Constructing MoPx@MnPy Heteronanoparticle-Supported Mesoporous N,P-Codoped Graphene for Boosting Oxygen Reduction and Oxygen Evolution Reaction

Developing efficient and cost-effective bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly important for fabricating energy conversion and storage technologies, such as fuel cells, water electrolyzers, and metal air batteries. Herein, we report a facile and economical route for synthesizing ultrasmall molybdenum phosphide (MoPy) nanocrystal-attached mesoporous manganese phosphides on N,P-codoped graphene nanosheets, which display equivalent ORR (OER) activity to that of Pt/C (RuO2) catalysts. This is manifested by the positive onset potential (0.969 V) and half-wave potential (0.842 V) for ORR, as well as a mere overpotential of 301 mV at a current density of 20 mA-cm(-2) and a small Tafel slope of 105 mV.dec(-1) for OER in alkaline medium. It also demonstrates remarkable stability in comparison with Pt/C and RuO2 for both ORR and OER, respectively. The excellent performance can be attributed to the mesoporous structure with enhanced multiple types of electroactive sites, which highly favors the adsorption and catalyzation of reactants, as well as efficient reagent/product mass transport. The findings can pave a new way for the synthesis and usage of a hybrid as a bifunctional catalyst with high efficiency and outstanding longevity to enable next generation of energy conversion and storage.