Copper and platinum doped titania for photocatalytic reduction of carbon dioxide

Abstract

The parent TiO2, platinum and copper doped TiO2 photocatalysts with 0.5–2wt. % of Pt, 0.5–2wt. % Cu and 1wt. % Pt combined with 1wt. % Cu were prepared by the sol-gel method. All the prepared photocatalysts were tested for the CO2 photocatalytic reduction in a stirred batch reactor. The main reaction product was methane, however, hydrogen and carbon monoxide were also detected. The textural, (micro)structural, optical and electronic properties of photocatalysts were characterized in detail by low-temperature nitrogen physisorption, X-ray powder diffraction, EDX, HRTEM, X-ray fluorescence, X-ray photon spectroscopy, scanning electron microscope, transmission electron microscope and diffuse reflectance UV–vis spectroscopy. The photoelectrochemical characteristics of the photocatalysts were determined using photoelectric spectrometry. The highest yields of CH4, H2 and CO were achieved in the presence of 2wt. % Cu/TiO2, 0.5 wt. % Cu/TiO2 and pure, amorphous TiO2. Based on the conducted experiments it was suggested that both the amount of chemisorbed oxygen or/and hydroxyl species on the TiO2 surface and specific surface area of photocatalyst highly influence its photocatalytic activity.