In this paper, we have investigated in detail the preparation of anatase TiO 2 catalysts by the controlled thermal decomposition of ammonium titanyl sulfate ((NH 4 ) 2 TiO(SO 4 ) 2 ) and their catalytic activity. The structures of anatase TiO 2 catalysts have been characterized by powder X-ray diffraction, N 2 adsorption-desorption isotherms, diffuse reflectance UV-vis spectroscopy, infrared spectroscopy, X-ray photoemission spectroscopy, NH 3 temperature-programmed desorption, and solid-state MAS NMR spectrometer. We report for the first time that the anatase TiO 2 catalyst prepared by calcination of (NH 4 ) 2 TiO(SO 4 ) 2 at 600 °C (TiO 2 -600) is a very active bifunctional catalyst. TiO 2 -600 is doped with N and S and thus very active in the photodegradation of methyl orange under visible light illumination (λ > 420 nm); meanwhile, it also has a large number of Bro ¨nsted acid sites arising from the covalently bonded sulfuric acid groups and thus is active in the esterification of ethanol and acetic acid to ethyl acetate. The Pt/TiO 2 -600 photocatalysts with different Pt loadings were prepared via the incipient wetness impregnation method and their photocatalytic activity for the H 2 production from water splitting was evaluated with methanol as a sacrificial electron donor under both all-wavelength light and visible light (λ > 400 nm) irradiation. All Pt/TiO 2 -600 photocatalysts show considerable photocatalytic activity of water splitting. The optimum Pt loading on TiO 2 -600 is 1 and 0.1 wt % for the all-wavelength light and visible light photocatalytic reaction, respectively. Our results demonstrate a facile method to prepare highly active bifunctional TiO 2 catalysts promising in both visible-light-driven photocatalysis and acid catalysis.

The decomposition of CuH nanoparticles in aqueous solution has been successfully developed as a novel method for the preparation of Cu 2 O nanoparticles. In particular, we found that the decomposition of CuH nanoparticles in aqueous solution could be catalyzed by Au colloids, forming Cu 2 O-Au nanocomposites. The composition and structure of the resulting Cu 2 O-Au nanocomposites have been characterized in detail by inductively coupled plasma atomic emission spectroscopy, powder X-ray diffraction, N 2 adsorption-desorption isotherms, infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy. Their visible-light-driven photocatalytic activity toward various dye molecules has also been investigated. Depending on the Au:Cu ratio, Cu 2 O-Au nanocomposites exhibit different novel nanostructures including a beautiful flower-like nanostructure that consists of polycrystalline Cu 2 O, amorphous Cu 2 O and Au colloids. We propose that the rapidly-generated bubbles of H 2 during the course of the catalytic decomposition reaction drive the simultaneously-formed Cu 2 O to form amorphous curved thin foils and might also act as a template to assemble curved thin foils of amorphous Cu 2 O, polycrystalline Cu 2 O and Au colloids into uniform nanostructures. A Cu 2 O-Au nanocomposite with a Cu:Au ratio of 40 exhibits remarkable chemisorption capacity and visible-light-driven photocatalytic activity towards methyl orange and acid orange 7 and is a promising chemisorption-photocatalysis integrated catalyst. The catalytic decomposition of the metal hydride might open up a new approach for the fabrication of other metal/metal oxide nanocomposites with novel nanostructures and properties.