CoMoN-An efficient multifunctional electrocatalyst.

Efficient catalysts are required for both oxidative and reductive reactions of hydrogen and oxygen in sustainable energy conversion devices. However, current precious metal-based electrocatalysts do not perform well across the full range of reactions and reported multifunctional catalysts are all complex hybrids. Here, we show that single-phase porous CoMoN prepared via a facile method is an efficient and reliable electrocatalyst for three essential energy conversion reactions; oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) in alkaline solutions. CoMoN presents outstanding OER, ORR, and HER activity with high durability, comparable with the commercial catalysts RuO for OER and Pt/C for ORR and HER. In practical demonstrations, CoMoN gives high specific capacity (850 mA h g at 10 mA cm) as the cathode in a zinc-air battery, and a low potential (1.63 V at 10 mA cm) used in a water-splitting electrolyzer. Availability of Co and Mo d-states appear to result in high ORR and HER performance, while the OER properties result from a cobalt oxide-rich activation surface layer. Our findings will inspire further development of bimetallic nitrides as cost-effective and versatile multifunctional catalysts that will enable scalable usage of electrochemical energy devices.