Ultra-stable catalyst for enhanced electrocatalytic CO₂ reduction: g-C₃N₄-derived porous C/N-modified ZnNi₂O₄

Efficient conversion of carbon dioxide is a key approach to mitigating climate change and promoting carbon neutrality. However, current electrocatalysts face challenges such as insufficient activity, low selectivity, and poor long-term stability, which limit their practical application potential. To address these issues, this study designed and synthesized an ultra-stable catalyst (ZnNi₂O₄-CN) by using g-C₃N₄ as a precursor, which decomposed under high temperatures and modified the surface of ZnNi₂O₄ with the residue C and N. The unique spherical structure and synergistic effect between Zn and Ni enable the as-prepared catalyst to achieve a Faradaic efficiency (FE) of CO as high as 92.8% at − 1.17 V (vs. RHE), demonstrating excellent selectivity. Furthermore, the catalyst exhibited a slow FE_CO decline trend after 12 h of constant potential electrolysis. Comparative XPS fine spectral analysis before and after the reaction revealed no significant changes in the elemental composition and valence states of the catalyst, indicating its robust structural integrity and strong stability. The design of C- and N-modified bimetallic spinel, combined with the use of organic electrolytes, provides new insights and directions for achieving high-selectivity CO₂ reduction.