▎ 摘　　要

NOVELTY - Preparing single-atom catalyst, comprises dissolving anhydrous aluminum chloride and polyvinylpyrrolidone in dichloromethane, adding silicon dioxide modified by vinyl triethoxysilane, adding metal-phenanthroline complex and phenanthroline, reacting, calcining precipitate to obtain core-shell material silicon dioxide-metal single-atom of nitrogen-doped graphene (M-NG), and etching nuclear layer silicon dioxide by alkali to obtain hollow spherical structure-M-NG nano-catalyst. USE - The method is useful for preparing single-atom catalyst used as photocatalyst for photocatalytic degradation of azo dyes in waste water (claimed). ADVANTAGE - The method has obvious adjustability and universality. The single atom catalyst can efficiently degrade azo dye in the waste water, and the material is pyrolyzed metal and N coordination bonding to make the metal single atom to be stably loaded on the nitrogen-doped graphene material, and has high stability. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for single-atom catalyst, prepared as mentioned above. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of a method for preparing a single-atom catalyst.