Abstract Mesoporous Co–B with worm-like morphology was firstly prepared via reduction of cobalt acetate by potassium borohydride in the presence of triblock copolymer templates. The as-prepared mesoporous Co–B was characterized by Fourier transform infrared (FTIR), X-ray powder diffraction (XRD), transmission electron microscopy (TEM), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), and N 2 adsorption–desorption. During the hydrolysis of KBH 4, the mesoporous Co–B exhibited much higher catalytic activity than the regular Co–B. It is attributed to the larger specific surface area (163.77 m 2/g) and mesoporous channels. The average H 2 generation rate of the mesoporous Co–B was 3523 mL/min g catalyst in 1.3 wt% NaOH + 13 wt.% KBH 4 solution at 286 K, which may give a successive H 2 supply for a 571 W polymer electrolyte membrane fuel cell (PEMFC) at 100% H 2 utilization. Furthermore, the as-prepared mesoporous Co–B with high specific surface area is expected to find applications in many catalytic hydrogenation reactions.