A Tailored Bifunctional Electrocatalyst: Boosting Oxygen Reduction/Evolution Catalysis via Electron Transfer Between N-Doped Graphene and Perovskite Oxides

Fabricating perovskite oxide/carbon material composite catalysts is a widely accepted strategy to enhance oxygen reduction reaction/oxygen evolution reaction (ORR and OER) catalytic activities. Herein, synthesized, porous, perovskite-type Sm0.5Sr0.5CoO3-delta hollow nanofibers (SSC-HF) are hybridized with cross-linked, 3D, N-doped graphene (3DNG). This rationally designed hybrid catalyst, SSC-HF-3DNG (SSC-HG), exhibits a remarkable enhancement in ORR/OER activity in alkaline media. The synergistic effects between SSC and 3DNG during their ORR and OER processes are firstly revealed by density functional theory calculations. It suggests that electron transport from 3DNG to O-2 and SSC increases the activity of electrocatalytic reactions (ORR and OER) by activating O-2, increasing the covalent bonding of lattice oxygen. This electron transfer-accelerated catalysis behavior in SSC-HG will provide design guidelines for composites of perovskite and carbon with bifunctional catalysts.