Activity descriptor of Ni,N-Codoped carbon electrocatalyst in CO2 electroreduction reaction

Nickel, nitrogen-codoped carbon materials (Ni,N-C) are flourishing as high-efficiency electrocatalysts for CO2 electroreduction reaction (CO2RR). Nevertheless, the preparation of Ni,N-C electrocatalysts with high performance towards CO2RR is still blind, without any guidelines, due to the lack of defined and available activity descriptor. Herein, we explored the correlation between the ratio of N species and CO2RR activity with taking a series of well-defined Ni,N-C materials as representative electrocatalysts. By smartly utilizing the ratio of Ni-N specie as an activity descriptor, the correlation between the ratio of N specie (Ni-N) and CO partial current density over all samples presents a well volcanic trend. At the optimal ratio of Ni-N specie, a high CO Faradaic efficiency (FE) of 94.8 % can be achieved with a good stability for 29 h. More significantly, the activity range for a library of Ni,N-C electrocatalysts for CO2RR is distinctly divided according to the activity descriptor.