Pt/titania-nanotube: A potential catalyst for CO2 adsorption and hydrogenation

The titania-nanotube-supported Pt (Pt/Tnt) catalyst was prepared by the photochemical deposition of Pt complex on the titania-nanotube (Tnt) synthesized by the alkaline hydrothermal method. The physicochemical properties of Pt/Tnt catalyst were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, N2 adsorption and desorption isotherms, temperature-programmed reduction and X-ray photoelectron spectroscopy. The Pt/Tnt catalyst exhibited mixed-valence Pt nanoparticles (1–3 nm) dispersed uniformly on the surface of Tnt with a Brunauer–Emmett–Teller surface area of 187 m2/g. The results of the temperature-programmed desorption of CO2 indicated the CO2 adsorption capacity of Tnt was highly enhanced by the supported Pt nanoparticles. In situ Fourier-transform infrared spectroscopy demonstrated that the Pt/Tnt catalyst was highly active for the CO2 hydrogenation toward methane production at relatively low temperature of 100 °C.