CoB supported on Ag-activated TiO sub(2) as a highly active catalyst for hydrolysis of alkaline NaBH sub(4) solution

In this study, a series of TiO sub(2) (activated by Ag) supported CoB catalysts were synthesized using electroless deposition method. Compared to the unsupported CoB catalyst, the CoB/Ag-TiO sub(2) catalysts showed much better catalytic activity and higher stability on hydrolysis of NaBH sub(4) in alkaline aqueous solution and the catalysts were insensitive to air oxidation. The optimistic loading amount of CoB was 2.8 wt% and its hydrogen generation rate reached 6294 mL min super(-1) (g Co) super(-1) in 1 wt% NaBH sub(4) + 5 wt% NaOH solution at 293 K. The catalytic activity was comparable to some noble catalysts and could retain nearly 70% after 5 cycles. The catalysts were studied by varies techniques and the results revealed that the dispersion of CoB was improved and the CoB/Ag-TiO sub(2) catalysts possessed distinct porous structure which could promote the diffusion of reactants/products. The surface composition and the electron transfer effects between the Co super(0) with B super(0) and Ag super(0) could also affect the catalytic activity. Under the current experimental conditions, the specific activation energy of 2.8CoB/Ag-TiO sub(2) catalyst was determined as 44 kJ mol super(-1) and the kinetic equation was also deduced.