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.

几十年来，CoMoS或NiMoS催化剂已在商业上用于加氢脱硫（HDS）和加氢脱氮（HDN）反应。但是，关于反应机制的见解仍在争论中。同时，通常认为基面对于HDS或HDN反应是惰性的，从而使催化剂的大表面积无用。因此，构建了六个边缘和四个表面模型作为HDS和HDN催化剂，以系统地研究可能的活性位点的反应性和选择性。除了活性边缘位点，我们的结果表明，MoS ₂基面的反应性通过引入孤立的Co原子可以大大改善催化剂，Co原子可以促进空位的产生并形成Co-S-Mo键。尤其是，新型金属空位界面被证明是用于HDS和HDN反应的有希望的催化模型，其中Co原子和硫空位的协同作用可以促进S / NC键的断裂和氢化过程。这项详细的研究通过结合边缘和表面活性位，为最大化MoS ₂基催化剂的效率铺平了道路。