Abstract
Activated alumina-based composite oxide support is a commonly used support in hydrodesulfurization (HDS) catalysts, which not only retains the performance advantages of each component in the composite oxide support, but also significantly improves the defects of a single activated alumina support, such as the strong metal-support force of interaction. In this study, NiO-Al2O3 composite support was prepared by introducing NiO-modified Al2O3, and MoS2/NiO-Al2O3 catalysts were prepared for the hydrodesulfurization of COS by liquid phase reduction method. In the COS hydrogenation reaction, the MoS2/NiO-Al2O3 catalyst achieved complete conversion of COS at 220 °C and showed more than 99.9% H2S selectivity. In stability tests, the catalyst maintained a COS conversion of over 99% throughout the 23-hour hydrogenation reaction. Various characterization results show that the NiO-Al2O3 composite support prepared by introducing NiO-modified Al2O3 weakens the metal-support interaction force between MoS2 and NiO-Al2O3 composite support, which is conducive to the synthesis of MoS2 with multilayer and long wafer structures. And it can significantly increase the formation rate of MoS2 to 87.9%, which greatly improves the active site content of the catalyst. Furthermore, the dual modulation of MoS2 and Al2O3 by NiO modulated the surface alkalinity of the catalysts and promoted the formation of a large number of active edge sites in the MoS2/NiO-Al2O3 catalysts, which in turn significantly improved the HDS performance of the catalysts. In addition, EPR characterization combined with experiments showed that the sulfur vacancies are the active sites for catalytic COS hydrodesulfurization over MoS2-based catalysts.
Published Version
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