Cobalt-based multicomponent embedded in biomass-derived porous biochar as a highly efficient oxygen reduction reaction electrocatalyst

Abstract The oxygen reduction reaction (ORR) is pivotal for energy conversion systems such as metal-air batteries and fuel cells, yet the development of cost-effective and efficient catalysts remains a challenge. This study introduces a cobalt-based multicomponent catalyst embedded in nitrogen-doped biochar derived from biomass, synthesized via a scalable pyrolysis process using 1,10-phenanthroline as a nitrogen source and chelating agent. The optimized catalyst of WPC-950 demonstrated superior ORR performance with a half-wave potential of 0.81 V (vs. RHE), a limiting current density of 4.95 mA cm −2 , excellent methanol tolerance, and long-term stability exceeding 92% retention after 30000 s in alkaline media. The high activity of catalyst stems from its unique structural features, including hierarchical porosity, a high degree of graphitization, and well-dispersed Co-N x active sites. These properties are achieved through the synergistic effects of nitrogen doping, cobalt stabilization, and the porous biochar framework, overcoming limitations of agglomeration and poor stability common in conventional biochar-based catalysts. The findings address key scientific challenges in enhancing ORR kinetics and stability, offering a pathway toward cost-effective and environmentally friendly alternatives to precious metal-based catalysts for energy applications.