The effect of the nano-silica support on the catalytic reduction of water by gold, silver and platinum nanoparticles – nanocomposite reactivity

Abstract

Pt°-NPs, prepared by the reduction of Pt^IV salts with borohydride, do not catalyse the reduction of water in the presence of the strongly-reducing ˙C(CH₃)₂OH radicals. However, supporting the same metal nanoparticles (M°-NPs) with SiO₂ alters the catalytic properties enabling the reaction. This effect depends both on the nature of M° and concentration of the composite nanoparticles. At low nanocomposite concentration: for M = Au nearly no effect is observed; for M = Ag the support decreases the catalytic reduction of water and for M = Pt the support initiates the catalytic process. At high nanocomposite concentration: for M = Au the reactivity is considerably lower and for M = Ag or Pt no catalysis is observed. Furthermore, for M = Ag or Pt H₂ reduces the ˙C(CH₃)₂OH radicals.