Dynamic charge transfer through Fermi level equilibration in the p-CuFe2O4/n-NiAl LDH interface towards photocatalytic application

2020 ◽  
Vol 10 (18) ◽  
pp. 6285-6298 ◽  
Author(s):  
Snehaprava Das ◽  
Sulagna Patnaik ◽  
Kulamani Parida
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Energy Level ◽  
Fermi Level ◽  
Vacuum Energy ◽  
Electron Hole ◽  
Photocatalytic Application ◽  
Dynamic Charge ◽  
Hole Recombination

The Ni Al LDH–CuFe2O4 p–n heterojunction, through vacuum energy level bending, inhibits electron hole recombination and enhances photocatalytic activity.

Enhanced visible-active photocatalytic behaviors observed in Mn-doped BiFeO3

2018 ◽  
Vol 32 (17) ◽  
pp. 1850185 ◽  
Author(s):  
Yun-Hui Si ◽  
Yu Xia ◽  
Ya-Yun Li ◽  
Shao-Ke Shang ◽  
Xin-Bo Xiong ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Diffuse Reflectance Spectroscopy ◽  
X Ray Diffraction ◽  
Electron Hole ◽  
X Ray ◽  
Mn Doped ◽  
Hole Recombination ◽  
Narrow Band Gap Semiconductors

A series of BiFeO3 and BiFe[Formula: see text]Mn[Formula: see text]O3 (x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) were synthesized by a hydrothermal method. The samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy (EDS) and UV–Vis diffuse reflectance spectroscopy, and their photocatalytic activity was studied by photocatalytic degradation of methylene blue in aqueous solution under visible light irradiation. The band gap of BiFeO3 was significantly decreased from 2.26 eV to 1.90 eV with the doping of Mn. Furthermore, the 6% Mn-doped BiFeO3 photocatalyst exhibited the best activity with a degradation rate of 94% after irradiation for 100 min. The enhanced photocatalytic activity with Mn doping could be attributed to the enhanced optical absorption, increment of surface reactive sites and reduction of electron–hole recombination. Our results may be conducive to design more efficient photocatalysts responsive to visible light among narrow band gap semiconductors.

The Effect of Chromium on the Optical Properties and Photoactivity of Nano-Particulate Rutile

2012 ◽  
Vol 554-556 ◽  
pp. 502-506 ◽  
Author(s):  
Li Wei Wang ◽  
Terry A. Egerton
Keyword(s):  
Optical Properties ◽  
Photocatalytic Activity ◽  
Reflectance Spectroscopy ◽  
Electron Trapping ◽  
Electron Hole ◽  
High Chromium ◽  
Chromium Doping ◽  
Chromium Addition ◽  
Co Precipitation ◽  
Hole Recombination

Chromium doped rutile TiO2was synthesized by either co-precipitation or impregnation (surface-doping) and characterized by XRD and reflectance spectroscopy. Chromium addition did not change the TiO2structure nor did the structure of the co-precipitated products differ from that of the impregnated samples. However, chromium doping moved the absorption of both sets of products into the visible and significantly affected the TiO2photocatalytic activity for isopropanol (IPA) oxidation. At high chromium concentrations the photoactivity of the co-precipitated samples was reduced by a larger amount than that of the impregnated samples; this was attributed to a higher concentration of Cr3+ions in the rutile lattice. Unexpectedly, increased photoactivity was measured for low Cr levels of surface-doped rutile. This may be caused by increased electron-trapping, at surface Cr6+ions, and correspondingly reduced, electron-hole recombination.

Unraveling the quantum dynamics origin of high photocatalytic activity in nitrogen-doped anatase TiO2: time-domain ab initio analysis

2020 ◽  
Vol 8 (47) ◽  
pp. 25235-25244
Author(s):  
Yating Yang ◽  
Zhaosheng Zhang ◽  
Wei-Hai Fang ◽  
Sebastian Fernandez-Alberti ◽  
Run Long
Keyword(s):  
Photocatalytic Activity ◽  
Ab Initio ◽  
Time Domain ◽  
Quantum Dynamics ◽  
High Photocatalytic Activity ◽  
Anatase Tio2 ◽  
Electron Hole ◽  
Nitrogen Doped ◽  
Hole Recombination

TiO2 doping with nitrogen greatly suppresses nonradiative electron-hole recombination and enhances photocatalytic activity.

Synthesis of TiO2-Reduced Graphene Oxide Nanocomposites Offering Highly Enhanced Photocatalytic Activity

2019 ◽  
Vol 19 (11) ◽  
pp. 7089-7096 ◽  
Author(s):  
Wufa Li ◽  
Xiaohong Yang ◽  
Haitao Fu ◽  
Xizhong An ◽  
Haiyang Zhao
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Environmental Remediation ◽  
Hydrothermal Reaction ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Reduced Graphene ◽  
Vis Spectroscopy ◽  
Hole Recombination

Photogenerated electron–hole recombination significantly restricts the catalytic efficiency of titanium dioxide (TiO2). Various approaches have been developed to overcome this problem, yet it remains challenging. Recently, graphene modification of TiO2 has been considered as an effective alternative to prevent electron–hole recombination and consequently enhance the photocatalytic performance of TiO2. This study reports an efficient but simple hydrothermal method utilizing titanium (IV) butoxide (TBT) and graphene oxide (GO) to prepare TiO2-reduced graphene oxide (RGO) nanocomposites under mild reaction conditions. This method possesses several advantageous features, including no requirement of high temperature for TiO2 crystallization and a one-step hydrothermal reaction for mild reduction of GO without a reducing agent, which consequently makes the production of TiO2-RGO nanocomposites possible in a green and an efficient synthetic route. Moreover, the as-synthesized nanocomposites were characterized by numerous advanced techniques (SEM, TEM, BET, XRD, XPS, and UV-vis spectroscopy). In particular, the photocatalytic activities of the synthesized TiO2-RGO nanocomposites were evaluated by degrading the organic molecules (methylene blue, MB), and it was found that the photocatalytic activity of TiO2-RGO nanocomposites is ~4.5 times higher compared to that of pure TiO2. These findings would be useful for designing reduced graphene oxide-metal oxide hybrids with desirable functionalities in various applications for energy storage devices and environmental remediation.

