Effects of the support Brønsted acidity on the hydrodesulfurization and hydrodenitrogention activity of sulfided NiMo/Al2O3 catalysts

Abstract

Through switching the deposition of MoS3 nanoparticles onto the support with the impregnation of the support with a NH4F solution, two typical F-doped bimetallic NiMoS2/Al2O3 catalysts exhibiting nearly the same compositions, textural properties, chemical state and micromorphology but only one containing some Brønsted (B) acid sites on the alumina surface were first prepared. And then the effects of the support B acidity on hydrodesulfurization (HDS) and hydrodenitrogeneration (HDN) activity were comprehensively studied using representative quinoline (Q) and dibenzothiophene (DBT) as the model reactants, respectively. After comparing the “structure-function” relations of the two bimetallic catalysts, an electronic effect of the support B acid sites on the edge sites of their neighboring MoS2 nanoslabs was suggested. This electronic effect could not only bring about the easier formation of CUS, but also enhance the acidity of SH species. This dual effect greatly promotes the HDS and HDN activities. Besides, the B acid sites also help the catalysts exhibit a certain isomerization activity, which further enhances the HDS performance.