Regulation of multilayer long crystalline MoS2 by NiO-modified Al2O3 for improved hydrodesulfurization of COS

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-Al 2 O 3 composite support was prepared by introducing NiO-modified Al 2 O 3 , and MoS 2 /NiO-Al 2 O 3 catalysts were prepared for the hydrodesulfurization of COS by liquid phase reduction method. In the COS hydrogenation reaction, the MoS 2 /NiO-Al 2 O 3 catalyst achieved complete conversion of COS at 220 °C and showed more than 99.9% H 2 S selectivity. In stability tests, the catalyst maintained a COS conversion of over 99% throughout the 23-h hydrogenation reaction. Various characterization results show that the NiO-Al 2 O 3 composite support prepared by introducing NiO-modified Al 2 O 3 weakens the metal-support interaction force between MoS 2 and NiO-Al 2 O 3 composite support, which is conducive to the synthesis of MoS 2 with multilayer and long wafer structures. And it can significantly increase the formation rate of MoS 2 to 87.9%, which greatly improves the active site content of the catalyst. Furthermore, the dual modulation of MoS 2 and Al 2 O 3 by NiO modulated the surface alkalinity of the catalysts and promoted the formation of a large number of active edge sites in the MoS 2 /NiO-Al 2 O 3 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 MoS 2 -based catalysts.