Periodic Defect Engineering of Iron-Nitrogen-Carbon Catalysts for Nitrate Electroreduction to Ammonia.

Iron-nitrogen-carbon single atom catalyst (SAC) is regarded as one of the promising electrocatalysts for NO 3 - reduction reaction (NO 3 RR) to NH 3 due to its high activity and selectivity. However, synergistic effects of topological defects and FeN 4 active moiety in Fe-N-C SAC have rarely been investigated. By performing density functional theory (DFT) calculations, 13 defective graphene FeN 4 with 585, 484, and 5775 topological line defects are constructed, yielding 585-68-FeN 4 with optimal NO 3 RR catalytic activity, high selectivity, as well as robust anti-dissolution stability. The high NO 3 RR activity on 585-68-FeN 4 is well explained by the high valence state of Fe center as well as asymmetric charge distribution on FeN 4 moiety influenced by 5- and 8-member rings. This DFT work provides theoretical guidance for engineering NO 3 RR performance of iron-nitrogen-carbon catalysts by modulating periodic topological defects.