In order to explore the M−N−C catalysts to replace noble-metal catalysts, Cu-based catalysts with different structures were obtained by pyrolysis of ZIFs with different structures precursors. Their structure-activity relationship was investigated. The results show that the Cu−NC-8 catalyst has abundant Cu−N active sites and N-doped carbon. The N atoms doped with the carbon backbone can adjust the electron density of adjacent C atoms, which is more conducive to the adsorption of O₂ on the electrocatalyst and improves the reaction rate.

Abstract

Cu−N−C catalysts with nitrogen-coordinated copper supported on carbon exhibits good catalytic performance in oxygen reduction reaction (ORR) and is considered as an excellent substitute for Pt catalyst. Achieving high electrocatalytic activity with low amount of copper is critical for improving the performance and reducing the cost of fuel cells. Here, we propose a Cu−NC-8 catalyst, using zeolitic-imidazolate-framework (ZIF), which is rich in N-coordination, as the precursor. High -emperature pyrolysis of the ZIF-8 provides metal anchored sites in the carbon skeleton, which promotes the construction of Cu−N active centers by the introduced Cu. The N-coordination also adjust the electron density of the C atoms to promote the adsorption of O₂ on the catalyst, which is beneficial to the ORR activity of 4e⁻ pathway. The 2.5 % Cu−NC-8 electrocatalyst shows high efficiency ORR activity (E _onset=1.0 V and E _1/2=0.82 V) and good stability.