Synthesis of CdS/CeO2 hetero nanostructures for Photocatalytic H2 production and simultaneous Removal of phenol and Cr(VI)

Nandy, Swarnava and Ch, Subrahmanyam (2014) Synthesis of CdS/CeO2 hetero nanostructures for Photocatalytic H2 production and simultaneous Removal of phenol and Cr(VI). Masters thesis, Indian Institute of Technology, Hyderabad.

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Abstract

Harvesting visible light of the solar spectrum by coupled semiconductor based systems where sensitization of a wide band gap semiconductor with a small band gap semiconductor advantageous for photocatalytic as well as photovoltaic applications. A facile one pot synthesis of several CdS/CeO2 hetero nanostructures has been carried out without using expensive surfactants, capping agents and molecular linkers. Various techniques such as Xray diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance UV-Vis spectroscopy, Raman spectroscopy and BET surface area were used to characterize the samples. XRD and Raman spectroscopic data provided the information about the presence of both CdS and CeO2 phases. TEM proves the proper dispersion and well connectivity between the CdS and CeO2 which may be due to the single step synthesis of the composites. XPS gives the information about the presence of elements such as Cd, Ce, O, S, C and N, where the presence of latter two elements can be attributed to the in-situ C and N doping during the combustion synthesis. UV-visible spectroscopy reveals the absorption in both UV and visible regions due to the presence of both CeO2 and CdS. The visible light activity of the composites have been ascribed by the H2 production from water by using sacrificial reagents, simultaneous removal of phenol and Cr(VI) from aqueous streams. Among the synthesized composites CdS/CeO2 (1:1) has shown superior activity which can be attributed to the optimum sensitization of CeO2 which induces enhanced electron transfer from CdS to CeO2 that decreases the exciton recombination.

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