In Situ Growth of α-MoC Nanoparticles on Bamboo-Structured Carbon Nanotubes as Proton-Feeding Centers of the Fe Site, Achieving Efficient Oxygen Reduction Reaction in Multiple Environments

Abstract

Oxygen reduction reaction (ORR) is a key component of the next generation energy storage system, and most of the current research on ORR catalysts focuses on promoting the rapid conversion process of oxygen-containing intermediates, but its reaction kinetics is also severely limited by the laborious and slow proto-coupled electron transfer (PCET) process. Therefore, it is imperative to develop a high-performance ORR catalyst that can simultaneously accelerate the rapid conversion of PCET and oxygen-containing intermediates. In this context, we purposely grew α-MoC nanoparticles (Fe-MoC@NCNT) in situ on Fe and N codoped bamboo-structured carbon nanotubes to realize the simultaneous promotion of rapid conversion of oxygen intermediates and PCET process. According to the theoretical study, the adjacent α-MoC nanoparticles accelerate the dissociation of water and can act as the proton supply center of Fe–N₄ active site to promote the PCET process, while the oxygenated intermediates can achieve rapid transformation in the Fe–N₄ active site in order to reduce the reaction barrier of the, ORR. Due to the synergistic effect of Fe–N₄ active site and α-MoC, Fe-MoC@NCNT exhibits excellent ORR properties in both alkaline and neutral environments with half-wave potentials of 0.895 and 0.744 V, respectively. Using Fe-MoC@NCNT as the negative catalyst, the assembled aluminum-air battery has a high-power peak rate density of 285.7 mW cm^–2. This work elucidates the method of constructing adjacent proton-supplying centers to optimize the ORR kinetics of single atomic sites and proposes ideas for the synthesis of low-cost and excellent performance ORR catalysts.