Tungsten-doped TiO 2 /reduced Graphene Oxide nano-composite photocatalyst for degradation of phenol: A system to reduce surface and bulk electron-hole recombination

2017 ◽  
Vol 203 ◽  
pp. 364-374 ◽  
Author(s):  
Manisha Yadav ◽  
Asha Yadav ◽  
Rohan Fernandes ◽  
Yaksh Popat ◽  
Michele Orlandi ◽  
...  
2019 ◽  
Vol 19 (11) ◽  
pp. 7089-7096 ◽  
Author(s):  
Wufa Li ◽  
Xiaohong Yang ◽  
Haitao Fu ◽  
Xizhong An ◽  
Haiyang Zhao

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.


Author(s):  
Nor Shuhada Alim ◽  
Hendrik O. Lintang ◽  
Leny Yuliati

Reduced graphene oxide (rGO) has been one of the most investigated carbon based materials due to its great electronic conductivity that make it able to accept and transport electron easily. In order to study the effect of rGO, anatase titanium dioxide-reduced graphene oxide (TiO2-rGO) composite was prepared by UV-assisted photocatalytic reduction method using the anatase TiO2 as a photocatalyst and various different loadings of graphene oxide (GO). The characterizations of the prepared samples were investigated by X-ray diffractometer (XRD), Fourier transform infrared (FTIR), and fluorescence spectroscopies. The XRD patterns and FTIR spectra confirmed that all the TiO2-rGO composites samples were successfully synthesized without disrupting the structure of the anatase TiO2. Fluorescence spectroscopy revealed the role of the rGO to reduce the electron-hole recombination on the anatase TiO2. In the photocatalytic removal of phenol, all the TiO2-rGO composites showed better photocatalytic activities than the bare anatase TiO2 under UV light irradiation. The activity of the anatase TiO2 was enhanced by more than four times with the addition of the GO with the optimum amount (3 wt%). It was proposed that the good photocatalytic performance obtained on the composites were caused by the successful suppression of electron-hole recombination by the rGO on the TiO2.


2018 ◽  
Vol 937 ◽  
pp. 17-23
Author(s):  
Wu Fa Li ◽  
Xiao Hong Yang ◽  
Hai Tao Fu ◽  
Xi Zhong An

Photogenerated electron/hole recombination greatly limits the catalytic efficiency of TiO2, and recently modification with graphene substance has been regarded as an effective way to enhance the photocatalytic performance of TiO2. When referring to the fabrication of graphene based materials, the reduction process of graphene oxide has been demonstrated to be a key step. Therefore, it is highly required to develop an efficient and simple route for the GO reduction and the formation of TiO2-reduced graphene oxide (RGO) nanocomposites. In this study, TiO2-RGO nanocomposites were prepared by a facile and efficient one-step hydrothermal method using titanium (IV) butoxide (TBT) and graphene oxide (GO) without reducing agents. This method shows several unique features, including no requirement of harsh chemicals and high temperature involved, one-step hydrothermal reaction for mild reduction of GO and crystallization of TiO2 running in parallel, and the production of TiO2-RGO nanocomposites in a green and efficient synthetic route. In addition, the photocatalytic activities of the synthesized composites were systematically evaluated by degrading methylene blue (MB) under sun light irradiation. The TiO2-RGO nanocomposites show a superior photocatalytic activity to the synthesized pure TiO2. It is also found that the concentration of RGO in the nanocomposites plays a key role in the photocatalytic activity. Specifically, the composite with 1 wt % RGO shows the best photocatalytic activity, probably due to the reduction of the electron-hole recombination rate.


RSC Advances ◽  
2016 ◽  
Vol 6 (65) ◽  
pp. 60318-60326 ◽  
Author(s):  
Long Zhang ◽  
Lan Sun ◽  
Shuai Liu ◽  
Yuhong Huang ◽  
Kewei Xu ◽  
...  

The MoS2/rGO exhibits enhanced photocatalytic activity for degradation of RhB due to effective separation of photo-generated electron–hole pairs by heterointerface.


RSC Advances ◽  
2016 ◽  
Vol 6 (66) ◽  
pp. 61312-61318 ◽  
Author(s):  
Meng Li ◽  
Xiulin Fan ◽  
Xuezhang Xiao ◽  
Xu Huang ◽  
Yiqun Jiang ◽  
...  

NiTiO3/reduced graphene oxide (RGO) nano-composite was first synthesized and introduced as anode materials for LIBs. The NiTiO3/RGO exhibits a higher capacity than bare NiTiO3 materials over 50 cycles.


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