New titania-based photocatalysts for hydrogen production from aqueous-alcoholic solutions of methylene blue

Abstract

A series of CuO _<i>x</i> -TiO₂ photocatalysts were prepared using fresh and thermally activated Evonik Aeroxide P25 titanium dioxide. The photocatalysts were characterized by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, XANES, diffuse reflectance spectroscopy, and N₂ adsorption technique. Photocatalytic activity of the samples was tested in hydrogen production from aqueous-alcoholic solutions of methylene blue under UV radiation (<i>λ</i> = 386 nm). It was found for the first time the synergistic effect of hydrogen production from two substrates-dye and ethanol. The maximum hydrogen production rate in the system water-ethanol-methylene blue was 1 μmol min^-1, which is 25 times higher than a value measured in a 10% solution of ethanol in water. The thermal activation of titania also leads to a change in the rate of hydrogen production. The highest catalytic activity was observed for a CuO _<i>x</i> -TiO₂ photocatalyst based on titania thermally-activated at 600 °C in air. A mechanism of the photocatalytic reaction is discussed.