The electrochemical CO 2 reduction reaction (CO 2 RR) is a promising approach to upgrading CO 2 into methane (CH 4 ) and other high-value-added chemicals, critical for lowering carbon emissions and mitigating the greenhouse effect. However, the selectivity of CO 2 RR to methane remains low at the current densities required for commercialization. Herein, we report a simple one-step synthesis of monodisperse copper-based catalysts for efficient electromethanation of CO 2 . Through rational regulation of active sites, the selectivity for methane production can reach as high as 57.02% under the current density of 300 mA cm −2 as a result of suppressed C−C coupling for improved *CO hydrogenation. This work offers an effective strategy to regulate Cu-based catalysts to manage the hydrogenation of *CO for CO 2 RR toward CH 4 formation.