pH-Controlled photocatalytic abatement of RhB by an FeWO4/BiPO4 p–n heterojunction under visible light irradiation

2019 ◽  
Vol 43 (44) ◽  
pp. 17241-17250
Author(s):  
Nithya Mahendran ◽  
Sathya Udayakumar ◽  
Keerthi Praveen
Keyword(s):  
Electric Field ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Separation Efficiency ◽  
Light Irradiation ◽  
The Novel ◽  
Electron Hole ◽  
Ph Controlled

The novel FeWO4/BiPO4 heterojunction generates an inner electric field to promote electron–hole separation efficiency and is a proficient photocatalyst.

scholarly journals Tunable Synthesis of Ultrathin BiOCl 2D Nanosheets for Efficient Photocatalytic Degradation of Carbamazepine upon Visible-Light Irradiation

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shuo Xu ◽  
Xiaoya Gao ◽  
Wenfeng Xu ◽  
Pengfei Jin ◽  
Yongmei Kuang
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Electron Hole ◽  
Magnetic Stirring ◽  
Degradation Activity

A series of ultrathin BiOCl 2D nanosheet photocatalysts were prepared by the TBAOH-assisted hydrolysis method in water. The effects of tetrabutylammonium hydroxide (TBAOH) dosages, chlorine source, preparation pH value, ultrasonic treatment, and magnetic stirring on the photocatalytic degradation dynamics of carbamazepine were examined under visible-light irradiation to optimize the preparation parameters. It was found that ultrathin BiOCl prepared with TBAOH dosages of 1 mmol and chlorine source of NaCl in the pH of 2 upon magnetic stirring of 6 h displayed the highest photocatalytic degradation rate constant (0.0038 min−1) of carbamazepine, which is 7.6 times higher than that with the ordinary BiOCl (without TBAOH). To clarify the mechanism on the outstanding photocatalytic activity of ultrathin BiOCl, the elemental composition/state, micromorphology, and separation efficiency of photogenerated electron-hole pairs were investigated by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and photoluminescence (PL). Results showed that the presence of oxygen vacancy, ultrathin nanosheet structure, and improved separation efficiency of photogenerated electron-hole pairs contributed to the excellent photocatalytic degradation activity of ultrathin BiOCl. The obtained result provides a novel method to fabricate ultrathin BiOCl with excellent photocatalytic degradation activity of carbamazepine under visible-light irradiation.

A simple method to synthesise Ag-doped TiO2 photocatalysts with different Ag0:Ag2O atomic ratios for enhancing visible-light photocatalytic activity

2017 ◽  
Vol 41 (8) ◽  
pp. 475-483 ◽  
Author(s):  
C. Chen ◽  
X. F. Lei ◽  
M. Z. Xue
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Absorption ◽  
Separation Efficiency ◽  
Visible Region ◽  
Light Irradiation ◽  
Electron Hole ◽  
X Ray

Pure anatase TiO2 photocatalysts with different Ag contents were prepared via a simple sol-gel method. The as-prepared anatase Ag-doped TiO2 photocatalysts were characterised by X-ray diffraction, transmission electron microscopy, UV-Vis diffuse reflectance spectra, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, thermal gravity and differential thermal analysis, scanning electron microscopy and N2 adsorption–desorption measurements (BET). Compared with pure TiO2, Ag-doped anatase TiO2 photocatalysts exhibited not only increases in light absorption in the visible region, the separation efficiency of electron–hole pairs and surface area, but also inhibition of the titania phase transition from anatase to rutile. Photoreduction results showed that Ag-doped anatase TiO2 photocatalysts have greatly improved photocatalytic activity, compared with pure TiO2, and the reduction of Cr(VI) under visible light irradiation was much higher than that of pure TiO2. The optimum Ag content was 1.0 mol%, which led to the complete reduction of Cr(VI) under visible light irradiation (λ > 420 nm) for 4 h. The enhanced photocatalytic activity was attributed to the synergic effect of the pure anatase structure, and the increased light absorption in the visible region, separation efficiency of electron–hole pairs and atomic ratio of Ag0:Ag2O.

