Defects Mediate the Active N Sites in N-doped Carbon Catalyst for Efficiently Catalyzing H2S to Element Sulfur

The catalytic oxidation of H 2 S into element sulfur using nanocarbon materials is an effective means to solve environmental pollution and realize resource utilization of sulfur. Defect engineering and heteroatom doping are effective strategies for tuning the electronic structure of carbon materials to enhance their catalytic performance. Therefore, rationally exploiting the synergistic effects between defects and heteroatom sites, and elucidating the underlying catalytic mechanisms are essential for the development of high-performance carbon-based catalysts. In this study, we design and synthesize a series of N-doped carbon catalysts containing structural defects, which exhibit significantly enhanced desulfurization performance. Experimental results demonstrate that the NDC-700 catalyst exhibits excellent catalytic activity (95.0% H 2 S conversion and 94.4% S selectivity at 190 °C) and stability (>80   h) while maintaining high performance with high O 2 partial pressures and in the presence of impurity gases such as steam, CO 2 , and CO under mild conditions in continuous mode (≤ 200 °C). XPS analysis, kinetic studies, and oxygen activation experiments reveal that the catalytic performance improves with increasing defect density, despite a decrease in pyridinic N content. DFT calculations further indicate that defect structures substantially alter the local charge distribution around pyridinic N sites, promoting the adsorption and activation of H 2 S and O 2 , ultimately improving catalytic performance. This study elucidates the synergistic interaction between defects and N sites, and further confirms the critical role of defects in enhancing the catalytic function of N-doped carbon materials.