Cu- and P-co-doped nitrogen-doped hierarchical carbon for enhanced oxygen reduction reaction in zinc–air batteries†

Abstract

High-performance Fe-based nitrogen-doped carbon oxygen reduction catalysts have been widely reported, but the Fenton reaction faced by such catalysts has hindered their practical application in fuel cells. The development of inexpensive, effective, and durable non-Fe nitrogen-doped carbon electrocatalysts is important for advancing fuel cell technology. In this work, we have introduced a molecular coordination chemistry method to synthesize a Cu- and P-co-doped nitrogen-doped hierarchical carbon (Cu–P–N–C) oxygen reduction reaction (ORR) electrocatalyst by pyrolyzing a mixture of phytate and melamine. The refined Cu–P–N–C material showcased a three-dimensional, porous, interconnected nanosheet structure with an ultra-high specific surface area and an abundance of active sites. The Cu–P–N–C catalyst displayed a half-wave potential (E_1/2) of 0.86 V_RHE, higher than that of commercial Pt/C in 0.1 M KOH. It was also found to maintain an impressive long-term stability, retaining 95.4% of its initial activity after extensive testing. When integrated into zinc–air batteries (ZABs), the Cu–P–N–C electrocatalyst was observed to deliver exceptional performance, achieving a high peak power density of 164.5 mW cm⁻², a promising specific capacity of 807 mA h g⁻¹, and remarkable stability. These findings underscore the potential of Cu–P–N–C as a potential candidate for next-generation ORR electrocatalysts in new energy devices.