High electrocatalytic activity of Rh-WO3 electrocatalyst for hydrogen evolution reaction under the acidic, alkaline, and alkaline-seawater electrolytes

One potential strategy to develop hydrogen evolution electrocatalysts for producing sustainable hydrogen in water electrolysis is creating electrocatalysts with low-cost, high activity, and high stability. Herein, we show that low-loading metal-based tungsten oxide (WO3) can be used as electrocatalysts for the hydrogen evolution reaction (HER) in acid, alkaline, and alkaline-seawater electrolytes. Among prepared electrocatalysts, rhodium (Rh)-WO3 exhibits a high HER activity with the values of overpotential of 48, 116, and 98 mV to obtain a current density of 10 mA cm−2 in acid, alkaline, and alkaline-seawater electrolytes, respectively. In addition, the Rh-WO3 electrocatalyst shows high stability during the HER operation for over 60,000 s. Besides, the application of Rh-WO3 electrocatalyst as cathode and commercial ruthenium oxide (RuO2) as an anode for overall water splitting show excellent efficiency with only a potential of 1.45 V to a current density of 10 mA cm−2 in the alkaline-seawater electrolyte. The Rh-WO3//RuO2 cell also exhibits high stability for over 80,000 s and maintains a current of 15 mA cm2 at a cell voltage of 1.51 V. The results provide evidence that Rh-WO3 can be a promising HER catalyst for sustainable hydrogen production via alkaline-seawater electrolysis application.