Edge promotion and basal plane activation of MoS2 catalyst by isolated Co atoms for hydrodesulfurization and hydrodenitrogenation

Abstract

Abstract CoMoS or NiMoS catalysts have been commercially used for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) reactions for decades. However, insight into the reaction mechanism is still under debate. Meanwhile, the basal planes are generally regarded as inactive for HDS or HDN reactions, leaving large surface areas of the catalysts useless. Therefore, six edge and four surface models as HDS and HDN catalysts are constructed to investigate the reactivity and selectivity of possible active sites systematically. In addition to active edge sites, our results demonstrate that the reactivity of basal planes of MoS2 catalysts can be largely improved by incorporating isolated Co atoms, which promote vacancy generation and form Co S Mo bonds. In particular, a novel metal vacancy interface is proven to be a promising catalytic model for HDS and HDN reactions, in which the synergistic effect of Co atom and sulfur vacancy can promote the breakage of S/N C bond and hydrogenation process. This detailed study paves the way of maximization of the efficiency of MoS2 based catalysts by combining both edge and surface active sites.