Direct synthesis of hydrogen peroxide from hydrogen and oxygen over a Pd core-silica shell catalyst

Pd core-silica shell particles (Pd@SiO2) were prepared by encapsulating Pd colloids with a silica shell through the Stober method. The palladium core particles were well dispersed (Dispersion = 43%) and had uniform size (4 nm) and shape inside the porous silica shell. Pd@SiO2 showed good catalytic activity (554 mmol H2O2/g Pd.h) for the direct synthesis of H2O2, which was better than those of impregnated Pd catalysts (Pd/SiO2 and Pd/Al2O3). It is expected that the stabilization of less coordinated Pd crystals in a highly dispersed state by core-shell formation is effective for the improvement of H2O2 production. (C) 2011 Elsevier B.V. All rights reserved.