Commercial anion exchange membrane water electrolyzer stack through non-precious metal electrocatalysts

The activity and durability of the electrolyzer stack system is demonstrated by applying a partially oxidized nano-particle. • Partially oxidized NiCo (NiCoO-NiCo/C) electrocatalyst exhibited high activity and durability for HER. • NiCoO-NiCo/C electrocatalyst as cathode improved the performance of single-cell AEMWE. • 5-cell stack AEMWE applied by NiCoO-NiCo/C electrocatalyst showed high performance. Ni-based electrocatalysts for replacement of precious metal electrocatalyst, the cathode materials of anion exchange membrane water electrolyzer (AEMWE), are seriously unstable and low activity at hydrogen production conditions. This study develops a high-performance, durable non-precious metal electrocatalyst for AEMWE, which show improved activity and durability. First, Ni/C was alloyed with Co and supported on carbon cloth coated with microporous carbon layer to improve the electrocatalytic activity of the hydrogen evolution reaction (HER) electrocatalyst; then, oxide (Ni/Co-O) was locally formed on the synthesized NiCo/C to increase its activity and durability. Specifically, this oxide increased the coverage of OH − ions, formed hydrogen spillover channels, and promoted the HER. Further, its improved electrochemical durability was attributed to the high bond dissociation energy of the metal oxide. The electrocatalyst was also evaluated as the cathode in single-cell (1-cell) and stack cell (5-cell) AEMWE systems to demonstrate that this superior performance would translate to the commercial scale.