Tuning active sites in MoS₂-based catalysts via H₂O₂ etching to enhance hydrodesulfurization performance

A H₂O₂ etching strategy was adopted to introduce coordinatively unsaturated sites (CUS) on MoS₂-based catalysts for dibenzothiophene (DBT) hydrodesulfurization (HDS). The CUS concentrations on MoS₂ slabs were finely regulated by changing the concentrations of H₂O₂ solution. With the increasing H₂O₂ concentrations (0.1–0.3 mol/L), The CUS concentrations on MoS₂ slabs increased gradually. However, the high-concentration H₂O₂ etching (0.5 mol/L) increased the MoOSand MoO₃ contents on MoS₂ slabs compared to etching with the H₂O₂ concentration of 0.3 mol/L, which led to the less CUS concentration in the sulfided Mo–H-0.5 catalyst than in the sulfided Mo–H-0.3 catalyst. A microstructure-activity correlation indicated that the CUS introduced by H₂O₂ etching on MoS₂ slabs significantly enhanced DBT HDS. Different Co loadings were further introduced into Mo–H-0.3, which had the most CUS concentration, and the corresponding 0.2-CoMo catalyst with the highest CoMoS content (3.853 wt%) exhibited the highest reaction rate constant of 6.95 × 10⁻⁶ mol g⁻¹ s⁻¹ among these CoMo catalysts.