▎ 摘　　要

NOVELTY - A graphene composite is obtained by reacting 15-((methyl(methylidene)imino)methyl)-15-azatetracyclo(7.7.1.02,7.013,17)heptadeca-1,3,5,7,9(17),10,12-heptaene-14,16-dione (II) and graphene. The graphene composite has a structure (I). USE - Graphene composite e.g. thin film used for visible light absorbing photocatalyst used in regeneration of oxidoreductase cofactor e.g. nicotinamide adenine dinucleotide, nicotinamide adenine dinucleotide phosphate, flavin adenine dinucleotide and flavin mononucleotide, in enzymatic production of formic acid from carbon dioxide (all claimed). ADVANTAGE - The photocatalyst using the graphene composite enables economical and environmentally-friendly regeneration of oxidoreductase cofactor with high selectivity and reduced energy consumption, without generation of waste. The graphene composite can be mass-produced. DETAILED DESCRIPTION - A graphene composite is obtained by reacting 15-((methyl(methylidene)imino)methyl)-15-azatetracyclo(7.7.1.02,7.013,17)heptadeca-1,3,5,7,9(17),10,12-heptaene-14,16-dione of formula (II) and graphene. The graphene composite has a structure of formula (I). INDEPENDENT CLAIMS are included for the following: (1) preparation of graphene composite; (2) regeneration of oxidoreductase cofactor, which involves adding a phosphate buffer solution, oxidoreductase cofactor, methyl viologen, a ruthenium(II) complex, a rhodium(III) complex and a visible light absorbing photocatalyst containing the graphene composite to a reactor, and stirring; and (3) enzymatic production of formic acid from carbon dioxide.