Keywords: photocatalysis, biomass, titania, gold, nanoparticles, hydrogen production, ethanol photoreaction, sustainable energy, semiconductors, nanotechnology, rutile phase, anatase phase, biofuels
Ethanol photoreaction to hydrogen over Au/TiO2 catalysts. Investigating the synergistic effect of nanoparticles
Hydrogen production using photocatalytic reactions from biomass is one of the most promising methods for a sustainable energy system. Among the many complex factors affecting the reaction rate is the so–called 'synergetic or synergistic effect the phenomenon in which the combined action of two things is greater than the sum of their effects individually' of the polymorph of the semiconductor. In this work we have investigated Au/TiO
2photo–catalysts for the production of hydrogen from ethanol. We have synthesised Au particles of similar sizes on TiO
2nanoparticles also of similar sizes but of different polymorphs. It was found that Au/TiO
2anatase is about two orders of magnitude more active that Au/TiO
2rutile. Yet, it was also found that when the anatase and rutile particles are present together the reaction rate is higher than that observed over Au/TiO
2anatase alone. One possible reason for this enhancement is the increase in the number of excited electrons (rutile phase) together with a decrease in the rate of electron–hole recombination (anatase phase) at the interface.