Copper and platinum doped titania for photocatalytic reduction of carbon dioxide

Abstract The parent TiO 2 , platinum and copper doped TiO 2 photocatalysts with 0.5–2 wt. % of Pt, 0.5–2 wt. % Cu and 1 wt. % Pt combined with 1 wt. % Cu were prepared by the sol-gel method. All the prepared photocatalysts were tested for the CO 2 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 CH 4 , H 2 and CO were achieved in the presence of 2 wt. % Cu/TiO 2 , 0.5 wt. % Cu/TiO 2 and pure, amorphous TiO 2 . Based on the conducted experiments it was suggested that both the amount of chemisorbed oxygen or/and hydroxyl species on the TiO 2 surface and specific surface area of photocatalyst highly influence its photocatalytic activity.