The coralline cobalt oxides compound of multiple valence states deriving from flower-like layered double hydroxide for efficient hydrogen generation from hydrolysis of NaBH4

Efficient hydrogen storage, transportation and generation are key-technology for future hydrogen economy . Sodium borohydride (NaBH 4 ) stands out as promising hydrogen energy carrier with merits of high volumetric density and environmentally benign hydrolysis products. Flower-like layered double hydroxide α-Co(OH) 2 with intercalation of B species was synthesized via hydrothermal crystallization method using sodium tetraphenylboron as source of B and alkaline, which makes it different from the previous supporting materials. Pure or mixed cobalt oxides with different valence states containing B (CoO/B, Co 3 O 4 /B, Co+CoO/B, CoO+Co 3 O 4 /B) were subtly prepared via controlling calcination temperature, time and atmosphere for sodium borohydride hydrolysis. Coral-like CoO+Co 3 O 4 /B displayed superior hydrogen generation rate (6478 ml H2 ·min −1 ·g −1 metal ) with arrhenius activation energies of 41.14 kJ/mol for NaBH 4 hydrolysis in alkaline solutions compared to those reported pure precious metals. The out-standing catalytic performance of CoO+Co 3 O 4 /B may be attributed to electron transfer among cobalt oxide. DFT calculation indicates NaBH 4 hydrolysis undergoes a reaction path on CoO+Co 3 O 4 surface with lower relative energies.