W-modified CoB supported on Ag-activated TiO2 for hydrogen generation from alkaline NaBH4 solution

A one-step electroless plating method was applied to synthesize a series of TiO2 (activated by Ag) supported W modified CoB catalysts for H-2 generation from hydrolysis of NaBH4. The modification amount of W was optimized and the highest H-2 generation rate reached 7.27 L min(-1) (g Co)(-1) in 1 wt% NaBH4 solution (with 5 wt% NaOH as stabilizer) at 293 K, nearly 16% improvement over the undoped 3CoB/Ag-TiO2 catalyst. The catalytic activity was comparable with some noble metal catalysts. The catalyst could retain similar to 50% of initial activity after 5 runs and was stable in ambient air. Further characterizations revealed that the high dispersion of W-CoB, the distinct mesoporous structure inherited from TiO2 support and the electron interactions among Co degrees, B degrees and W degrees might account for the high performance. The tungsten oxide existed on the surface of catalysts could act as Lewis acid to facilitate the adsorption of BH4- ions, which would further enhance the catalytic performance. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.