Enhancing Bifunctional Catalytic Activity of Oxygen Reduction and Evolution Reaction via One-Pot Formation of MnO2-Carbon Hybrid Nanocomposite

摘要

While manganese dioxide (MnO2) is a promising bifunctional electrocatalyst for oxygen reduction and evolution reaction (ORR/OER) in alkaline media, electrochemical performance of bulk MnO2 limited by their poor electrical conductivity. Herein, we fabricate a MnO2-carbon nanoparticle hybrid composite (MO-CNP) by applying the plasma discharge in the single precursor of purple benzene. This synthesis route facilitates a simultaneous formation of MnO2 and carbon, which induced a homogeneously mixed and firmly anchored hybrid composite. As a result, as-obtained MO-CNP-1 shows more than 12 times higher electrical conductivity than that of prepared conventionally. Thus, formation of MO-CNP could be accompanied by a synergy between MnO2 and CNP as electrocatalyst, and consequently, electrochemical properties were significantly improved. In comparison with CNP, the ORR potential of MO-CNP-1 was positively shifted from -0.28 to -0.23 V (vs. Ag/ AgCI), and current density has increased more than 2 times. Although the ORR activity of MO-CNP-1 was still far a little short of the commercial Pt/C, the MO-CNP-1 indicated significant higher OER activity, which demonstrated excellent overall catalytic capability of MO-CNP-1 as bifunctional catalyst.