Graphene oxide has been widely modified and used in carbon dioxide reduction reactions (CO2RR). Research suggests that using activated carbon with graphene oxide enhances surface wetness, improving its adsorption and capacitance capabilities to boost CO2RR catalytic activity. Moreover, the usage and doping of inorganic chemicals such as graphene oxide are complicated and require a high doping temperature. In this work, a one-pot synthesis technique was used in producing activated carbon-graphene oxide composite in-situ with polyethyleneimine-functionalized supported copper nanoparticles. Linking and hybridization using polyethyleneimine solution at 45 °C successfully improved pyrrolic and quaternary N by 13.23. It is further supported by presence of carboxyl group (CdbndO) and other oxygenated functional groups up to 16.75%, beneficial for the electrode's catalytic activity. The electrochemical tests (Linear Sweep Voltammetry, Cyclic Voltammetry, and Chronoamperometry) showed that the AC-PEI-GO-Cu electrode has higher current density than the raw material (20 mA/cm2 vs. 5.5 mA/cm2 at �1.2 V applied potential) and improved reaction kinetics, where Tafel slope value decreased from 0.990 to 0.318 mV/dec. It produced a high current density due to the addition of heteroatoms such as N and O and presence of Cu catalyst, which led to different pore diameters. Limited work on AC-GO materials in the field of CO2RR justifies the significance of this present work. © 2022