Hydrogen generation from water and aluminum promoted by sodium stannate

A new process to obtain H 2 from H 2O using Al corrosion in Na 2SnO 3 solutions is described. Results showed an enhancement of H 2 production rates using Na 2SnO 3 instead of NaOH at the same pH. A side reaction of Al in Na 2SnO 3 solutions has been found, which consumes Al to produce metallic Sn. H 2 yield depends chiefly on Al/Na 2SnO 3 molar ratio for experiments with Na 2SnO 3 concentrations above 0.025 M, reaching higher yields with higher Al/Na 2SnO 3 ratios. The maximum H 2 production rates are proportional to the initially added Al mass. Two different shrinking core models for examining the kinetics of H 2 generation are verified and the activation energy ( E a ) is 73 ± 6 kJ mol −1, confirming a rate control by a chemical step. A mechanism of Al corrosion in Na 2SnO 3 solutions is proposed and compared with the mechanism in NaOH and NaAlO 2 solutions.