Porous Co-B nanoalloy is a low-cost and highly active catalyst towards the hydrolysis of sodium borohydride (NaBH4). In this study, a facile and room-temperature hydrogen bubble-assisted method was developed to prepare porous Co-B nanoalloy (CO-B-bubble) materials exhibiting high catalytic activity. The obtained materials are characterized by Xray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometer, transmission electron microscopy and surface area experiments. It is found that the hydrogen bubbles generated in-situ in the reaction system can act as template, which played an important role in determining the porous architecture of the final Co-B product. In the hydrolysis of sodium borohydride for hydrogen generation, the porous CO B-bubble nanoalloy materials exhibit high catalytic activity with mass normalized rate constant of 5.31 L-hydrogen min(-1) g(catalyst)(-1): a value which is much higher than those obtained for many other Co-B catalysts recently reported in the literature. The apparent activation energy (Ea) of the catalytic process is found to be ca. 30 kJ mol(-1). It is proposed that the high catalytic performance and low cost of Co-B(bubble )nanoalloy catalyst can be a promising material candidate in the hydrolysis of sodium borohydride for hydrogen production for commercial applications. (C) 2018 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC.