Thermal Shock-Activated Spontaneous Growing of Nanosheets for Overall Water Splitting

Nanomaterials based on nickel foam (NF) have been widely applied in energy conversion and storage field. Traditional synthesis methods such as hydrothermal method which is dangerous and high cost limited the scalable developments. Herein, we report a fast, simple, and low-cost synthesis method of nanomaterials based on NF by Joule-heating and water soaking treatment. Thin carbon-coated CoS on NF (NF-C/CoS) was synthesized by Joule-heating for a few seconds with rapid cooling. And then, NF-C/CoS/NiOOH with core–shell heterostructure was fabricated by soaking treatment of NF-C/CoS in water on which NiOOH nanosheets grew spontaneously. The formation mechanism is proposed that the coordination complex precursor converts into C/CoS on NF driven by Joule-heating, and the nickel on the surface of NF is activated to form metastable nickel simultaneously. The metastable nickel reacting with water leads to the formation of NiOOH, and the induction of CoS makes NiOOH grow continuously. This synthesis technology provides a new route to manufacture NF-based nanostructures, and the as-fabricated NF-C/CoS/NiOOH exhibits great potential as electrocatalyst for oxygen evolution reaction and hydrogen evolution reaction.