Optimizing CO production in electrocatalytic CO₂ Reduction via electron accumulation at Ni Sites in Ni₃ZnC_0.7/Ni on N-doped carbon nanofibers

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 Ni₃ZnC_0.7/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 Ni₃ZnC_0.7/Ni@CNFs system facilitates rapid electron transfer to CO₂, resulting in great performance with a faradaic efficiency for CO (FE_CO) of nearly 90% at -0.86 V vs. the reversible hydrogen electrode (RHE) and a current density of 17.51 mA cm^-2 at -1.16 V vs. RHE in an H-cell. Furthermore, the catalyst exhibits remarkable stability, maintaining its crystal structure and morphology after 50 hours of electrolysis. Moreover, the Ni₃ZnC_0.7/Ni@CNFs is used in the membrane electrode assembly reactor (MEA), which can achieve a FE_CO 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.