Fe2P@mesoporous carbon nanosheets synthesized via an organic template method as a cathode electrocatalyst for Zn–air batteries

Abstract

Two-dimensional carbon nanomaterials have the advantages of exposing more active sites to reactants and low diffusion resistance, which have drawn enormous attention for their applications in electro-catalysis. In this study, large-sized Fe₂P/N-doped mesoporous carbon nanosheets were facilely prepared from layered organic hybrids via a novel organic crystal-templating method. In this method, the organic crystals played the roles of inflation stripping, constructing a mesoporous structure into nanosheets and nitrogen doping in the carbonization process. The as-prepared carbon nanosheets showed a high catalytic efficiency in terms of onset potential (0.976 V), half-wave potential (0.844 V) and long-term stability for the ORR. DFT calculations showed that the adsorption energies of ORR intermediates on Fe–N were improved by coupling Fe–P. Further to this, the doped carbon nanosheets presented higher voltage efficiency and cycling stability, outperforming commercial noble metal catalysts when applied as a cathode catalyst in a rechargeable Zn–air battery. The universal manufacture technique of carbon nanosheets could be extended to prepare other metal/heteroatom-doped 2D carbon nanomaterials by utilizing various carbon sources.