Sulfide hydrodesulfurisation catalysts: structure of the active component and mechanism of the catalytic action

A new phenomenon in heterogeneous catalysis, namely, oxidative addition of hydrogen to active metal atoms (Ni, Co) within sulfide hydrodesulfurisation catalysts, is considered. The possibility of hydrogen occlusion into the MoS₂ matrix of the active components of these catalysts is demonstrated. The electronic structure of Ni(IV) and Co(III) active sites with d6 electronic configuration is analysed. The concerted mechanism of thiophene hydrogenolysis on a bimetallic active site is considered and substantiated. The concept of the governing role of the metal–sulfur bond energy in catalysis by metal sulfides is analysed critically.