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.

To improve oil quality, ZSM-22/SAPO-11 composite molecular sieves were synthesized by adding ZSM-22 into a synthetic gel of SAPO-11 for n-decane hydroisomerization. The mass ratios of ZSM-22/(ZSM-22+SAPO-11) in the composite molecular sieves were optimized and the optimal ZSM-22/SAPO-11 composite (ZS-9) was obtained. The electrostatic repulsions between the ZSM-22 precursors and the SAPO-11 crystalline nuclei produced small ZSM-22 and SAPO-11 crystallites in ZS-9, which increased the specific surface area and mesopore volume and thereby exposed more acid sites. In comparison with conventional SAPO-11, ZSM-22 and their mechanical mixture, ZS-9 with smaller crystallites and the optimal medium and strong Brønsted acid centers (MSBAC) content displayed a higher yield of branched C₁₀ isomers (81.6%), lower cracking selectivity (11.9%) and excellent stability. The correlation between the i-C₁₀ selectivity and the MSBAC density of molecular sieves indicated that the selectivity for branched C₁₀ isomers first increased and then decreased with increasing MSBAC density on the molecular sieves, and the maximum selectivity (87.7%) occurred with a density of 9.6 × 10⁻² μmol m⁻².