Dual-doping NiMoO4 with multi-channel structure enable urea-assisted energy-saving H2 production at large current density in alkaline seawater

Seawater electrolysis is an efficient method for producing carbon-neutral hydrogen; however, it is hindered by high energy cost and chlorine evolution reaction. In this study, we report Ru, P dual-doped NiMoO4 multichannel nanorods in-situ grown on nickel foam (Ru/P-NiMoO4 @NF), which can achieve chlorine-free hydrogen production by coupling seawater splitting with thermodynamically favorable urea oxidation. The Ru/P-NiMoO4 @NF exhibits bifunctional activity with working potentials of 0.23 V to deliver 3000 mA cm-2 for HER and 1.46 V to deliver 1000 mA cm-2 for UOR. The overall urea splitting system in the two-electrode electrolyzer require low voltage of 1.73 V to drive 500 mA cm-2, and demonstrate remarkable durability to keep above 100 mA cm-2 for 145 h. Density functional theory calculations reveal that dual-doping modulate the D-band center of catalyst, thus enhancing the adsorption of reactants and intermediates. This work provides information for designing catalysts for combing seawater splitting with urea purification.

Automated summary

In this study, Ru, P dual-doped NiMoO4 multichannel nanorods in-situ grown on nickel foam (Ru/P-NiMoO4@NF) are reported, which can achieve chlorine-free hydrogen production by coupling seawater splitting with thermodynamically favorable urea oxidation. The Ru/P-NiMoO4@NF exhibits bifunctional activity and shows good durability and low driving voltage requirements.