An enhanced non-noble perovskite-based oxygen electrocatalyst for efficient oxygen reduction and evolution reactions

Developing cost-effective and efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of considerable importance for fuel cells and metal-air batteries. In this work, a non-precious composite (i.e., Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF), g-C3N4 and Vulcan carbon (VC)) labeled as BSCF/g-C3N4-VC was developed via ultrasonically mixing. The formed BSCF/g-C3N4-VC exhibited improved ORR and OER activity compared with the individual g-C3N4 and BSCF, as well as the composites of g-C3N4-VC and BSCF/VC. The critical roles of BSCF, g-C3N4, and VC for boosting ORR and OER have been clearly demonstrated. Apparently, the prepared composite overcame major limitations of perovskite-type BSCF and g-C3N4, i.e., the relatively low specific surface area (similar to 0.27 m(2) g(-1)) of the former and the extremely low electronic conductivity of the latter. Moreover, the significantly enhanced electrocatalytic activity could be attributed to the synergistic effect between g-C3N4, BSCF, and VC. Our results suggest that facilely compositing carbon materials (e.g. VC and g-C3N4) with perovskite-type oxides (e.g. BSCF) will open a new path for the development of highly efficient oxygen electrocatalysts.