Reversible assembly of Cu4X sites to integrate a dynamic reaction pathway for electrochemical nitrate reduction

Abstract

Electrochemical nitrate reduction to ammonia plays an important role in developing new-type energy conversion technologies, which is however facing the difficulty of complex reaction kinetics and high rate-limiting potentials. Distinct from traditional nanostructures, herein, we suggest a reversible assembly of Cu₄X (X = F, Cl, Br, I) by anchoring X ions in electrolyte onto the Cu surfaces, in which the X ion migration and redistribution during nitrate reduction reaction can effectively regulate the Gibbs free energies of rate-limiting intermediates, finally leading to a reintegration of the switchable reaction pathway. More interestingly, the anchored I atom with a lower diffusion energy than other halogens can donate some additional charges to the adjacent Cu sites in favor of the electronic delocalization and then enhance its antibonding interactions with the rate-limiting reactions. This work offers a reversible atomic assembly strategy to integrate some dynamic reactive site nets that sheds light on designing new-type catalysts.