Prussian blue analogues-derived carbon composite with cobalt nanoparticles as an efficient bifunctional electrocatalyst for oxygen reduction and hydrogen evolution

Abstract

Oxygen reduction reaction and hydrogen evolution reaction are two key reactions involved in several renewable energy technologies. Herein, a nonprecious bifunctional electrocatalyst for oxygen reduction reaction and hydrogen evolution reaction is facilely synthesized through directly pyrolyzing the mixture of Prussian blue analogues, graphene oxide and graphitic carbon nitride in the presence of silica colloids. Post-synthesis removal of silica hard templates leads to a cobalt and nitrogen co-doped reduced graphene oxide composite with Co nanoparticles, which comprises abundant mesoporous textures and a high specific surface area of 703.26 cm2 g−1. The resultant composite shows marked oxygen reduction reaction activity, with a more positive half-wave potential of +0.848 V, a higher limiting current, a stronger immunity to fuel crossover effect and higher operation stability, as compared with commercial Pt/C catalyst in alkaline solution. Besides, such composite can also serve as efficient and stable hydrogen evolution reaction catalyst in alkaline electrolyte, and an overpotential of only 180 mV is required to reach 10 mA cm−2. The remarkable bifunctional catalytic activities are attributed to the synergistic effects of Co nanoparticles and graphene substrate. These results highlight the high potential of present strategy in synthesis of multifunctional nonprecious electrocatalysts.