Trace cobalt accelerates the structural reconstruction to generate high-valence nickel for water-splitting in seawater media

Key Words:ENHANCED HYDROGEN EVOLUTION; OXYGEN; EFFICIENT; NANOPARTICLES; ELECTRODE; OXIDES; METAL

Abstract:To boost the full utilization of water electrolysis for energy conversion and storage, it is urgent to develop nonnoble metal-based electrocatalysts with exceptional activity and stability. Herein, a combination of corrosion engineering and subsequent phosphorization processes is employed to prepare nickel iron foam (NIF)-supported cobalt/iron/nickel-based metal oxides (Co-NiFeOx/NIF) and metal phosphides (Co-NiFeP/NIF) with superhydrophilic and superaerophobic nanosheet morphology. The superhydrophilic and superaerophobic structure ensures optimal contact with the electrolyte and facilitates the rapid release of gas bubbles during electrocatalysis. Notably, the presence of Co optimizes the oxidation state of Ni, facilitating the formation of Ni3+ active sites, thereby improving the oxygen evolution reaction (OER) performance and enhancing the overall catalytic activity. Consequently, the designed Co-NiFeOx/NIF catalyst achieves low overpotentials of 223/240 mV @10 mA cm-2 in alkaline freshwater and seawater for OER. Specially, the optimal Co-NiFeP/NIF||Co-NiFeOx/NIF electrolyzer requires only 1.56 and 1.60 V to deliver 10 mA cm-2 for alkaline freshwater/seawater splitting. The work aims to promote the widespread application of renewable energy sources by developing efficient and costeffective non-precious metal catalysts.

Volume:515

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Translation or Not:no