N-methylation of amines, nitro compounds and nitriles with CO2 and H2 offers a promising strategy for CO2 utilization.However, developing highly efficient and stable Cu-based catalysts for selective mono-N-methylation of aniline remains challenging.Herein, we report the successful synthesis of a Cu-ZnO/TiO2 catalyst, with the optimized 5%Cu-7.5%ZnO/TiO2 catalyst achieving a 96.7% yield of N-methylaniline (MA) and an initial turnover frequency (TOF) of 7.4 h-1 after 6 h under 453 K, 2 MPa CO2 and 4 MPa H2.This performance surpasses all reported Cu-based catalysts and rivals noble metal-based systems.The catalyst demonstrated reusability at least four cycles and versatility in the N-methylation of various amines, nitro compounds, and nitriles.Kinetic studies revealed reaction orders of 0 with respect to aniline concentration and CO2 pressure, and 1 with respect to H2 pressure.Based on kinetics and extensive characterization, we propose a reaction mechanism over 5%Cu-7.5%ZnO/TiO2, identifying Cu nanoparticles as the active sites.The process proceeds via N-phenylcarbamic acid and N-phenylformamide intermediates, with the hydrogenation of N-phenylcarbamic acid as the rate-determining step.