Optimizing CO production in electrocatalytic CO2 reduction via electron accumulation at Ni sites in Ni3ZnC0.7/Ni on N-doped carbon nanofibers

Abstract

The electrocatalytic reduction of carbon dioxide (CO2RR) to valuable products presents a promising solution for addressing global warming and enhancing renewable energy storage. Herein, we construct a novel Ni3ZnC0.7/Ni heterostructure electrocatalyst, using an electrospinning strategy to prepare metal particles uniformly loaded on nitrogen-doped carbon nanofibers (CNFs). The incorporation of zinc (Zn) into nickel (Ni) catalysts optimizes the adsorption of CO2 intermediates, balancing the strong binding affinity of Ni with the comparatively weaker affinity of Zn, which mitigates over-activation. The electron transfer within the Ni3ZnC0.7/Ni@CNFs system facilitates rapid electron transfer to CO2, resulting in great performance with a faradaic efficiency for CO (FECO) of nearly 90% at −0.86 V versus the reversible hydrogen electrode (RHE) and a current density of 17.51 mA cm−2 at −1.16 V versus RHE in an H-cell. Furthermore, the catalyst exhibits remarkable stability, maintaining its crystal structure and morphology after 50 h of electrolysis. Moreover, the Ni3ZnC0.7/Ni@CNFs is used in the membrane electrode assembly reactor (MEA), which can achieve a FECO of 91.7% at a cell voltage of −3 V and a current density of 200 mA cm−2 at −3.9 V, demonstrating its potential for practical applications in CO2 reduction.