Metal-free porous N, S co-doped carbon catalyst for H2S selective oxidation: enhanced elemental sulfur selectivity and mechanisms

The selective oxidation of H 2 S into elemental sulfur is considered as one promising method for the removal of this undesired gas. Second heterogeneous atom introducing into N doped carbocatalyst skeleton shows their potential on the enhancement of selectivity. We developed a novel N, S co-doped porous carbon with high pyridinic content and mesoporous pore structure for H 2 S selective oxidation. The experimental results showed that the optimized catalyst exhibits excellent durability about 133 h with 100 % conversion and 95 % elemental sulfur selectivity at 180 °C. Kinetic study and density functional theory calculation reveals that sulfur doping could regulate the electronic structure of N atom on the carbocatalyst surface and further weaken the interactions between N active site and H 2 S molecule, then prevent deep oxidation of H 2 S. The work provides a strategy for atomic-level modulation of non-metal doping catalysts, enabling selective oxidation process for efficient and durable desulfurization.