An ultra-dispersive, nonprecious metal MOF–FeZn catalyst with good oxygen reduction activity and favorable stability in acid

Abstract Development of the more stable nonprecious oxygen reduction reaction (ORR) catalyst is of great significance nowadays. Herein, a high-performance iron-doped integral uniform macrocyclic organic framework (MOF–FeZn) catalyst is synthesized through a combined hydrothermal and pyrolysis process, showing favorable ORR activity and stability in acid. This as-synthesized MOF–FeZn catalyst displays high porous and graphitic structures with sufficient catalytic active dopants of pyridinic N, Fe–N, pyrrolic N, graphitic N, making it a promising ORR candidate catalyst with high electrochemical stability. The onset potential, half-wave potential and limited diffusion current density of MOF–FeZn are 0.93 V @ 0.1 mA cm⁻², 0.768 V@ 2.757 mA cm⁻² and 5.5 mA cm⁻², respectively, which are comparable to the state-of-the-art nonprecious catalyst and commercial Pt/C. ORR catalysis on MOF–FeZn follows the nearly four-electron path. What is more, MOF–FeZn can sustain the 10,000 cycles electrochemical potential cycling process in acid with the half-wave potential changed only 21 mV, superior to the reduction of 149 mV for Pt/C. The well-developed integral uniform structures, homogeneously dispersed carbides and nitrides protected by the highly graphitic carbon layers and the better agglomeration suppression of nanoparticles by the confined graphitic carbon layers on catalyst can significantly enhance the catalytic activity and stability of MOF–FeZn.