Synthesis of g-C3N4/CuS Heterojunction with Enhanced Photocatalytic Activity Under Visible-Light

2020 ◽  
Vol 20 (9) ◽  
pp. 5896-5905
Author(s):  
Fan Wang ◽  
Qingru Zeng ◽  
Jinping Tang ◽  
Liang Peng ◽  
Jihai Shao ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Separation Efficiency ◽  
Photocatalytic Property ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Electron Hole ◽  
Photocatalytic System ◽  
Composite Photocatalysts ◽  
The Stability

Novel g-C3N4/CuS hybrid photocatalysts were synthesized successfully via a facile hydrothermal method. Characterization results of the photocatalysts showed that especial heterostructure had formed between g-C3N4 and CuS, and possess suitable matched band potential. The composite photocatalysts displayed strong UV-visible light absorption ability in the range from 200 to 800 nm. Photocatalytic performance of the photocatalysts were evaluated via photooxidation of methyl orange (MO) under visible-light irradiation. Hybrid photocatalysts showed better photocatalytic properties than that of pure g-C3N4 or CuS. The 60% g-C3N4/CuS sample proved the supreme photocatalytic property. The integrated g-C3N4 and CuS heterojunction elevated the separation efficiency of photogenerated electron–hole pairs, and increased the photo-decoloration efficiency of MO under visible-light irradiation. A four-cycle repeatability experiment was carried out to investigate the stability of hybrid photocatalysts in the photocatalyst reaction. Radical capture experiments proved that photogenerated e−, h+ and .OH were responsible for MO photo-decoloration. In addition, the potential mechanism of the photocatalytic system g-C3N4/CuS+H2O2+vis are presented.

scholarly journals Synthesis of Ag and AgCl co-doped ZIF-8 hybrid photocatalysts with enhanced photocatalytic activity through a synergistic effect

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 698-704 ◽  
Author(s):  
Yanqiu Jing ◽  
Qiang Lei ◽  
Chun Xia ◽  
Yu Guan ◽  
Yide Yang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Synergistic Effect ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Separation Efficiency ◽  
Light Irradiation ◽  
Electron Hole ◽  
Dye Pollutants ◽  
High Separation ◽  
Co Doped

Recently, Ag/AgCl composites with different structures have been widely studied and used as photocatalysts to degrade dye pollutants, due to their high separation efficiency of electron–hole pairs under visible light irradiation.

scholarly journals Synthesis, Analysis, and Testing of BiOBr-Bi2WO6Photocatalytic Heterojunction Semiconductors

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xiangchao Meng ◽  
Zisheng Zhang
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Degradation Process ◽  
Light Irradiation ◽  
Enhancement Effect ◽  
Electron Hole ◽  
Experimental Conditions ◽  
Synthesis Conditions ◽  
Optimum Synthesis ◽  
Photocatalytic Activities

In photocatalysis, the recombination of electron-hole pairs is generally regarded as one of its most serious drawbacks. The synthesis of various composites with heterojunction structures has increasingly shed light on preventing this recombination. In this work, a BiOBr-Bi2WO6photocatalytic heterojunction semiconductor was synthesized by the facile hydrothermal method and applied in the photocatalytic degradation process. It was determined that both reaction time and temperature significantly affected the crystal structure and morphologies of the photocatalysts. BiOBr (50 at%)-Bi2WO6composites were prepared under optimum synthesis conditions (120°C for 6 h) and by theoretically analyzing the DRS results, it was determined that they possessed the suitable band gap (2.61 eV) to be stimulated by visible-light irradiation. The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation ofRhodamine B (RhB)under visible-light irradiation. The experimental conditions, including initial concentration, pH, and catalyst dosage, were explored and the photocatalysts in this system were proven stable enough to be reused for several runs. Moreover, the interpreted mechanism of the heterojunction enhancement effect proved that the synthesis of a heterojunction structure provided an effective method to decrease the recombination rate of the electron-hole pairs, thereby improving the photocatalytic activity.

Boosting the photocatalytic performance of (001) BiOI: enhancing donor density and separation efficiency of photogenerated electrons and holes

2016 ◽  
Vol 52 (30) ◽  
pp. 5316-5319 ◽  
Author(s):  
Wenjie Fan ◽  
Haibo Li ◽  
Fengyi Zhao ◽  
Xujing Xiao ◽  
Yongchao Huang ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Photocatalytic Performance ◽  
Separation Efficiency ◽  
Light Irradiation ◽  
Donor Density ◽  
Photogenerated Electrons ◽  
Bioi Nanosheets

BiOI nanosheets with highly exposed (001) and surface disorders are used for efficient photocatalytic HCHO oxidation under visible light irradiation.

