Study on the reaction mechanism of SO₂ hydrogenation over Mo‐based catalyst

Abstract

Mo-based catalysts are widely used for the SO 2 hydrogenation process. However, the detailed reaction mechanism is still unclear and some details should be further supplemented. In this article, the SO 2 hydrogenation processes over the Mo-based catalyst were systematically studied. Several technologies including temperatureprogrammed experiments, isotope-tracing experiment, fourier transform infrared spectroscopy, and switching experiment were adopted to investigate the reaction steps. The results indicated that during the SO 2 hydrogenation process there were three reaction processes containing six steps: First SO 2 would adsorb on the active sites, which could start at relatively low temperature. Then the adsorbed SO 2 would react with H 2 and gradually form elemental sulfur that could be strongly anchored with S atoms of the MoS 2 surface. Afterward, the sulfur further reacted with H 2 to generate H 2 S. Alongside with the consumption of S atoms, the sulfur would be reduced and the active sites was recovered, thus starting the next reaction cycle.