scholarly journals Improving Photocatalytic Degradation Activity of Organic Pollutant by Sn4+ Doping of Anatase TiO2 Hierarchical Nanospheres with Dominant {001} Facets

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1603 ◽  
Author(s):  
Meiling Sun ◽  
Weichong Kong ◽  
Yunlong Zhao ◽  
Xiaolin Liu ◽  
Jingyue Xuan ◽  
...  
Keyword(s):  
Light Absorption ◽  
Active Sites ◽  
Organic Pollutant ◽  
Photogenerated Electron ◽  
High Energy ◽  
Charge Carriers ◽  
Photon Absorption ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
Electron Hole

Herein, high-energy {001} facets and Sn4+ doping have been demonstrated to be effective strategies to improve the surface characteristics, photon absorption, and charge transport of TiO2 hierarchical nanospheres, thereby improving their photocatalytic performance. The TiO2 hierarchical nanospheres under different reaction times were prepared by solvothermal method. The TiO2 hierarchical nanospheres (24 h) expose the largest area of {001} facets, which is conducive to increase the density of surface active sites to degrade the adsorbed methylene blue (MB), enhance light scattering ability to absorb more incident photons, and finally, improve photocatalytic activity. Furthermore, the SnxTi1−xO2 (STO) hierarchical nanospheres are fabricated by Sn4+ doping, in which the Sn4+ doping energy level and surface hydroxyl group are beneficial to broaden the light absorption range, promote the generation of charge carriers, and retard the recombination of electron–hole pairs, thereby increasing the probability of charge carriers participating in photocatalytic reactions. Compared with TiO2 hierarchical nanospheres (24 h), the STO hierarchical nanospheres with 5% nSn/nTi molar ratio exhibit a 1.84-fold improvement in photodegradation of MB arising from the enhanced light absorption ability, increased number of photogenerated electron–hole pairs, and prolonged charge carrier lifetime. In addition, the detailed mechanisms are also discussed in the present paper.

scholarly journals A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1039
Author(s):  
Dafu Jiang ◽  
Tunmise Ayode Otitoju ◽  
Yuanyuan Ouyang ◽  
Noor Fazliani Shoparwe ◽  
Song Wang ◽  
...  
Keyword(s):  
Metal Ions ◽  
Active Sites ◽  
Crystal Surface ◽  
Uv Light ◽  
Photogenerated Electron ◽  
Tio2 Photocatalyst ◽  
Electron Hole ◽  
Visible Light Range ◽  
Low Toxicity ◽  
High Chemical Stability

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

scholarly journals Synthesis and characterization of Z-scheme heterostructure CoWO4/g-C3N4 as a visible-light photocatalyst for removal of organic pollutant

2021 ◽  
Vol 10 (2) ◽  
pp. 59-63
Author(s):  
Hai Pham Viet ◽  
Anh Dao Thi Ngoc ◽  
Viet Nguyen Minh ◽  
Ha Tran Thi Viet ◽  
Dang Do Van ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
High Performance ◽  
Organic Pollutant ◽  
Photogenerated Electron ◽  
Morphological Properties ◽  
Electron Hole ◽  
Visible Light Photocatalyst ◽  
Photocatalytic Activities

In this study, direct Z–scheme heterostructure CoWO4/g-C3N4 was synthesized by a facile hydrothermal method. The structural, morphological properties of the prepared samples were characterised by XRD, SEM, UV–Vis and PL measurements. The as-obtained heterostructure CoWO4/g-C3N4 exhibited enhanced photocatalytic activities toward the degradation of Rhodamine B under visible light irradiation with 92% Rhodamine B removal after 80 minutes irritation, which exceeded pristine g-C3N4 and CoWO4. The enhanced photocatalytic performance ascribed to interfacial contact between g-C3N4 and CoWO4, thus further inhibiting the recombination of photogenerated electron/hole pairs. It is anticipated that the construction of Z–scheme heterostructure CoWO4/g-C3N4 is an effective strategy to develop high-performance photocatalysts for the degradation of organic pollutants in water.

scholarly journals Photocatalytic water splitting by N-TiO2 on MgO (111) with exceptional quantum efficiencies at elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yiyang Li ◽  
Yung-Kang Peng ◽  
Liangsheng Hu ◽  
Jianwei Zheng ◽  
Dharmalingam Prabhakaran ◽  
...  
Keyword(s):  
Water Splitting ◽  
Elevated Temperatures ◽  
Practical Method ◽  
Charge Carriers ◽  
Molar Ratio ◽  
Electron Hole ◽  
Photocatalytic Water Splitting ◽  
The Past ◽  
Electron Hole Pair ◽  
Electric Field Polarization

