At present, the chemical activation method is used to prepare activated carbon from poplar sawdust. Co/activated carbon (Co/AC) is synthesized by the sodium borohydride (SBH, NaBH4) reduction method. The catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy-X-ray energy dispersion (SEM-EDX) analytical techniques. The catalytic activity, stability, and resistance of the Co/AC catalysts are determined by electrochemical analyses such as cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS), respectively. The 1 % Co/AC catalyst exhibits the highest catalytic activity at a specific activity of 3.964 mA/cm2 compared to other catalysts. Furthermore, it has shown long-term stability and low resistance. The effect of the catalyst, sodium borohydride and methanol amounts, and temperature parameters on the initial hydrogen generation rate are determined. The initial hydrogen generation rate of the 1 % Co/AC catalyst is obtained as 26053.2 mL/min.gcat at optimum parameters such as 0.025 g catalyst, 0.15 g NaBH4, 6 mL methanol, and 60 °C temperature. As a result, 1 % Co/AC catalyst is promising both as an anode electrode material and catalyst for sodium borohydride methanolysis. •The activated carbon (AC) is prepared by the chemical activation method with phosphoric acid (H3PO4) of poplar sawdust.•AC-supported Co catalysts are successfully synthesized by the NaBH4 reduction method.•The characterization results reveal that the desired structure has been formed.•Co/AC catalyst exhibits the highest catalytic activity (3.964 mA/cm2) and the initial HGR (26053.2 mL/min.gcat).