Interplay between Silver and Gold Nanoparticles in Production of Hydrogen from Methanol

Hydrogen production from methanol oxidation over silver-gold/zinc oxide (AgAu/ZnO) catalysts was investigated. Bimetallic catalysts produced higher hydrogen yield and lower carbon monoxide and water yields than Ag/ZnO catalyst without deactivation during 72 h on stream at 250 degrees C. In addition, the presence of Au in the bimetallic catalyst facilitated the preferential oxidation of CO to CO2. Structural analysis of bimetallic catalysts indicated that the strong interaction between Ag and Au particles in the nano-range (4.2 nm-7.2 nm) efficiently enhanced the reducibility of non-selective silver oxide (Ag2O) species. Furthermore dispersion of metal particles in bimetallic AgAu/ZnO catalysts did not significantly change after reaction; however, dispersion of Ag species in Ag/ZnO catalyst was remarkably decreased.