Synthesis of hydrogen peroxide from H2 and O2 in water and ethanol catalyzed by nanoclustered Pd(0) on silica: strong selectivity enhancement exerted by the addition of ionic liquids

Hydrogen peroxide (H2O2) synthesis directly from dioxygen and dihydrogen was carried out using a continuous flow reactor with a Pd catalyst. The effects of ionic liquids on the selectivity to H2O2 were studied on a Pd/SiO2 catalyst. It was found that the ionic liquid [BMIM][BF4] in water or ethanol is quite beneficial to the selectivity to H2O2. Ca. 95% selectivity after 1 h in both solvents and a relatively high selectivity i.e. (about 50% in ethanol and 40% in water) after 5 h reaction have been achieved. On the other hand, a plausible mechanism for the effects of ion liquids on this reaction system was suggested on the basis of the preliminary results.