2013 年 38 巻 3 号 p. 459-462
Hollow nickel-silica composite spheres were synthesized by sol-gel based method using L(+)-arginine as a promoter for the reaction followed by in-situ activation in aqueous sodium borohydride (NaBH4)/ammonia borane (NH3BH3) solutions. The resulting powder products include hollow spheres with the diameters of 200-400 nm and wall thickness of ca. 60 nm. The evolution of 2, 53, and 58 mL hydrogen was finished in about 25, 310, and 90 min in the presence of the hollow nickel-silica composite spheres from aqueous NH3BH3 solution, aqueous NH3BH3 solution following by ex-situ activation in aqueous NaBH4 solution, and aqueous NaBH4/NH3BH3 solution, respectively. The results indicate that the in-situ synthesized hollow nickel-silica composite spheres in aqueous NaBH4/NH3BH3 solution show higher activity for hydrolytic dehydrogenation of NH3BH3 than the hollow nickel-silica composite spheres obtained in aqueous NH3BH3 solution and in aqueous NH3BH3 solution following ex-situ activation in aqueous NaBH4 solution. The evolution of 50 mL hydrogen was finished in about 100 min introducing additional aqueous NH3BH3 solution to the solution in the presence of the in-situ synthesized hollow nickel-silica composite spheres, indicating the in-situ synthesized hollow nickel-silica composite spheres have the ability for recycle use for hydrolytic dehydrogenation of NH3BH3.
