Zero emission become the global issue, and the production of hydrogen fr
om green energy is emerging. Green hydrogen is mainly produced by the
electrolysis of water using renewable energy. The difficulty of hydrogen pr
oduction through electrocatalytic water splitting lies in the unstable opera
tion under high currents and the high cost of the electrocatalysts. Our tea

m developed an acidic redox-assisted deposition (ARD) method to roll-to-
roll synthesize low-cost multimetal oxide films at room temperature, and t

he products used as oxygen evolution reaction (OER) or hydrogen evoluti
on reaction (HER) catalysts for alkaline seawater splitting. We have develo
ped a low-cost method to produce high adhesion –thin-film catalysts und
er high current against bubbling of gases that achieving H2 production eff
iciency of 71% (at 80 oC) at a current density of 1000 mA cm-2, correspon
ding to about 4.2 kWh N-1 m-3 and sustains stable operation for more th
an 720 hours in electrolyzer operation (using anion-exchange membrane,
AEM), and the catalyst is stable for at least 5 hours at 0.4A/cm2 in the sea
water.