TiO2–Pd/C composited photocatalyst with improved photocatalytic activity for photoreduction of CO2 into CH4.

A novel Pd-modified TiO2 photocatalyst composited with carbon nanoparticles (TiO2–Pd/C) was synthesized via a sol–gel method. Characterized by XRD, Raman, BET, HRTEM, EDAX, XPS, absorption spectra and PL techniques, the introduced Pd existed as unique O–Pd–O species, and C existed as the substance carbon nanoparticles on the surface of TiO2, behaving as a composited photocatalyst on a nanoscale. Based on the experimental results and theoretical calculations, it was found that the introduction of O–Pd–O surface species and the carbon nanoparticles extend the absorption into the visible light region and facilitate the separation of photogenerated charge carriers, resulting in a much better photocatalytic activity of the photo-reduction of CO2 into CH4, than would be achieved with TiO2–Pd and TiO2/C samples. [ABSTRACT FROM AUTHOR]