▎ 摘　　要

NOVELTY - A photocatalyst composite material comprises three-dimensional porous nitrogen-doped graphitic carbon framework, raw materials containing cobalt compound, and solvent. The three-dimensional porous nitrogen-doped graphitic carbon framework is melamine, graphene, graphitized carbon, urea and/or polyvinylpyrrolidone. The cobalt-containing compound is cobalt chloride and cobalt nitrate. USE - The photocatalyst composite material is useful for preparing film used for photocatalytic reduction of carbon dioxide (claimed) into methane and carbon monoxide. ADVANTAGE - The photocatalyst composite material: can be prepared by a method, which is simple in operation, and low in cost; has unique structure and high stability; does not require heating system; and can detect carbon dioxide at room temperature with low working temperature and mild operating conditions when used for photocatalytic carbon dioxide reduction under visible light irradiation. The maximum yields of the composite material for photocatalytic reduction of carbon dioxide to methane and carbon monoxide are 10.03 micromol/(hour.g) and 5.16 micromol/(hour.g), respectively, when the composite material is exposed to visible light at room temperature of 20-30degrees Celsius. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of the photocatalyst composite material, which involves (S1) embedding cobalt nitrate into the three-dimensional porous nitrogen-doped graphitic carbon framework to make a precursor, and (S2) calcining the precursor in a tubular furnace by heating at 300-600degrees Celsius in an inert atmosphere to obtain three-dimensional porous nitrogen-doped graphitic carbon framework composite material embedded with cobalt nitrate; and (2) preparation of a photocatalytic carbon dioxide reduction film, which involves placing the photocatalyst composite material in a glass Petri dish, adding deionized water, ultrasonically dispersing the catalyst, drying the Petri dish in an oven, and evenly distributing deionized water on the surface of the dried catalyst.