Photocatalytic reduction of CO2 to hydrocarbons by using photodeposited Pt nanoparticles on carbon-doped titania

Photocatalytic reduction of CO2 with H2O was performed in a top- irradiation stainless-steel photoreactor with Pt/C-TiO2 as the photocatalyst. Pt/C-TiO2 photocatalysts with different amount of Pt (0.5-3.0 wt.%) were synthesized by the photodeposition method and were characterized in detail by X-ray powder diffraction (XRD), nitrogen physisorption measurement (BET), UV-vis diffuse reflectance spectroscopy, inductively coupled plasma optical emission spectrometry (ICP-OES), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoelectrochemical measurements. Results revealed the photocatalytic reduction of CO2 increased by loading Pt on the surface of C-TiO2. The main reaction product was methane (CH4), however, hydrogen (H-2) and carbon monoxide (CO) were also detected. The highest yields of CH4, H-2, and CO were achieved in the presence Pt/C-TiO2 with a nominal loading of 0.88 wt.%, resulting from the efficient interfacial transfer of photogenerated electrons from C-TiO2 to Pt as it is evidenced from photoelectochemical measurements.