A hybrid density functional study on the visible light photocatalytic activity of (Mo,Cr)–N codoped KNbO3

2015 ◽  
Vol 17 (43) ◽  
pp. 28743-28753 ◽  
Author(s):  
Guangzhao Wang ◽  
Hong Chen ◽  
Yang Li ◽  
Anlong Kuang ◽  
Hongkuan Yuan ◽  
...  

To improve the photocatalytic performance of KNbO3 for the decomposition of water into hydrogen and oxygen, the electronic structure of KNbO3 should be modified to have a suitable bandgap with band edge positions straddling the water redox level so as to sufficiently absorb visible light.

2017 ◽  
Vol 41 (16) ◽  
pp. 8140-8155 ◽  
Author(s):  
Francis Opoku ◽  
Krishna Kuben Govender ◽  
Cornelia Gertina Catharina Elizabeth van Sittert ◽  
Penny Poomani Govender

A hybrid ternary ZnS/GO/ZnO(001) system achieved enough driving force for splitting water into H2 gas.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Yan Gong ◽  
Hongtao Yu ◽  
Xie Quan

Recently a novel sliver oxide Ag3AsO4has been found to be an excellent photocatalyst with strong oxidation capability for pollutant degradation under visible light. But the origin of its high visible light photocatalytic activity was unclear which hindered further research of Ag3AsO4. For clarifying that, the electronic structure and optical properties of Ag3AsO4have been analyzed by the hybrid density functional method. The results reveal that the Ag3AsO4presents a narrow band gap with strong oxidation ability of the valence bands maximum edge and the highly delocalized charge distribution of the conduction bands minimum is beneficial for the carriers transfer to surface to participate in the photocatalytic reaction. These results provide clear explanations of the excellent visible light photocatalytic performance of the Ag3AsO4from microscopic aspect. And it is significant to design novel materials with high photocatalytic performance.


2021 ◽  
Author(s):  
Yumeng Fo ◽  
Yanxia Ma ◽  
Hao Dong ◽  
Xin Zhou

Codoping with cation and anion is found to be an effective approach to tailor the electronic structures of semiconductor-based photocatalysts. In this work, a systematic hybrid density functional study has...


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3948
Author(s):  
Lingfang Qiu ◽  
Zhiwei Zhou ◽  
Mengfan Ma ◽  
Ping Li ◽  
Jinyong Lu ◽  
...  

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min−1 to 0.022 min−1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.


2017 ◽  
Vol 19 (36) ◽  
pp. 24915-24927 ◽  
Author(s):  
A. H. Reshak

The amalgamation of a wide optical band gap photocatalyst with visible-light-active CdO quantum dots (QDs) as sensitizers is one of the most efficient ways to improve photocatalytic performance under visible light irradiation.


Nanomaterials ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 579 ◽  
Author(s):  
Xiaojuan Chen ◽  
Ning Li ◽  
Runliang Zhu ◽  
Shuai Li ◽  
Chunmo Yu ◽  
...  

Novel Z-Scheme CuBi2O4/β-Bi2O3 composite photocatalysts with different mass ratios and calcination temperatures were firstly synthesized by the hydrothermal method following a temperature-programmed process. The morphology, crystal structure, and light absorption properties of the as-prepared samples were systematically characterized, and the composites exhibited enhanced photocatalytic activity toward diclofenac sodium (DS) degradation compared with CuBi2O4 and β-Bi2O3 under visible light irradiation. The optimal photocatalytic efficiency of the composite, achieved at the mass ratio of CuBi2O4 and β-Bi2O3 of 1:2.25 and the calcination temperature of 600 °C is 92.17%. After the seventh recycling of the composite, the degradation of DS can still reach 82.95%. The enhanced photocatalytic activity of CuBi2O4/β-Bi2O3 is closely related to OH•, h+ and O2•−, and the photocatalytic mechanism of CuBi2O4/β-Bi2O3 can be explained by the Z-Scheme theory.


RSC Advances ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 6114-6120 ◽  
Author(s):  
Junpeng Ren ◽  
Yongyong Zhu

Ag2O doped electrospun BiVO4 nanofibers with p–n junction heterogeneous structures show enhanced photocatalytic activity under visible light (photocatalytic efficiency: 98.47% within 100 min) and good cycling stability.


2020 ◽  
Vol 7 (1) ◽  
pp. 191539 ◽  
Author(s):  
Takamasa Ishigaki ◽  
Yusuke Nakada ◽  
Naoki Tarutani ◽  
Tetsuo Uchikoshi ◽  
Yoshihiro Tsujimoto ◽  
...  

Nano-size EVONIK AEROXIDE ® P25 titanium dioxide, TiO 2 , powder was heat-treated at temperatures, 700–900°C, in air. An X-ray diffraction study showed that the P25 powder is composed of approximately 20 and approximately 80 mass% of rutile and anatase phases, respectively. It was also shown that the transformation from anatase to rutile induced by high-temperature heat treatment was almost completed at 750°C, whereas a small amount (less than 3 mass%) of anatase phase was still left even in the powder heat-treated at 900°C. The transformation behaviour was consistent with results obtained by Raman scattering spectroscopy. Raman experiments also indicated that high-temperature heating induced the formation of oxide ion vacancies. Powders were dispersed in methyl orange (MO) aqueous solution, and the bleach rate of MO was measured to evaluate photocatalytic activity under ultraviolet (UV)- and visible-light irradiation. After the heat treatment, the UV-light photocatalytic performance sharply deteriorated. Interestingly, visible-light photocatalytic activity was enhanced by high-temperature heating and reached the highest performance for an 800°C-heated sample, indicating that the P25 powder obtained high visible-light photocatalytic performance after heat treatment. Even after 900°C heat treatment, the photocatalytic performance was higher than that of as-received powder. Enhancement of photocatalytic activities was discussed in relation to visible light absorption and charge carrier transfer.


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