Efficient oxygen reduction reaction using mesoporous Ni-doped Co₃O₄ nanowire array electrocatalysts

Herein, mesoporous Ni-doped Co₃O₄ nanowire (NW) arrays are reported as a highly efficient and low-cost catalyst for oxygen reduction reaction (ORR) in alkaline electrolyte. The Ni doping affords more electroactive sites and enhanced conductivity, and the mesoporous structure provides increased surface exposure, which may improve ion/electron transport and reduce charge transfer resistance. The NW arrays exhibit a high ORR activity with a four-electron transfer reaction in alkaline media, a half-wave potential of 0.86 V vs. RHE and a superior stability when compared to the commercial Pt (20 wt%)/C catalyst. Our results suggest that the mesoporous Ni-doped Co₃O₄ NW arrays could be a promising ORR catalyst for fuel cells and metal-air batteries.