Microwave-assisted rapid synthesis of CeO2 nanoparticles and its desulfurization processes for CH3SH catalytic decomposition

• Nano-CeO2 samples were synthesized rapidly by microwave-assisted sol–gel method.
• Nano-CeO2 exhibited high catalytic activity for CH3SH decomposition.
• The formation of Ce2S3 was the main reason for the catalyst deactivation.
• The spent catalysts could be regenerated with air at a short regeneration time.

A simple and convenient route, which is microwave-assisted sol–gel method, is employed to rapidly synthesize CeO2 nanoparticles. The obtained samples exhibited high activity for CH3SH catalytic decomposition, and the influence of synthetic conditions on the catalytic performance has also been comprehensively investigated. Optimum preparation conditions in this study include: calcination temperature of 500 °C, calcination time of 2 h, the molar ratio of cerium salt/citrate of 1/1 and microwave time of 10 min. Catalysts with large surface area and small crystallite size can be obtained under the optimum synthetic conditions, and they can provide more structural defects/oxygen vacancies as well as active sites, which are in favor of CH3SH catalytic decomposition. In addition, it has been shown that CeO2 catalyst can easily react with gaseous sulfur species to form cerium sulfide (Ce2S3) and various Ce–O–S phases during the desulfurization processes. The formation of Ce2S3 on the spent CeO2 samples mainly accounts for the deactivation. The spent catalysts can be successfully regenerated with air for many times at a short regeneration time of 10 min.

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