scholarly journals Photocatalysis and Bandgap Engineering Using ZnO Nanocomposites

2015 ◽  
Vol 2015 ◽  
pp. 1-22 ◽  
Author(s):  
Muhammad Ali Johar ◽  
Rana Arslan Afzal ◽  
Abdulrahman Ali Alazba ◽  
Umair Manzoor
Keyword(s):  
Absorption Spectrum ◽  
Graphene Oxide ◽  
Composite Materials ◽  
Photogenerated Electron ◽  
Photocatalytic Efficiency ◽  
Absorption Band Edge ◽  
Bandgap Engineering ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
Electronic And Structural Properties

Nanocomposites have a great potential to work as efficient, multifunctional materials for energy conversion and photoelectrochemical reactions. Nanocomposites may reveal more improved photocatalysis by implying the improvements of their electronic and structural properties than pure photocatalyst. This paper presents the recent work carried out on photoelectrochemical reactions using the composite materials of ZnO with CdS, ZnO with SnO2, ZnO with TiO2, ZnO with Ag2S, and ZnO with graphene and graphene oxide. The photocatalytic efficiency mainly depends upon the light harvesting span of a material, lifetime of photogenerated electron-hole pair, and reactive sites available in the photocatalyst. We reviewed the UV-Vis absorption spectrum of nanocomposite and photodegradation reported by the same material and how photodegradation depends upon the factors described above. Finally the improvement in the absorption band edge of nanocomposite material is discussed.

NiFe-LDH@ZnO@NF composite for photo-degradation of Rhodamine B dye

MRS Advances ◽  
2019 ◽  
Vol 4 (33-34) ◽  
pp. 1887-1893
Author(s):  
Jun Wu ◽  
Yonghui Gong ◽  
Qiang Fu ◽  
Chunxu Pan
Keyword(s):  
Rhodamine B ◽  
Photocatalytic Performance ◽  
Nickel Foam ◽  
Photogenerated Electron ◽  
Chemical Compositions ◽  
Photocatalytic Efficiency ◽  
Electron Hole ◽  
Photo Degradation ◽  
Potential Applications ◽  
Rhodamine B Dye

ABSTRACTIn this paper, a novel NiFe-LDH@ZnO composite was prepared by using a facile two-step process upon nickel foam (NF) substrate. The morphologies and chemical compositions of the samples were characterized by SEM, EDS, XRD and XPS. Photocatalytic degradation of Rhodamine B dye was tested with the samples NiFe-LDH@ZnO@NF, ZnO@NF and NiFe-LDH under the same conditions. The experimental results revealed that the NiFe-LDH@ZnO@NF composite exhibited excellent photocatalytic performance, i.e., 1.4 and 2.5 times higher than that of pure ZnO and NiFe-LDH, respectively. The reason was that the NiFe-LDH@ZnO@NF composite provided a possibility to effectively inhibit the recombination of the photogenerated electron-hole pairs, and therefore enhanced the photocatalytic efficiency. This composite is expected to have potential applications in wastewater treatment field.

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 Synthesis and Characterization of Amorphous Molybdenum Sulfide (MoSx)/CdIn2S4 Composite Photocatalyst: Co-Catalyst Using in the Hydrogen Evolution Reaction

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1455
Author(s):  
Qi Li ◽  
Wanli Liu ◽  
Xuejian Xie ◽  
Xianglong Yang ◽  
Xiufang Chen ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Separation Efficiency ◽  
Photogenerated Electron ◽  
Molybdenum Sulfide ◽  
Electron Hole ◽  
Composite Photocatalyst ◽  
Co Catalyst ◽  
Pair Separation ◽  
Electron Hole Pair

Co-catalyst deposition is used to improve the surface and electrical properties of photocatalysts. In this work, MoSx/CdIn2S4 nanocomposites were prepared by a facile hydrothermal and photodeposition route. The basic crystalline phases and morphology of the as-prepared samples were determined, and these results showed that MoSx was tightly anchored onto CdIn2S4 by sharing the same S atom. In the hydrogen production experiments, MoSx/CdIn2S4-40 displayed the optimal photocatalytic hydrogen production yield in 4 h. The H2 evolution rate reached 2846.73 μmol/g/h, which was 13.6-times higher than that of pure CdIn2S4. Analyzing the photocatalytic enhancement mechanisms revealed that this unique structure had a remarkable photogenerated electron-hole pair separation efficiency, rapid charge carrier transfer channels, and more abundant surface reaction sites. The use of co-catalyst (MoSx) greatly improved the photocatalytic activity of CdIn2S4.

Construction of a novel Cu2(OH)3F/g-C3N4 heterojunction as a high-activity Fenton-like catalyst driven by visible light

2021 ◽  
Author(s):  
Lifen Wang ◽  
Yinjun Lin ◽  
Wenting Guo ◽  
Yuanyuan Yang ◽  
Ruiqin Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
High Activity ◽  
Photogenerated Electron ◽  
Hole Pair ◽  
Competitive Effect ◽  
Electron Hole ◽  
Fenton Reagents ◽  
Pair Separation ◽  
Electron Hole Pair

Inhibiting the competitive effect of O2 in copper-based Fenton reagents and improving the photogenerated electron–hole pair separation of g-C3N4 are the focus of current research.

