Au/CeO2 Photocatalyst for the Selective Oxidation of Aromatic Alcohols in Water under UV, Visible and Solar Irradiation

Au nanoparticles supported on CeO2 have been prepared and investigated as photocatalysts for the photocatalytic selective oxidation of benzyl alcohol and 4-methoxybenzyl alcohol to thecorrespondent benzaldehydes, in aqueous suspensions and room conditions under UV, visible andnatural solar light irradiation. Au nanoparticles have been supported by impregnation (1 and 3 wt.%)on two types of CeO2(i.e., a commercial one and a home prepared oxide obtained in the presenceof NaOH as precipitation agent). The Au impregnated samples showed strong visible radiationabsorption at 565-570 nm associated to localized surface plasmon resonance (LSPR). The bare CeO2samples are activated by UV light and resulted virtually inactive under visible irradiation, whereasthe presence of Au improved both the conversion of the alcohols and the selectivity of the reactiontowards the aldehyde, giving rise to good results, particularly under visible and natural solar lightirradiation. The activity of the materials increased by increasing the Au content.