Fast hydrolysis and hydrogen generation on Al-Bi alloys and Al-Bi-C composites synthesized by high-pressure torsion

Al-Bi alloys and Al-Bi-C composites with different compositions were synthesized by high-pressure torsion (HPT) and their hydrogen generation behavior via hydrolysis was investigated in contact with pure water. Bi was added to Al to enhance the effect of nano-galvanic cells and to promote the pitting corrosion, and C in the form of graphite was added to Al to accelerate the fragmentation of the composite and to increase the total active surface area. An optimized Al-30 wt%Bi-10 wt%C composition exhibited a hydrogen generation rate as fast as 270 ml min−1 g−1 in water and its total hydrogen generation amount reached the theoretical level at 333 K (all aluminum atoms reacted with water in less than 10 min and formed Al2O3).