The synthesis of MNC5 active site for electrochemical catalysis

Abstract

Metal-nitrogen-carbon (M-N-C) catalysts with M-Nx (x = 2 or 4) sites on graphene substrate are researched intensively nowadays. However, the simple and repetitive hexatomic ring structure of graphene limits the exploration of novel efficient active sites for catalysis. Herein, a new carbon material, hydrogen-substituted graphdiyne (HsGDY), is designed as the substrate to develop new active sites. Benefiting from the unique sp and sp2 hybridized carbon atoms of HsGDY, aromatic rings in HsGDY can fix Fe single atoms, creating novel FeC6 and FeNC5 active sites. The as-synthesized Fe-N-HsGDY catalyst displays much higher activity than commercial Pt/C and is found to be one of the highest activities among the reported non-noble metal catalysts for oxygen reduction reaction (ORR). FeNC5 site with graphitic-N has been verified experimentally and theoretically as an efficient active site for ORR. Those results indicate that the rational choice of specific substrate materials with novel structures will broaden the path of creating new active sites with efficient activity.