▎ 摘　　要

NOVELTY - Nano-material comprises graphene and a metal nitrogen dopant supported by graphene oxide, where the metal nitrogen dopant is formed from a metal precursor and a nitrogen precursor, and the metal precursor comprises iron salt, cobalt salt and/or nickel salt. USE - The nano-material is used as catalyst in photo-catalytic reaction and/or used for preparing photodynamic therapeutic agent (claimed). ADVANTAGE - The nano-material is used as catalyst to improve photo-catalytic activity. The method is simple, and ensures reduced production cost and excellent reproducibility. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the nano-material, involving (a) preparing the metal precursor into solution to obtain a metal ion solution, (b) adding the oxidized graphene to water to obtain a graphene dispersion, (c) adding the metal ion solution, nitrogen precursor to the graphene dispersion, uniformly stirring, freezing and drying to obtain a freeze-dried mixture, (d) performing the first annealing treatment to the freeze-dried mixture, and (e) performing the second annealing treatment to the freeze-dried mixture to obtain the product.