Ultrastable and highly efficient hydrogen evolution by heterogeneous NiO/Ni catalysts under industrial electrolysis conditions

The kinetics of charge transfer in high-current-driven alkaline water splitting is generally slow, limiting large-scale hydrogen production. Developing non-precious metal catalysts with high activity and stability remains a challenge. We've electrodeposited a starfruit-shaped NiO/Ni layer in situ on copper foam, demonstrating excellent electrocatalytic activity and stability for industrial alkaline hydrogen evolution. The high catalytic activity can be attributed to fast electron and mass transport, excellent intrinsic activity, and superhydrophilicity. Consequently, the NiO/Ni@Cu catalyst exhibits high hydrogen evolution reaction (HER) performance with overpotentials of 72 and 146 mV at 100 and 500 mA cm-2, respectively, and a Tafel slope of 29.2 mV dec-1. Meanwhile, this good HER catalyst also works well in water electrolysis with an ultra-low voltage of 1.47 V@100 mA cm-2 and demonstrates remarkable durability during operation for 200 h at 80 degrees C in 6 M KOH. More importantly, this efficient electrolyzer delivers the industrially relevant current density of 500 mA cm-2 at a voltage of 1.54 V, which is 13 times higher than that delivered by RuO2||Pt/C and three orders of magnitude higher than that delivered by NF||NiFe LDH. This work provides a simple and rapid technique for building high-performance, low-cost, industrially available electrodes for an efficient alkaline HER. The heterojunction of NiO/Ni synergistically optimizes the kinetics during the alkaline hydrogen evolution process, thereby enhancing the catalytic performance beyond that of Pt/C.