Abstract Photocatalytic water splitting is attracting enormous interest for the storage of solar energy but no practical method has yet been identified. In the past decades, various systems have been developed but most of them suffer from low activities, a narrow range of absorption and poor quantum efficiencies (Q.E.) due to fast recombination of charge carriers. Here we report a dramatic suppression of electron-hole pair recombination on the surface of N-doped TiO2 based nanocatalysts under enhanced concentrations of H+ and OH−, and local electric field polarization of a MgO (111) support during photolysis of water at elevated temperatures. Thus, a broad optical absorption is seen, producing O2 and H2 in a 1:2 molar ratio with a H2 evolution rate of over 11,000 μmol g−1 h−1 without any sacrificial reagents at 270 °C. An exceptional range of Q.E. from 81.8% at 437 nm to 3.2% at 1000 nm is also reported.

scholarly journals Excellent Photocatalytic Rhodamine B Degradation for water Remediation Over Pr3+ Doped Bi2WO6 Microspheres

2021 ◽  
Author(s):  
Xianghui Zhang
Keyword(s):  
Rhodamine B ◽  
Organic Pollutant ◽  
Photogenerated Electron ◽  
Orthorhombic Phase ◽  
Water Remediation ◽  
Doping Amount ◽  
Electron Hole ◽  
Radical Trapping ◽  
One Step ◽  
Xrd Patterns

Abstract In this work, a serious of Pr3+ doped Bi2WO6 had been prepared by one-step hydrothermal method without using any additive. XRD results showed that the Pr3+ doped Bi2WO6 possessed pure orthorhombic phase. XRD patterns shifted to higher angles with the doping amount of Pr3+ increasing indicated that Pr3+ was doped into the lattice of Bi2WO6. UV-vis DRS results revealed that the band gap was narrowed by Pr3+ doping. SEM and TEM images showed that the Pr3+ doped Bi2WO6 presented 3D flower-like microspheres constructed by many nanosheets. The photocatalytic activities of the as-prepared samples were evaluated by using rhodamine B (RhB) as the target organic pollutant. It was found that 1% Pr-Bi2WO6 exhibited excellent photocatalytic performance, as well as good stability and reusability. The improved photocatalytic activity can be ascribed to the optimum optical absorption activity, the larger specific surface area and the morphology of microspheres which resulted in the effective separation of the photogenerated electron hole pairs. In addition, the photocatalytic mechanism had been discussed according to the radical-trapping experiments.

scholarly journals A metal-free 3C-SiC/g-C3N4 composite with enhanced visible light photocatalytic activity

RSC Advances ◽  
2017 ◽  
Vol 7 (63) ◽  
pp. 40028-40033 ◽  
Author(s):  
Hao Xu ◽  
Zhixing Gan ◽  
Weiping Zhou ◽  
Zuoming Ding ◽  
Xiaowei Zhang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Carbon Nitride ◽  
Photocatalytic Performance ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Metal Free ◽  
Visible Light Photocatalytic

Insufficient visible light absorption and fast recombination of the photogenerated electron–hole pairs have seriously hampered the photocatalytic performance of graphitic carbon nitride (g-C3N4) up to now.

Enhanced visible light photocatalytic activity of AgI/TiO2 composite fabricated by a grinding method

2019 ◽  
Vol 54 (3) ◽  
pp. 257-264
Author(s):  
Jin Xu ◽  
Dasheng Gao ◽  
Shuang Cui ◽  
Xiaohua Wang ◽  
Ningning Liu
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Photogenerated Electron ◽  
Active Species ◽  
Electron Hole ◽  
Grinding Method ◽  
The Stability ◽  
Visible Light Photocatalytic

Abstract Through a simple grinding method, AgI/TiO2 composites were successfully synthesized. The as-prepared AgI/TiO2 composites were used as photocatalysts for Rhodamine B (RhB) degradation under visible light irradiation and exhibited excellent photocatalytic performance. In the presence of composites, almost 100% RhB was decomposed after 60 min. The photocatalytic activity of AgI/TiO2-0.5 composite was optimal, which was 9.5 times higher than that of pristine TiO2, and 15.6 times higher than that of AgI. Moreover, experimental results revealed that the improved photocatalytic activity was not only ascribed to the loading AgI but also resulted from the method that enabled the exposure of more active sites in the composites. In addition, the intimate interfacial contact obtained by this method could also promote the efficient separation of photogenerated electron-hole pairs. Moreover, the possible photocatalytic active species and the stability of the photocatalyst were investigated in detail.

scholarly journals Ultra-Thin Carbon-Doped Bi2WO6 Nanosheets for Enhanced Photocatalytic CO2 Reduction

