Engineered Superhydrophilic/Superaerophobic Array Electrode Composed of NiMoO4@NiFeP for High-Performance Overall Water/Seawater Splitting

Exploring advanced electrocatalysts for overall water/seawatersplitting is significant to massive green hydrogen production. Here,we report a novel self-sacrificing template strategy to fabricatea heterostructured NiMoO4@NiFeP electrode with superwettingproperties as a bifunctional electrocatalyst for overall water/seawatersplitting. Such an electrode exhibits superior intrinsic activity,more accessible active sites, effective charge transfer, and weakadhesion of gas bubbles. Its excellent corrosion resistance and superhydrophilic/superaerophobicnanoarrayed architecture ensure its catalytic performance under harshseawater conditions. Accordingly, the electrode requires overpotentialsof only 282 and 195 mV at 100 mA cm(-2) for oxygenevolution reaction (OER) and hydrogen evolution reaction (HER) in1 M KOH seawater together with its robust durability. Operando Ramanspectroscopy together with ex situ characterization technologies revealthat NiMoO4@NiFeP was rapidly reconstructed to active Fe-doped beta-Ni oxyhydroxides (beta-Fe/NiOOH) during alkaline OER. Densityfunctional theory calculations further disclose that Fe doping canoptimize the energy barrier and modulate the d-band center of thecatalyst, intrinsically boosting the OER performance. Consequently,the NiMoO4@NiFeP-assembled electrolyzer requires a voltageof 1.71 V at 100 mA cm(-2) for seawater splittingand can stably maintain over 200 h without producing any hypochlorite.Our work holds great promise for constructing efficient non-noble-metalbifunctional electrodes toward water/seawater electrolysis applications. The heterojunction synergy and superhydrophilic/superaerophobicnanoarray structure enable the NiMoO4@NiFeP electrode tobe a high-performance bifunctional electrocatalyst for green H-2 production via water/seawater electrolysis.