scholarly journals Photoelectrochemical and theoretical investigation of the photocatalytic activity of TiO2 : N

RSC Advances ◽  
2016 ◽  
Vol 6 (92) ◽  
pp. 89687-89698 ◽  
Author(s):  
Gabriela Byzynski Soares ◽  
Renan Augusto Pontes Ribeiro ◽  
Sergio Ricardo de Lazaro ◽  
Caue Ribeiro
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Effective Mass ◽  
Theoretical Investigation ◽  
Hole Pair ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
N Doping ◽  
Hole Recombination

In N-doping on TiO2 nanomaterial occurs a big decrease of band-gap (1 eV); however, its photocatalysis is low. We clarify such fact from effective mass, i.e., the electron–hole recombination is more than creation of electron–hole pair.

Modulating the atomic and electronic structures through alloying and heterostructure of single-layer MoS2

2014 ◽  
Vol 2 (7) ◽  
pp. 2101-2109 ◽  
Author(s):  
Xiao-Lin Wei ◽  
Hui Zhang ◽  
Gen-Cai Guo ◽  
Xi-Bo Li ◽  
Woon-Ming Lau ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Density ◽  
Electronic Structures ◽  
Single Layer ◽  
Electron Hole ◽  
Hole Recombination ◽  
Spontaneous Separation

Charge density of the VBM (green) and CBM (blue) for armchair MoS2–WS2 heterostructures, indicating the spontaneous separation of photo-generated electrons and holes, which could strongly enhance the photocatalytic activity due to suppression of the electron–hole recombination.

Photocatalytic activity of SnO2–α-Fe2O3 composite mixtures: exploration of number of active sites, turnover number and turnover frequency

2018 ◽  
Vol 2 (4) ◽  
pp. 796-806 ◽  
Author(s):  
L. Gomathi Devi ◽  
R. Shyamala
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Active Sites ◽  
Separation Process ◽  
Schematic Diagram ◽  
Charge Transfer Process ◽  
Turnover Frequency ◽  
Turnover Number ◽  
Electron Hole ◽  
Uv Visible

Schematic diagram showing energy band edge positions, vectorial charge transfer process and electron hole separation process in the SnO2–α-Fe2O3 composite under UV/visible light irradiation.

scholarly journals Synthesis, characterization and photocatalytic activity of mesoporous Na-doped TiO2 nano-powder prepared via a solvent-controlled non-aqueous sol–gel route

RSC Advances ◽  
2017 ◽  
Vol 7 (85) ◽  
pp. 54053-54062 ◽  
Author(s):  
Inderjeet Singh ◽  
Balaji Birajdar
Keyword(s):  
Photocatalytic Activity ◽  
Catalytic Activity ◽  
Surface Area ◽  
Recombination Rate ◽  
Sol Gel ◽  
Electron Hole ◽  
Photo Catalytic Activity ◽  
Nano Powder ◽  
Hole Recombination ◽  
Enhanced Crystallinity

The superior photo-catalytic activity of mesoporous Na doped TiO2 attributed to the combined effect of electron–hole recombination rate, increased surface area and enhanced crystallinity.

Photo-Deposition of Ag Metal Particles on Ni-Doped TiO2 for Photocatalytic Application

2017 ◽  
Vol 42 (3) ◽  
pp. 244-250 ◽  
Author(s):  
Mohammad Reza Elahifard ◽  
Reza Vatan Meidanshahi
Keyword(s):  
Photocatalytic Activity ◽  
Band Gap ◽  
Metal Particles ◽  
Electron Hole ◽  
Photocatalytic Application ◽  
Negative Effect ◽  
Direct Band ◽  
Indirect Band Gap ◽  
Co Precipitation ◽  
Acid Blue

Ni-doped TiO2 and Ag-deposited@Ni-doped TiO2 photocatalysts were prepared using the co-precipitation technique and characterised using X-ray powder diffraction, scanning electron microscopy and Brunauer–Emmett-Teller analysis. Our results confirmed the presence of Ni atoms in the TiO2 bulk structure and Ag° metal particles deposited on the surface. The Ni impurity generates defect midgap states in the TiO2 band structure, providing visible light (VL) absorption, which are responsible for photocatalytic activity under VL conditions. Against this advantage, Ni changes the indirect band gap of pure anatase to the direct band gap which may dramatically suppress the photocatalytic activity of Ni-doped TiO2. Moreover, Ni may provide a centre of electron–hole (e–h) recombination which enhances the negative effect of Ni impurity on TiO2 photo-efficiency. These drawbacks were overcome by deposition of Ag° on the Ni-doped TiO2 which sinks the photo-excited electrons, quenching e–h recombination. This improvement yields three times more photo-efficiency in the decolourisation of Acid Blue 92. Although Ag@Ni-doped anatase shows a higher adsorption constant ( Kads) than Ag@Ni-doped rutile, both catalysts surprisingly present the same rate constant ( k).

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