Shape-selective fabrication of Cu nanostructures: Contrastive study of catalytic ability for hydrolytically releasing H2 from ammonia borane

Ammonia borane, a promising hydrogen store material with the highest H capacity (19.6%), can controllably release H2 gas via suitable catalysis, which thus necessitates search for effective and inexpensive catalysts. We herein report a highly shape-selective fabrication strategy for Cu nanocrystals with the specially-designed nanostructures (nanocube, nanowire and nanotetrahedron, etc) via the same solution reduction route by simply adjusting addition proportion of the reductant and orientation agent. Contrastive studies of the Cu nanocrystals for catalytically hydrolyzing ammonia borane to release H2 amply demonstrate the obviously close correlativity between catalytic ability and the morphologies. In comparison to the ordinary Cu nanoparticles with extremely low or hardly any dehydrogenation activity, all of the regularly-shaped Cu nanocrystals hold the unexpectedly robust catalytic activity, in which the nano-cubed Cu nanocrystals possess the highest catalytic activity almost equivalent to some noble metals, followed by the nanotetrahedrons and nanowires. In theory, the well-designed shape tuning tactics could provide reference for fabricating highly active nano/micro catalysts concerning other metal systems.