Porous biomass-derived carbon modified by Cu, N co-doping and Cu nanoparticles as high-efficient electrocatalyst for oxygen reduction reaction and zinc-air battery

Exploration of new non-precious metal catalysts for highly efficient oxygen reduction reaction (ORR) is essential for sustainable energy utilization technologies. Herein, porous biomass-derived carbon modified by Cu, N co-doping and Cu nanoparticles was synthesized by hydrothermal followed pyrolysis strategy, and used for electrocatalytic ORR. The optimized Cu/Cu-N-C catalyst exhibits large surface area (235.91 cm3 g−1) and hierarchical pore structure. Benefiting from the above factors, the Cu/Cu-N-C catalyst performs a high onset potential (Eonset, 0.947 V vs. reversible hydrogen potential (RHE)) and a half-wave potential (E1/2, 0.875 V vs. RHE) in 0.1 M KOH solution. The calculated electron transfer number of 3.92 suggests the near-four-electron ORR process. Besides, the Cu/Cu-N-C catalyst also performs extraordinary stability and higher methanol tolerance than Pt/C. In addition, the assembled Zn-air battery based on the optimized Cu/Cu-N-C catalyst exhibits a higher power density of 150.7 mW cm−2 than the that of Pt/C-based battery. This work put forward a newfangled method to fabricate efficient ORR catalyst by loading active component on biomass-derived carbon, which follows the sustainable development concept, and provides a profitable reference for designing nonprecious metal carbon-based ORR electrocatalyst.