Synthesis of Bi-deficient monolayered Bi2WO6 nanosheets with enhanced photocatalytic activity under visible light irradiation

2019 ◽  
Vol 9 (5) ◽  
pp. 1178-1188 ◽  
Author(s):  
Taiping Xie ◽  
Yaoyu Zhang ◽  
Weiyuan Yao ◽  
Yue Liu ◽  
Haiqiang Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Hydroxyl Groups ◽  
Electron Hole ◽  
Photoexcited Electron

The strong protonated hydroxyl groups around Bi vacancies could efficiently promote the separation of photoexcited electron–hole pairs.

Plasmon-Induced Photodegradation of Toxic Pollutants with Ag/AgI/Bi2WO6 under Visible-Light Irradiation

2013 ◽  
Vol 807-809 ◽  
pp. 1534-1542 ◽  
Author(s):  
Ming Sheng Gui ◽  
Peng Fei Wang ◽  
Miao Miao Tang ◽  
Dong Yuan
Keyword(s):  
Surface Plasmon Resonance ◽  
Visible Light ◽  
Surface Plasmon ◽  
Visible Light Irradiation ◽  
Plasmon Resonance ◽  
Photogenerated Electron ◽  
Light Irradiation ◽  
Ag Nps ◽  
Electron Hole ◽  
Band Position

The Ag/AgI/Bi2WO6photocatalysts were successfully synthesized by deposition-precipitation and photoreduction methods. The catalyst showed high and stable photocatalytic activity for the degradation of the RhB under visible light irradiation (λ>400 nm). On the basis of a new plasmonic photocatalytic mechanism, the photogenerated electron-hole pairs are formed in Ag nanoparticles (NPs) due to surface plasmon resonance under visible-light irradiation. Then, the photoexcited electrons at the Ag NPs are injected into AgI. On the other hand, the band position shows that AgI and Bi2WO6have the matching band potentials in the AgI/Bi2WO6heterostructure composites. So the photoexcited electrons is ultimately transfer to the Bi2WO6conduction band (CB), photo-induced holes (hVB+) is transfer to the AgI valence band (VB) and the simultaneous transfer to compensative electrons from I-to the Ag NPS. This the result indicates that the high photosensitivity of noble metal Ag NPs due to surface plasmon resonance, which is not only improve the photocatalytic performance, but also offer a new idea for preparation of new photocatalysts .

scholarly journals Enhanced Transformation of Atrazine by High Efficient Visible Light-Driven N, S-Codoped TiO2Nanowires Photocatalysts

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Yanlin Zhang ◽  
Honghai Wu ◽  
Peihong Liu
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Advanced Oxidation Process ◽  
Light Irradiation ◽  
Solar Irradiation ◽  
Electron Hole ◽  
Toc Removal ◽  
High Efficient ◽  
Endocrine Disrupting ◽  
Visible Light Driven

Advanced oxidation process using titanium dioxide as a photocatalyst under solar irradiation is one of the most attractive technologies to eliminate atrazine, an endocrine disrupting and carcinogen contaminant. The N, S-codoped TiO2nanowires at the calcination of 600°C obtained by a facile hydrothermal method revealed the best photocatalytic performance for the degradation of atrazine under visible light irradiation compared to N, S-codoped TiO2nanoparticles and S-doped TiO2nanowires. TOC removal experiment also exhibited the similar result and achieved 63% of atrazine mineralization within 6 h. The degradation of atrazine was driven mainly by•OH and holes during the photocatalytic process. Reactive species quantities such•OH andO2•-generated by N, S-codoped TiO2nanowires under visible light irradiation were much more than those of S-doped TiO2nanowires and N, S-codoped TiO2nanoparticles. These results were mainly attributed to the synergistic effect of N and S doping in narrowing the band gap, remarkable increase in electron-hole separation, extending the anatase-to-rutile transformation temperature above 600°C, and preferentially exposing high reactive{001}crystal facets of anatase.

Effective removal of colourless pollutants and organic dyes by Ag@AgCl nanoparticle-modified CaSn(OH)6 composite under visible light irradiation

2017 ◽  
Vol 41 (13) ◽  
pp. 5334-5346 ◽  
Author(s):  
Chao Liang ◽  
Cheng-Gang Niu ◽  
Xiao-Ju Wen ◽  
Shi-Feng Yang ◽  
Mao-Cai Shen ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Absorption ◽  
Organic Dyes ◽  
Light Irradiation ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Effective Removal ◽  
Agcl Nanoparticles

The Ag@AgCl nanoparticles could broaden visible-light absorption of pure CSH and depress the recombination of photoinduced electron–hole pairs.

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