▎ 摘　　要

NOVELTY - Preparing composite nanomaterial comprises dispersing the two-dimensional nano-sheet in the first organic solvent to prepare the dispersion liquid, and dissolving the organic platinum salt and other transition metal salt in the first organic solvent to prepare mixed salt solution; mixing the mixed salt solution with the dispersion according to a specified molar ratio; reacting the mixed solution under the protective gas atmosphere at a preset reaction temperature to obtain the composite nanomaterial. USE - The method is useful for preparing composite nanomaterial, which is useful as catalyst for producing hydrogen by electrolysis of water (all claimed). ADVANTAGE - The method facilitates promotion of the chemical adsorption and activation of composite nanomaterial reactants, can improve the catalytic performance of a hydrogen production reaction, thus improving the hydrogen production efficiency to reduce the energy consumption. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a composite nanomaterial; and (2) a catalyst for the production of hydrogen by electrolysis of water comprising the composite nanomaterial.