Highly Active and Sulfur-Resistant Fe-N4Sites in Porous Carbon Nitride for the Oxidation of H2S into Elemental Sulfur

Iron-based catalysts have been widely studied for the oxidation of H2S into elemental S. However, the prevention of iron sites from deactivation remains a big challenge. Herein, a facile copolymerization strategy is proposed for the construction of isolated Fe sites confined in polymeric carbon nitride (CN) (Fe-CNN chi). The as-prepared Fe-CNN chi catalysts possess unique 2D structure as well as electronic property, resulting in enlarged exposure of active sites and enhancement of redox performance. Combining systematic characterizations with density functional theory calculation, it is disclosed that the isolated Fe atoms prefer to occupy four-coordinate doping configurations (Fe-N-4). Such Fe-N(4)centers favor the adsorption and activation of O(2)and H2S. As a consequence, Fe-CNN chi exhibit excellent catalytic activity for the catalytic oxidation of H2S to S. More importantly, the Fe-CNN chi catalysts are resistant to water and sulfur poisoning, exhibiting outstanding catalytic stability (over 270 h of continuous operation), better than most of the reported catalysts.