0.12 cm3.g−1 to 1.03 cm3.g−1 for Ti-ref and Ti-nR-30 respectively. We also observed differences in the electronic properties as the bandgap presented a blue shift from 3.16 eV on the TiO2 reference nano-powder to 3.44 eV for the Ti-nR-30 calcined sample. This fact coincides with the presence of a more electron-rich state of the Ti4+ and the formation of negative charge layer induced by the presence of Na+ interlayer cations detected by XPS analysis, at the same this helped us to explain the catalytic activity results.
Collapse
Affiliation(s)
- J Noé Díaz de León
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Jassiel R Rodríguez
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Joel Rojas
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Yasmin Esqueda-Barrón
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Luis Cardenas
- Institut de Recherches sur la Catalyse et l'Environnement de Lyon - IRCELYON - UMR 5256, CNRS-UCB Lyon 1, Université de Lyon, Lyon, France
| | - Chowdari Ramesh Kumar
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Gabriel Alonso-Nuñez
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| | - Sergio Fuentes-Moyado
- Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, Mexico
| |
Collapse
|
38
|
Jeon JB, Kim BJ, Bang GJ, Kim MC, Lee DG, Lee JM, Lee M, Han HS, Boschloo G, Lee S, Jung HS. Photo-annealed amorphous titanium oxide for perovskite solar cells. NANOSCALE 2019; 11:19488-19496. [PMID: 31552996 DOI: 10.1039/c9nr05776e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electron selective layers are important to the efficiency, stability and hysteresis of perovskite solar cells. Photo-annealing is a low-cost, roll-to-roll-compatible process that can be applied to the post-treatment fabrication of sol-gel based metal oxide layers. Here, we fabricate an amorphous titanium oxide electron selective layer at a low temperature in a dry atmosphere using a UV light annealing system and compare it with a thermal annealing process. Active oxygen species are created by using UV light to promote hydrolysis and condense the TiO2 precursor, which removes organic ligands effectively. The photo-annealed TiO2-based perovskite solar cell has a power conversion efficiency of 19.37% without hysteresis.
Collapse
Affiliation(s)
- Jae Bum Jeon
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Byeong Jo Kim
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea. and Department of Chemistry-Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Gi Joo Bang
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Min-Cheol Kim
- Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, USA
| | - Dong Geon Lee
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Jae Myeong Lee
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Minho Lee
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
| | - Hyun Soo Han
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Gerrit Boschloo
- Department of Chemistry-Ångström Laboratory, Physical Chemistry, Uppsala University, Box 523, SE 751 20 Uppsala, Sweden
| | - Sangwook Lee
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
| | - Hyun Suk Jung
- School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| |
Collapse
|
39
|
Zavjalov A, Tikhonov S, Kosyanov D. TiO 2-SrTiO 3 Biphase Nanoceramics as Advanced Thermoelectric Materials. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E2895. [PMID: 31500279 PMCID: PMC6766282 DOI: 10.3390/ma12182895] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/25/2019] [Accepted: 09/03/2019] [Indexed: 12/14/2022]
Abstract
The review embraces a number of research papers concerning the fabrication of oxide thermoelectric systems, with TiO2-SrTiO3 biphase ceramics being emphasized. The ceramics is particularly known for a two-dimensional electron gas (2DEG) forming spontaneously on the TiO2/SrTiO3 heterointerface (modulation doping), unlike ordinary 2DEG occurrence on specially fabricated thin film. Such effect is provided by the SrTiO3 conduction band edge being 0.40 and 0.20 eV higher than that for anatase and rutile TiO2, respectively. That is why, in the case of a checkered arrangement of TiO2 and SrTiO3 grains, the united 2D net is probably formed along the grain boundaries with 2DEG occurring there. To reach such conditions, there should be applied novelties in the field of ceramics materials science, because it is important to obtain highly dense material preserving small (nanoscale) grain size and thin interface boundary. The review also discusses some aspects of reactive spark plasma sintering as a promising method of preparing perovskite-oxide TiO2-SrTiO3 thermoelectric materials for high-temperature applications.
Collapse
Affiliation(s)
- Alexey Zavjalov
- School of Natural Sciences, Far Eastern Federal University, 8 Sukhanova Street, Vladivostok 690950, Russian Federation.
| | - Sergey Tikhonov
- School of Natural Sciences, Far Eastern Federal University, 8 Sukhanova Street, Vladivostok 690950, Russian Federation.
| | - Denis Kosyanov
- School of Natural Sciences, Far Eastern Federal University, 8 Sukhanova Street, Vladivostok 690950, Russian Federation.
| |
Collapse
|
40
|
Impact of the absolute rutile fraction on TiO2 visible-light absorption and visible-light-promoted photocatalytic activity. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2019.111940] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|