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.

scholarly journals Experimental Study of CO2 Conversion into Methanol by Synthesized Photocatalyst (ZnFe2O4/TiO2) Using Visible Light as an Energy Source

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 163 ◽  
Author(s):  
Numair Manzoor ◽  
Muhammad Sadiq ◽  
Muhammad Naqvi ◽  
Umair Sikandar ◽  
Salman Raza Naqvi
Keyword(s):  
Titanium Dioxide ◽  
Global Warming ◽  
Visible Light ◽  
Band Gap ◽  
Zinc Ferrite ◽  
Maximum Yield ◽  
Hole Pair ◽  
Electron Hole ◽  
Bet Analysis ◽  
Electron Hole Pair

Ozone layer depletion is a serious threat due to the extensive release of greenhouse gases. The emission of carbon dioxide (CO2) from fossil fuel combustion is a major reason for global warming. Energy demands and climate change are coupled with each other. CO2is a major gas contributing to global warming; hence, the conversion of CO2 into useful products such as methanol, formic acid, formaldehyde, etc., under visible light is an attractive topic. Challenges associated with the current research include synthesizing a photocatalyst that is driven by visible light with a narrow band gap range between 2.5 and 3.0 eV, the separation of a mixed end product, and the two to three times faster recombination rate of an electron–hole pair compared with separation over yield. The purpose of the current research is to convert CO2 into useful fuel i.e., methanol; the current study focuses on the photocatalytic reduction of CO2into a useful product. This research is based on the profound analysis of published work, which allows the selection of appropriate methods and material for this research. In this study, zinc ferrite (ZnFe2O4) is synthesized via the modified sol–gel method and coupled with titanium dioxide (TiO2). Thereafter, the catalyst is characterized by Fourier transform infrared (FTIR), FE-SEM, UV–Vis, and XRD characterization techniques. UV–Vis illustrates that the synthesized catalyst has a low band gap and utilizes a major portion of visible light irradiation. The XRD pattern was confirmed by the formation of the desired catalyst. FE-SEM illustrated that the size of the catalyst ranges from 50 to 500 nm and BET analysis determined the surface area, which was 2.213 and 6.453 m2/g for ZnFe2O4 and ZnFe2O4/TiO2, respectively. The continuous gas flow photoreactor was used to study the activity of the synthesized catalyst, while titanium dioxide (TiO2) has been coupled with zinc ferrite (ZnFe2O4) under visible light in order to obtain the maximum yield of methanol as a single product and simultaneously avoid the conversion of CO2 into multiple products. The performance of ZnFe2O4/TiO2was mainly assessed through methanol yield with a variable amount of TiO2 over ZnFe2O4 (1:1, 1:2, 2:1, 1:3, and 3:1). The synthesized catalyst recycling ability has been tested up to five cycles. Finally, we concluded that the optimum conditions for maximum yield were found to be a calcination temperature of ZnFe2O4at 900 °C, and optimum yield was at a 1:1 w/w coupling ratio of ZnFe2O4/TiO2. It was observed that due to the enhancement in the electron–hole pair lifetime, the methanol yield at 141.22 μmol/gcat·h over ZnFe2O4/TiO2was found to be 7% higher than the earlier reported data.

Preparation and Characterization of Ag/TiO2-xNx Nanoparticles

2007 ◽  
Vol 534-536 ◽  
pp. 105-108
Author(s):  
Zhong Qing Liu ◽  
Zheng Hua Li ◽  
Yan Ping Zhou ◽  
Chang Chun Ge
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Ultraviolet Light ◽  
Hole Pair ◽  
Electron Hole ◽  
Photoexcited Electron ◽  
Photochemical Deposition ◽  
Electron Hole Pair

The Ag/TiO2-xNx nanoparticles were synthesized by photochemical deposition with irradiation of visible light in a TiO2-XNX suspension system. The prepared products were characterized by means of XRD, Uv-vis, and FEM. Its photocatalytic activity was investigated by the decomposition of methylene blue (MB) solution under illumination of visible and ultraviolet light, respectively. Compared to TiO2-xNx, the photocatalytic activity of as–prepared Ag/TiO2-xNx is obviously enhanced due to the decreasing recombination of a photoexcited electron-hole pair. The mechanism in which photocatalytic activity is enhanced is discussed in detail.

