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

Abstract

• Well-defined Ni,N-C catalysts with finely tunable N species were developed. • The correlation between the content of N specie and CO 2 RR activity was built. • The ratio of Ni-N specie can be used as an activity descriptor of Ni,N-C catalysts. • The universality of activity descriptor for Ni,N-C catalysts was confirmed. Nickel, nitrogen-codoped carbon materials (Ni,N-C) are flourishing as high-efficiency electrocatalysts for CO 2 electroreduction reaction (CO 2 RR). Nevertheless, the preparation of Ni,N-C electrocatalysts with high performance towards CO 2 RR 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 CO 2 RR 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 CO 2 RR is distinctly divided according to the activity descriptor.