Self-assembly and enhanced visible-light-driven photocatalytic activity of reduced graphene oxide-Bi2WO6 photocatalysts

2017 ◽  
Vol 6 (6) ◽  
pp. 505-516 ◽  
Author(s):  
Hongguang Yu ◽  
Chenglin Chu ◽  
Paul K. Chu
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Self Assembly ◽  
Electron Transition ◽  
Blue Shift ◽  
Electron Hole ◽  
Reduced Graphene ◽  
Visible Light Driven ◽  
Electron Hole Pair

AbstractThe reduced graphene oxide-Bi2WO6 (rGO-BWO) photocatalysts with different RM values (mass ratio of GO and Bi2WO6) had been successfully synthesized via hydrothermal method in the presence of GO. When increasing the RM values from 0 to 2%, the evident red shift of the absorption edges of rGO-BWO samples occurred, and the photocatalytic activities for the degradation of Rhodamine-B were enhanced gradually. However, there was a significant blue shift in the absorbance band, and the morphology of the incomplete rGO-BWO microspheres led to the lower photocatalytic activity when RM is increased from 4 to 10%. The enhanced photocatalytic activity can be attributed to the smaller band gap, which means needing less energy for the electron transition, the morphology of the unbroken microsphere that provides more possible reaction sites for the photocatalytic reaction, the appropriate GO content that may effectively mitigate electron-hole pair recombination by the migration of photoinduced electrons.

Behavior of Photogenerated Electron–Hole Pair for Water Splitting on TiO2(110)

2018 ◽  
Vol 122 (40) ◽  
pp. 22930-22938 ◽  
Author(s):  
Fan Jin ◽  
Min Wei ◽  
Tingwei Chen ◽  
Huizhong Ma ◽  
Guokui Liu ◽  
...  
Keyword(s):  
Water Splitting ◽  
Photogenerated Electron ◽  
Hole Pair ◽  
Electron Hole ◽  
Electron Hole Pair

scholarly journals Preparation and photocatalytic hydrogen evolution of g-C3N4/ZnO composite

2020 ◽  
Vol 165 ◽  
pp. 05007
Author(s):  
Shenghua Ma ◽  
Wanxi Wang
Keyword(s):  
Absorption Band ◽  
Visible Light ◽  
Production Rate ◽  
Hydrogen Evolution ◽  
Analytical Methods ◽  
Photogenerated Electron ◽  
Red Shift ◽  
Band Edge ◽  
Absorption Band Edge ◽  
Electron Hole

The photocatalytic composite of g-C3N4/ZnO with different g-C3N4 content have been prepared by thermopolymerization method. The catalysts are characterized and analyzed by SEM, XRD, UV-Vis, BET and other analytical methods. The results show that g-C3N4/ZnO composites caused the red shift of the absorption band edge of ZnO, which increased the absorption of visible light and the separation rate of photogenerated electron-hole pairs. It is found that the H2 production rate of 25% g-C3N4/ZnO sample is best with 306.25 μmol∙h-1∙g-1, which is 4.6 times higher than of g-C3N4.

Graphene oxide as a structure-directing agent for the two-dimensional interface engineering of sandwich-like graphene–g-C3N4 hybrid nanostructures with enhanced visible-light photoreduction of CO2 to methane

2015 ◽  
Vol 51 (5) ◽  
pp. 858-861 ◽  
Author(s):  
Wee-Jun Ong ◽  
Lling-Lling Tan ◽  
Siang-Piao Chai ◽  
Siek-Ting Yong
Keyword(s):  
Graphene Oxide ◽  
Visible Light ◽  
Hole Pair ◽  
Hybrid Nanostructures ◽  
Two Dimensional ◽  
Interface Engineering ◽  
Electron Hole ◽  
Structure Directing Agent ◽  
Electron Hole Pair

Graphene–g-C3N4 demonstrated high visible-light photoactivity of CO2 reduction to CH4, which was ascribed to the inhibition of electron–hole pair recombination by graphene.

Enhanced visible light driven photocatalytic activity of CdO–graphene oxide heterostructures for the degradation of organic pollutants

2018 ◽  
Vol 42 (5) ◽  
pp. 3246-3259 ◽  
Author(s):  
Jahangir Ahmad ◽  
Kowsar Majid
Keyword(s):  
Photocatalytic Activity ◽  
Graphene Oxide ◽  
Visible Light ◽  
Organic Pollutants ◽  
Charge Separation ◽  
Photogenerated Electron ◽  
Electron Hole ◽  
Oxide Heterostructures ◽  
Visible Light Driven ◽  
Suppressed Recombination

Synthesis of efficient CdO based photocatalysts for enhanced visible light driven photocatalytic degradation of organic pollutants mostly emphasize on (1) increase of surface area of the photocatalyst and (2) high charge separation and suppressed recombination of photogenerated electron–hole pairs.

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