ZIF-8-derived mesoporous Mo single-atom active sites catalyst for deep oxidative desulfurization

Oxidative desulfurization (ODS) is a crucial technology for producing clean, sulfur-free fuels. Molybdenum-based catalysts face the challenges of easy shielding of active metal centers and low utilization of active sites. Here, N-rich ligand-anchored mesoporous (9.45 nm) Mo single-atom active sites catalysts were constructed based on the strategy of ZIF-8 via spatial domain restriction using melamine as a pyrolytic agent. Through aberration-corrected HAADF-STEM, XANES, EXAFS and other characterization, Mo atoms were confirmed to be well-dispersed on N-doped carbon matrix. The ODS experiments demonstrated that the catalyst displayed excellent catalytic activity, achieving complete DBT conversion in 30 min under optimal conditions, with a turnover frequency (TOF) number reaching 72.87 h −1 , surpassing most previously reported Mo-based catalysts. Experimental results and computational calculations suggest the dominant role of single-atom MoN 3 sites in activating H 2 O 2 to produce •OH and •O 2 - . The uniformly distributed MoN x part uses the N coordination number to modulate the electronic structure and geometric configuration to promote electron transfer and stabilize the mesoporous structure enhancing the mass transfer of target pollutants. This study elucidates the structure-activity relationship between the coordination microenvironment of active metal centers and ODS performance, offering new insights for the design of highly active Mo-based catalysts. • Mesoporous Mo single-atom active sites catalysts were constructed via the spatial restriction strategy with melamine as a pore expander. • The TOF value of m-Mo SA -N 3 -C is 72.87 h⁻¹ , surpassing most previously reported Mo-based catalysts. • The MoN 3 active site is essential for the generation of •OH and •O 2 - . • The structure-activity relationship between the coordination microenvironment of active metal centers and ODS activity was revealed.