Rapid synthesis of nano-scale CeO2 by microwave-assisted sol–gel method and its application for CH3SH catalytic decomposition

A time-saving and efficient method, which is microwave-assisted sol–gel method, by using citric acid as a chelating agent, has been employed to synthesize CeO2 nanoparticles as a high-performance catalyst for CH3SH catalytic decomposition. Microwave-assisted sol–gel process is superior in terms of shortening reaction time, and a viscous gel can be obtained with the aid of uniform and rapid heating process within several minutes. Combined with N2 adsorption–desorption, TEM, XRD, H2-TPR and XPS results, CeO2 nanoparticles obtained by microwave-assisted sol–gel method exhibited larger surface area and smaller crystallite size than that prepared by conventional sol–gel method. The method should be beneficial to form more lattice oxygen species and more structural defects, which are in favor of CH3SH catalytic decomposition. TPS results illustrated that CeO2-based catalysts were typical sulfur absorbents at high temperature. According to the characterization results of XPS and XRD, various Ce–O–S compounds including cerium sulfide (Ce2S3) and cerium sulfate (Ce(SO4)2) were formed after the relevant reactions between CeO2 and gaseous sulfur species, and the formation of Ce2S3 in the later period of reaction might cause severe decline of the catalytic activity.

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