Water Film Theory-Guided Design of MgO@Carbon Nanoflowers for Room-Temperature H2S-Oxidation: Synergistic Effect Enabling Ultrahigh Carbon Utilization

Extensive research has been conducted on the selective catalytic oxidation of hazardous H2S to elemental sulfur at room temperature using base-loaded carbon catalysts. However, practical applications of these catalysts are hindered by economic and environmental constraints associated with the complex synthesis and activation of functional carbon substrates. Understanding the synergistic mechanism between carbon and bases is crucial for developing innovative catalysts with low carbon content. Herein, molecular simulations were first employed to elucidate the adsorption preferences and reaction pathways within the water film theory, confirming the carbon-MgO interface as the active catalytic site. Furthermore, the ultrathin hierarchically porous carbon layer was demonstrated to effectively mitigate catalyst deactivation by maintaining reaction channels and facilitating product diffusion. Guided by the theoretical insights, nanoflower catalysts were successfully constructed with precisely controlled carbon coating content. Remarkably, MgO@C-0.1 with only 16.7 wt % carbon content exhibited an exceptional sulfur capacity of 4.32 g H2S g-1 cat. This unprecedented carbon utilization efficiency stems from interfacial carbon defects, enhanced mass transport through the ultrathin carbon layer, and abundant sulfur storage space outside nanosheets. This study provides fundamental design principles for exploiting the catalytic potential of carbon and offers inspiring perspectives for developing high-performance catalysts with low carbon footprint.