Au/TiO2 lyogels have been prepared by sol-gel process followed by freeze-drying and calcination in order to induce crystallization. In the synthesis, a dispersion of AuNPs was added either during the sol-gel process or mixed with the lyogels in a ball mill after the freeze-drying. The lyogels are formed of TiO2 crystallites decorated with Au nanoparticles. The size of the TiO2 crystallites and the proportion of anatase and rutile depend on the parameters of the calcinations. The efficiency in photocatalysis diminishes with the size of the crystallites and is optimal when the lyogels include rutile together with the photoactive anatase.

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