The invention relates to application of thiohydracrylic acid ligand modified water-soluble AIGS in photocatalytic CO2 reduction reaction, the photocatalytic CO2 reduction reaction is carried out based on the thiohydracrylic acid ligand modified water-soluble AIGS, the water-soluble AIGS adopts a Ga < 3 + >
doping strategy, and through selective substitution of Ga < 3 + > to In < 3 + > sites, lattice
defect repair and
passivation are synchronously realized, non-radiative recombination is reduced, and the photocatalytic CO2 reduction reaction is carried out on the basis of the thiohydracrylic acid ligand modified water-soluble AIGS. The AIS
quantum dot prepared by the method disclosed by the invention has the advantages that an
electron structure is regulated and controlled, the position of a
conduction band is moved to a higher position (-0.65 Vvs.NHE), the thermodynamic driving force of CO2 reduction is enhanced, and meanwhile, surface catalytic sites are optimized, so that the photocatalytic CO2
reduction activity and CH4 selectivity of the AIS
quantum dot are remarkably improved, and the overall yield is improved.