Insights into the Catalytic Activity of Barium Carbonate for Oxygen Reduction Reaction

Efficient electrocatalyst for oxygen reduction reaction (ORR) is crucial for the performance improvement of fuel cells and metal-air batteries. However, catalyst with high activity, easy fabrication process, and low cost is still a daunting challenge. In this work, low-cost BaCO3 nanorods have been demonstrated as efficient electrocatalysts toward the ORR in alkaline media for the first time. The activity of BaCO3 nanorods can be further enhanced by hybridizing with reduced graphene oxide (BaCO3/rGO). The mechanism of ORR on the surface of BaCO3 catalyst was investigated via in situ electrochemical Raman spectroscopy (in situ EC-Raman). Our findings suggest that the barium ions on the surface of catalyst play a key role in the adsorption of oxygen molecules and the formation/decomposition of intermediates. This work provides an important insight into the catalytic activity of BaCO3 for ORR, which can serve as a guide for the design of alkali-earth metal-carbonate-based catalyst.