Phosphorus-tungsten dual-doping boosts acidic overall seawater splitting performance over RuOx nanocrystals

Abstract

Although it is more cost-effective, producing hydrogen through acidic seawater splitting systems is still difficult, especially when it comes to creating highly effective, highly resistant chlorine corrosion bifunctional catalysts for both oxygen evolution reactions (OER) and hydrogen evolution reactions (HER). Herein, under the addition of phosphotungstic acid and the etching effect of oxalic acid, we develops a bifunctional P/W dual-doped RuOx nanocrystals for acidic overall seawater splitting, showing overpotentials of 45 and 158 mV for the HER and OER at 10 mA cm−2, respectively, and accompanying with a strong corrosion resistance towards seawater. Accordingly, the two-electrode system requires only 1.47 V to reach a current density of 10 mA cm−2 and maintains a high stability over 50 h. The P/W dual doping modulates the electrical environment of Ru sites, and the addition of oxalic acid encourages the exposure of more active sites, both of which contribute the enhancement of seawater electrolysis. Theoretical calculations further manifest the energy barriers of HER and OER can be lowered by the dual-doping. Our work offers a promising strategy to significantly increase the catalytic efficiency of Ru-based catalysts for the generation of green hydrogen from acidic seawater in a sustainable manner.