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.

scholarly journals A Facile Synthesis of Visible-Light Driven Rod-on-Rod like α-FeOOH/α-AgVO3 Nanocomposite as Greatly Enhanced Photocatalyst for Degradation of Rhodamine B

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 392 ◽  
Author(s):  
Meng Sun ◽  
Raja Senthil ◽  
Junqing Pan ◽  
Sedahmed Osman ◽  
Abrar Khan
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Rhodamine B ◽  
Diffuse Reflectance Spectroscopy ◽  
Hole Pair ◽  
Precipitation Method ◽  
Aqueous Environment ◽  
Electron Hole ◽  
X Ray ◽  
Electron Hole Pair

In this work, we have synthesized the rod-on-rod–like α-FeOOH/α-AgVO3 nanocomposite photocatalysts with the different amounts of solvothermally synthesized α-FeOOH nanorods via a simple co-precipitation method. The as-synthesized photocatalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, UV−Visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM), element mapping, high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS) analysis. The observed SEM images show that both α-AgVO3 and α-FeOOH exhibits the rod-shaped morphology with nano size. Furthermore, the photocatalytic activities of the obtained photocatalysts were evaluated towards the degradation of Rhodamine B (RhB) under visible-light irradiation. It is demonstrated that the 3 mg α-FeOOH added to the α-FeOOH/α-AgVO3 nanocomposite exhibited an enhanced photocatalytic performance as compared with the pure α-AgVO3 and α-FeOOH. This significant improvement can be attributed to the increased photo-excited electron-hole pair separation efficiency, large portion of visible-light absorption ability and the reduced recombination of the electron-hole pair. The recycling test revealed that the optimized nanocomposite exhibited good photostability and reusability properties. In addition, the believable photodegradation mechanism of RhB using α-FeOOH/α-AgVO3 nanocomposite is proposed. Hence, the developed α-FeOOH/α-AgVO3 nanocomposite is a promising material for the degradation of organic pollutants in an aqueous environment.

scholarly journals Synthesis of Magnetic α-Fe2O3/Rutile TiO2 Hollow Spheres for Visible-Light Photocatalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 396
Author(s):  
Zhongli Zhou ◽  
Hang Yin ◽  
Yuling Zhao ◽  
Jianmin Zhang ◽  
Yahui Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Recombination Rate ◽  
Hydrothermal Reaction ◽  
Hollow Spheres ◽  
Hole Pair ◽  
Experimental Result ◽  
Electron Hole ◽  
Rutile Tio2 ◽  
High Thermodynamic Stability ◽  
Electron Hole Pair

The high recombination rate of the electron-hole pair on the surface of rutile TiO2 (RT) reduces its photocatalytic performance, although it has high thermodynamic stability and few internal grain defects. Therefore, it is necessary for RT to develop effective methods to reduce electron-hole pair recombination. In this study, magnetic α-Fe2O3/Rutile TiO2 self-assembled hollow spheres were fabricated via a facile hydrothermal reaction and template-free method. Based on the experimental result, phosphate concentration was found to play a crucial role in controlling the shape of these hollow α-Fe2O3/RT nanospheres, and the optimal concentration is 0.025 mM. Due to a heterojunction between α-Fe2O3 and RT, the electron-hole pair recombination rate was reduced, the as-synthesized hollow α-Fe2O3/RT nanospheres exhibited excellent photocatalysis in rhodamine B (RhB) photodegradation compared to α-Fe2O3 and RT under visible-light irradiation, and the degradation rate was about 16% (RT), 60% (α-Fe2O3), and 93% (α-Fe2O3/RT) after 100 min. Moreover, α-Fe2O3/RT showed paramagnetism and can be recycled to avoid secondary environmental pollution.

scholarly journals Lattice distortion inducing electron-hole pair condensation in two dimensional systems

2016 ◽  
Vol 726 ◽  
pp. 012013
Author(s):  
Do Thi Hong Hai ◽  
Nguyen Thi Giang ◽  
Nguyen Huu Nha ◽  
Phan Van Nham
Keyword(s):  
Lattice Distortion ◽  
Hole Pair ◽  
Two Dimensional ◽  
Electron Hole ◽  
Electron Hole Pair ◽  
Pair Condensation
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