self-assembly of molybdenum carbide and iron carbide heterostructures on N-doped carbon for an efficient oxygen reduction reaction.

Identifying highly stable, cost-effective, platinum-free, and efficient electrocatalysts for the oxygen reduction reaction (ORR) remains a formidable challenge. The ORR is important for advancing fuel cell and zinc-air battery (ZAB) technologies towards cost-efficiency and environmental sustainability. This work presents the utilization of economically viable materials through a straightforward synthesis process, exhibiting the development of efficient MoC/FeC-NC catalysts ingeniously derived from phosphomolybdic acid (PMA) and iron phthalocyanine (FePc). The results demonstrate that the optimized MoC/FeC-NC3 catalysts exhibit remarkable electrochemical performance, evidenced by an impressive onset potential of ∼1.0 V RHE, a half-wave potential of 0.89 V, and a superior current density of about 6.2 mA cm. As for their performance in ZABs, the optimized catalysts reach a peak power density of 142 mW cm at a current density of 200 mA cm. This synergy, coupled with the uniform distribution of MoC and FeC nanoparticles, greatly enhances the active catalytic sites and promotes electrolyte diffusion. Our approach diverges from traditional methods by employing an self-assembled heterostructure of MoC/FeC on nitrogen-doped carbon tubes, avoiding the conventional high-temperature hydrogen gas reduction process. Beyond serving as feasible alternatives to commercially available Pt/C catalysts, these materials hold promise for large-scale production owing to their affordability and the simplicity of the synthesis technique. Such a breakthrough paves the way towards the realization of sustainable energy technologies and lays the groundwork for further exploration into amplifying the scalability and efficiency of ORR catalysts.