Layered Confinement Reaction: Atomic-level Dispersed Iron-Nitrogen Co-Doped Ultrathin Carbon Nanosheets for CO2 Electroreduction.

High electrochemical over-potential and low product selectivity are regarded as the main limitations of electroreduction of CO2 . Here, we proposed a new strategy to synthesize metal porphyrin-hybridized porous and ultra-thin carbon nanosheets (MPPCN) by the confinement function of the layered template. The layered confinement reaction protects the coordination structure of metal and nitrogen atoms during subsequent high-temperature treatment while ensuring the formation of ultra-thin structures. This method effectively prevents the aggregation of metal atoms, so that the metal atoms exhibit a dispersed state of a single atomic level. MPPCN exhibit unexpected catalytic activity for electroreduction of CO2 , and the catalytic reaction can be carried out at an over-potential of 0.39 V. The faradaic efficiency of CO can reach 95.9 % at the potential of -0.7 V versus the reversible hydrogen electrode.