A study was undertaken in order to investigate the potential of hydrogen (H 2 ) generation by hydrolysis of solid sodium borohydride (NaBH 4 ) with stoichiometric amount of distilled water (from molar ratios H 2 O/NaBH 4 (mol/mol) of 2 to 18), in the presence of a powder nickel-ruthenium based catalyst, reused more than 300 times. The experiments, performed in batch reactors with different free volumes and bottom shapes (flat and conical) reveal – for the conical bottom shape with any excess of water – 8.1 H 2 wt% and 92 kg H 2 /m 3 (materials-only basis), and a H 2 rate of 87.4 L(H 2 ) min −1 g −1 catalyst, at the moderate pressure of ∼1.2 MPa. The results presented in this work give emphasis to the importance of considering the role of reactor bottom geometry on the solid NaBH 4 hydrolysis studies performed with stoichiometric amounts of liquid water.