2021 ◽  
Author(s):  
Han Li ◽  
Junchao Zhang ◽  
Jiaguo Yu ◽  
Shaowen Cao
Keyword(s):  
Light Absorption ◽  
Active Sites ◽  
Co2 Reduction ◽  
Charge Recombination ◽  
Charge Carriers ◽  
Carbon Doping ◽  
Defect Engineering ◽  
Carbon Doped ◽  
Promising Strategy ◽  
Thin Carbon

AbstractThe photocatalytic reduction of CO2 is a promising strategy to generate chemical fuels. However, this reaction usually suffers from low photoactivity because of insufficient light absorption and rapid charge recombination. Defect engineering has become an effective approach to improve the photocatalytic activity. Herein, ultra-thin (~ 4.1 nm) carbon-doped Bi2WO6 nanosheets were prepared via hydrothermal treatment followed by calcination. The ultra-thin nanosheet structure of the catalyst not only provides more active sites but also shortens the diffusion distance of charge carriers, thereby suppressing charge recombination. Moreover, carbon doping could successfully extend the light absorption range of the catalyst and remarkably promote charge separation, thus inhibiting recombination. As a result, the as-prepared Bi2WO6 photocatalyst with ultra-thin nanosheet structure and carbon doping exhibits enhanced photocatalytic CO2 reduction performance, which is twice that of pristine ultra-thin Bi2WO6 nanosheet. This study highlights the importance of defect engineering in photocatalytic energy conversion and provides new insights for fabricating efficient photocatalysts.

An inverse opal TiO2/g-C3N4 composite with a heterojunction for enhanced visible light-driven photocatalytic activity

2019 ◽  
Vol 48 (10) ◽  
pp. 3486-3495 ◽  
Author(s):  
Juying Lei ◽  
Bin Chen ◽  
Weijia Lv ◽  
Liang Zhou ◽  
Lingzhi Wang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Absorption Efficiency ◽  
Inverse Opal ◽  
Electron Hole ◽  
Visible Light Absorption ◽  
Visible Light Driven

An inverse opal TiO2/g-C3N4 composite with excellent photogenerated electron–hole separation efficiency and enhanced visible light absorption efficiency was constructed.

The synergistic reaction of Ag deposition and Ce dopant to modify TiO2-based nanomaterials for efficient light photocatalysis

2019 ◽  
Vol 12 (01) ◽  
pp. 1850095 ◽  
Author(s):  
Chenghe Hua ◽  
Xiaoli Dong ◽  
Xiuying Wang ◽  
Xiufang Zhang ◽  
Hongchao Ma
Keyword(s):  
Light Absorption ◽  
Photocatalytic Performance ◽  
Photogenerated Electron ◽  
Simulated Sunlight ◽  
Electron Hole ◽  
Sunlight Irradiation ◽  
Hydrolysis Method ◽  
Optical And Electronic Properties ◽  
Ion Doping ◽  
Ag Deposition

The Ce/TiO2 (Ce/Ti) and Ag/Ce/TiO2 (Ag/Ce/Ti) nanomaterials were successfully synthesized by hydrolysis method. The products were characterized by a variety of characteristic techniques to investigate their phases, morphologies, structures, optical and electronic properties and photocatalytic performance. The DRS, PL and PEC indicated that the introduction of Ce and Ag resulted in a stronger light absorption and an effective charge separation. The photocatalytic performance of both Ce/Ti and Ag/Ce/Ti were evaluated for degrading reactive blue K-NR under simulated sunlight irradiation. The results demonstrated that Ce[Formula: see text] ion doping and Ag deposition synergetic interaction effectively enhance the TiO2 photocatalytic activity ascribed to the improved photogenerated electron–hole pairs separation, enhanced light absorption and large surface area. Considering their good performance, the Ag/Ce/Ti photocatalyst can be applied in organic pollutants treatment in water and environmental purification.

Cooperation effect of heterojunction and co-catalyst in BiVO4/Bi2S3/NiOOH photoanode for improving photoelectrochemical performances

2018 ◽  
Vol 42 (24) ◽  
pp. 19415-19422 ◽  
Author(s):  
Jindong Wei ◽  
Cailou Zhou ◽  
Ying Xin ◽  
Xifei Li ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Water Splitting ◽  
Light Absorption ◽  
Surface Reaction ◽  
Photogenerated Electron ◽  
Photoelectrochemical Water Splitting ◽  
Electron Hole ◽  
Co Catalyst ◽  
Surface Reaction Kinetics

The separation and transport of photogenerated electron–hole pairs as well as wider light absorption and surface reaction kinetics are the main limitations in photoelectrochemical water splitting.

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