The effect of the pore structures of hollow silica–alumina composite spheres on their activity for the hydrolytic dehydrogenation of ammonia borane has been studied.Following a calcination process that resulted in ho...The effect of the pore structures of hollow silica–alumina composite spheres on their activity for the hydrolytic dehydrogenation of ammonia borane has been studied.Following a calcination process that resulted in hollow spheres,the spheres’shells were coated on spherical polystyrene particle templates.The pore structures of the hollow spheres were controlled by adding a surfactant,cetyltrimethylammonium bromide(CTAB);the volume and homogeneity of the mesopores in the shell of the hollow spheres increased with increasing amount of aqueous CTAB solution.The hollow spheres with a large volume and homogeneous mesopores showed high rates of hydrogen evolution from aqueous ammonia borane solution.The highly active hollow spheres prepared with 5 mL of aqueous CTAB solution showed a considerably high turnover frequency(TOF),although the hollow spheres did not have a significantly high BET surface area or a large quantity of acid sites.This suggests that the activity for hydrogen evolution from aqueous ammonia borane solution in the presence of the hollow spheres with homogeneous mesopore structures was unexpectedly high.展开更多
基金supported by the University of Tokyo and the microstructural characterization platform of NIMS as a program of“Nanotechnology Platform”of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan.We are grateful to Mr Deguchi and Ms Wada for solidstate NMR and Mr Ito for using TEM measurement support.Additionally,we also thank Dr Yoneda for NH3-TPD measurement support.All authors contributed equally to this work.
文摘The effect of the pore structures of hollow silica–alumina composite spheres on their activity for the hydrolytic dehydrogenation of ammonia borane has been studied.Following a calcination process that resulted in hollow spheres,the spheres’shells were coated on spherical polystyrene particle templates.The pore structures of the hollow spheres were controlled by adding a surfactant,cetyltrimethylammonium bromide(CTAB);the volume and homogeneity of the mesopores in the shell of the hollow spheres increased with increasing amount of aqueous CTAB solution.The hollow spheres with a large volume and homogeneous mesopores showed high rates of hydrogen evolution from aqueous ammonia borane solution.The highly active hollow spheres prepared with 5 mL of aqueous CTAB solution showed a considerably high turnover frequency(TOF),although the hollow spheres did not have a significantly high BET surface area or a large quantity of acid sites.This suggests that the activity for hydrogen evolution from aqueous ammonia borane solution in the presence of the hollow spheres with homogeneous mesopore structures was unexpectedly high.
