Hydrogen photoproduction under visible irradiation of Au–TiO2/activated carbon

The photoproduction of hydrogen has been performed under visible light irradiation of Au–TiO2/activated carbon (AC) materials prepared by different activation methods. Results were compared against those obtained under ultraviolet irradiation. Characterization of TiO2, AC and Au–TiO2/AC was performed by adsorption–desorption N2 isotherms, surface pH (pHPZC), infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectronic spectroscopy (XPS), diffuse reflectance UV–vis spectroscopy (DR/UV–vis), and transmission electron microscopy (TEM). The present results showed that functional groups on the carbon surface are responsible to enhance 2.6 times the photocatalytic activity of Au nanoparticles deposited on TiO2. Characterization suggests that carboxylate anions detected on surface of some AC interact with metallic center at TiO2 and this surface interaction would be responsible of the enhancement in the photoactivity.