Tailoring the interactions of heterostructured Ni4N/Ni3ZnC0.7 for efficient CO2 electroreduction

Abstract

Electrocatalytic CO2 reduction into CO has been regarded as one of the most promising strategies for sustainable carbon cycles at ambient conditions, but still faces challenges to achieve both high product selectivity and large current density. Here, we report a Ni4N/Ni3ZnC0.7 heterostructured electrocatalyst embedded in accordion-like N-doped carbon through a simple molten salt annealing strategy. The optimal Ni4N/Ni3ZnC0.7 electrocatalyst achieves a high CO Faraday efficiency of 92.3% and a large total current density of −15.8 mA cm−2 at −0.8 V versus reversible hydrogen electrode, together with a long-term stability about 30 h. Density functional theory results reveal that the energy barrier for *COOH intermediate formation largely decreased on Ni4N/Ni3ZnC0.7 heterostructure compared with Ni4N and Ni3ZnC0.7, thus giving rise to enhanced activity and selectivity. A rechargeable Zn-CO2 battery is further assembled with Ni4N/Ni3ZnC0.7 catalyst as the cathode, which shows a maximum power density of 0.85 mW cm−2 and excellent stability.