Method for preparing metal oxide or metal hydroxide nano thin-film material by molten salt method

A method for preparing a metal oxide or a metal hydroxide nano thin-film material by a molten salt method, comprising the following steps:

• heating a low-melting-point salt to a molten state, adding a substrate into the molten salt before or after melting and reaction will occur for 5 s to 1 h;
• then adding a metal source, continuing to raise a temperature or keeping the temperature unchanged, and reaction will occur for a predetermined period of time;
• removing the substrate, cooling the substrate to a room temperature, cleaning and drying the substrate to obtain metal oxide or metal hydroxide nano thin-film material;
• wherein, a mass ratio of the low-melting-point salt to the metal source is 100-1.5:1;
• the substrate is FTO conductive glass, metal titanium foil, 304 stainless steel metal, metal copper foil, nickel foam, carbon felt cloth, carbon paper or carbon fiber cloth;
• the low-melting-point salt refers to a salt with a melting point lower than 400° C., comprising nitrate, chloride, sulfate, phosphate, acetate or carbonate;
• the metal source comprises nitrate, sulfate, chloride, phosphate, titanate, tungstate, acetate, molybdate or carbonate of any one of metal elements of copper, manganese, nickel, cobalt, zinc, iron, titanium, aluminum, vanadium, chromium, molybdenum, ruthenium, tungsten, zirconium, lanthanum and cerium;
• a range of raising the temperature is between a melting point and a decomposition temperature or a boiling point of the low-melting-point salt, and the predetermined period of time is 5s to 5h.