Fabrication of porous nickel–silica composite particles through catalytic hydrogen evolution reaction from aqueous ammonia borane solution

Abstract

In this work, we investigated fabrication of porous nickel–silica composite particles through catalytic hydrogen evolution reaction from aqueous solution including sodium borohydride and ammonia borane. Aggregated nickel species were observed in the samples with high nickel content from scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) results, indicating that dispersion of active nickel species was significantly influenced by nickel content. The dispersion influenced hydrogen evolution amount and rate from aqueous solution including sodium borohydride and ammonia borane, and the samples with highly dispersed active nickel species showed high hydrogen evolution amount. The particles after the hydrogen evolution process showed significantly high specific surface area with large number of nanopores. UV-Vis spectra of the samples after the hydrogen evolution process indicated that the particles with high hydrogen evolution amount from aqueous solution including sodium borohydride and ammonia borane included high amount of reduced nickel species.