  Large scale production of hydrogen by electrochemical water splitting is
considered as a promising technology to address critical energy challenges
caused by the extensive use of fossil fuels. Although nonprecious nickel-based
catalysts work well at low current densities, they need large overpotentials at
high current densities that hinders their potential applications in practical
industry. Here we report a hydroxide-mediated nickel based electrocatalyst for
high current density hydrogen evolution, which delivers a current density of
1000 mA cm-2 at an overpotential of 98 mV. Combined X-ray absorption
spectroscopy and high resolution X-ray photoelectron spectroscopy results show
charge redistribution of nickel sites caused by Mo and surface FeOx clusters,
which can stabilize the surface nickel hydroxide at high current densities for
promoting water dissociation step. Such catalyst is synthesized at the metre
scale and shows a current density of 500 mA cm-2 at 1.56 V in the overall water
splitting, which demonstrate its potential for practical use. This work
highlights a charge-engineering strategy for rational design of catalysts that
work well at high current densities.
