Au/mesoporous-TiO2 as catalyst for the oxidation of alcohols to carboxylic acids with molecular oxygen in water

Abstract Mesoporous TiO 2 ( meso -TiO 2 ) with sharp pore size distribution was synthesized by hydrothermal method. The obtained meso -TiO 2 is in pure anatase phase and presents spheric aggregates with diameter of 1.0–1.5 μm, which consists of nanoparticles with size of 6–10 nm. Au supported on meso -TiO 2 (Au/ meso -TiO 2 ) was prepared by urea deposition–precipitation method using HAuCl 4 as gold source. The catalyst was characterized by X-ray diffraction, N 2 adsorption, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy. The catalytic performance of Au/ meso -TiO 2 was studied in the oxidation of 1-pentanol to n -valeric acid with molecular oxygen as oxidant in water under basic conditions. It was found that meso -TiO 2 is a better support for gold catalyst in the oxidation of 1-pentanol than NaY zeolite, hydrotalcite, and nano-TiO 2 . Deposition–precipitation time, calcination temperature and Au loading affected the catalytic performance of Au/ meso -TiO 2 . The catalyst can also effectively catalyze the oxidation of aliphatic (C 3 –C 10 ) and aromatic alcohols to the corresponding carboxylic acids.