A combinatorial descriptor for volcano relationships of electrochemical nitrogen reduction reaction

Abstract

Though touted as a potential way to realize clean ammonia synthesis, electrochemical ammonia synthesis is currently limited by its catalytic efficiency. Great effort has been made to find catalysts with improved activity toward electrochemical nitrogen reduction reaction (eNRR). Rational screening of catalysts can be facilitated using the volcano relationship between catalytic activity and adsorption energy of an intermediate, namely, the activity descriptor. In this work, we propose ΔG*NH2+ΔG*NNH as a combinatorial descriptor, which shows better predictive power than traditional descriptors using the adsorption free energies of single intermediates. The volcano plots based on the combinatorial descriptor exhibits peak activity fixedly at the descriptor value corresponding to the formation free energy of NH3, regardless of the catalyst types; while the descriptor values correspond to the top activities for eNRR on volcano plots based on single descriptors usually vary with the types of catalysts.