Synergistic Effects of C/alpha-MoC and Ag for Efficient Oxygen Reduction Reaction

It remains challenging to prepare highly active and stable catalysts from earth-abundant elements for the oxygen reduction reaction (ORR). Herein we report a facile method to synthesize cost-effective heterogeneous C/alpha-MoC/Ag electrocatalysts. Rotating disc electrode (RDE) experiments revealed that the obtained C/alpha-MoC/Ag exhibited much superior catalytic performance for ORR than that of C/Ag, C/alpha-MoC, or even the conventional Pt/C. First-principles calculations indicated that the enhanced activity could be attributed to the efficient synergistic effects between Ag and alpha-MoC/C by which the energy barrier for O-2 dissociation has been substantially reduced. Furthermore, Li-air and Al-air cells were assembled to demonstrate the unprecedented electrochemical performance of C/alpha-MoC/Ag nanocomposites surpassing the Pt/C. Thus experimental results and theoretical calculations together showed that the heterogeneous C/alpha-MoC/Ag nanocomposites are a promising alternative to platinum for applications in industrial metal-air batteries.