摘要： The photocatalytic H2 evolution is an important technology to solve the energy crisis. The hydrogen evolution rate of the g-C3N4 system in triethanolamine solution as sacrificial agent is obvious higher than in methanol solution. But up to now, most of the Cu nanoparticles as cocatalyst of g-C3N4 photocatalytic systems for hydrogen evolution are performed in methanol solution because Cu nanoparticles are unstable in triethanolamine solution. Here, carbon coated-Cu nanoparticles as cocatalyst of g-C3N4 composites (Cu@C/g-C3N4) were prepared by simple two-steps technology of annealing then grinding. The compositions, morphology and optical and photoelectrochemical (PEC) properties of the composites were characterized by means of physicochemical techniques. The prepared composition was used to generate hydrogen under visible light irradiation in triethanolamine solution. The results displayed that the hydrogen evolution rate of the optimal Cu@C/g-C3N4 was up to 265.1 μmol g-1 h-1 that is close to the activity of 0.5% Pt/g-C3N4, and after four repeated reactions, the photocatalytic activity decreased only by about 15%. The good photocatalytic activity and stability result from Cu nanoparticles increase the transfer efficiency of charge carriers by trapping the photogenerated electrons produced by g-C3N4 and the protective effect of carbon layer on Cu nanoparticles.