Electrodeposited large-area nickel-alloy electrocatalysts for alkaline hydrogen evolution under industrially relevant conditions.

Developing efficient water splitting electrocatalysts plays a critical role in lowering the energy cost for hydrogen production, which requires accurate evaluation of the catalytic performance especially under industrially relevant conditions. In this work, we design a two-chamber electrolyzer testing system simulating practical water electrolyzer system to enable catalytic performance evaluation under industrially relevant conditions. A one-step electrodeposition method is used to synthesize binary and ternary Ni alloy HER catalysts and the catalytic electrodes are screened and optimized with the two-chamber electrolyzer testing system. A voltage of 1.64 V without iR compensation at a current density of 200 mA/cm2 is obtained with continuous operation for 70 h. Different HER activity trend is observed from conventional three-electrode experiments with low-concentration alkaline electrolytes at room temperature and the two-chamber electrolyzer measurements, further supporting the importance of catalytic performance evaluation under industrially relevant conditions. The electrodeposition synthesis method is further used to prepare large-area catalytic electrodes over 400 cm2 with good uniformity. • Ni-alloy HER catalysts are characterized under industrially relevant conditions with a home-build electrolyzer system. • Electrolyzer with an electrodeposited NiMo HER catalyst exhibits a remarkably low voltage of 1.64 V at 200 mA/cm2. • Different activity trends of HER catalysts are observed under industrially relevant conditions and three-electrode tests. • Ni-alloy catalysts with an active area over 400 cm2 are successfully synthesized with excellent performance uniformity. [ABSTRACT FROM AUTHOR]