Pt/TiO2 photocatalysts deposited on commercial support for photocatalytic reduction of CO2

Abstract

Pt/TiO2 (PC500) photocatalysts with different amount of Pt (0.5–3.0 wt.%) deposited on commercial support (Al2O3 foam) were characterized in detail by X-ray powder diffraction, nitrogen physisorption measurement, UV–vis diffuse reflectance spectroscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), photoelectrochemical measurements and tested for CO2 photocatalytic reduction and compared with commercial anatase TiO2 PC500. The main reaction product was methane; however, hydrogen and carbon monoxide were also detected. The highest yields of CH4, H2 and CO were achieved in the presence of 1.5 wt.% Pt/TiO2. Base on the performed experiments, it was suggested that the key role in the CO2 photocatalytic reduction plays the potentials of electrons and holes within the electronic structure of photocatalyst, which were markedly affected by the Pt loading in such a way that it improved the transformation efficiency of CO2 to methane. Significantly higher yields of CO2 photocatalytic reduction were achieved in the presence of photocatalysts deposited on the commercial support compared to the powder photocatalysts. These findings confirmed the great importance of the supports surface areas on photocatalyst activity in photocatalytic reaction.