Production of H2 by Ethanol Photoreforming on Au/TiO2

A deposition-precipitation method is used to prepare Au/TiO2 solids (0.45-1.7 wt% Au). These materials, consisting of gold nanoparticles (diameter range = 1.5-6.5 nm) supported on the surface of TiO2, are used as photocatalysts for the ethanol photoreforming reaction under either UV-rich or simulated solar light. The main products of such reactions are H-2 in the gas phase and acetaldehyde in the liquid phase according to the reaction CH3CH2OH -> CH3CHO + H-2. Among the gaseous products, H-2 amounts to around or above 99% in all cases; other minor products found in the gas phase are, in decreasing order of molar production: CH4 > CO > C2H4 > CO2 > C2H6 > C3H8. The photoactivity is lower under CO2 atmosphere, as compared to analogous reactions performed under Ar. The H-2 production yields are very high (up to a maximum 30 mmol g(cat)(-1) h(-1)) under UV irradiation, and increase with increasing gold loading. The reactions under simulated solar light also yield significant amounts of H-2 (5-6 mmol g(cat)(-1) h(-1)) as the main gaseous product.