Preparation of Fe3+-doped TiO2 aerogels for photocatalytic reduction of CO2 to methanol

Developing an efficient photocatalyst to reduce CO 2 to methanol is still a major challenge. In this paper, the Fe 3+ -doped TiO 2 aerogels were prepared by sol–gel process. Implantation of Fe 3+ into TiO 2 lattice can not only narrow the band gap of electron transfer, but also suppress the recombination of photogenerated electron–hole pairs. However, when the doping content of Fe 3+ was increased to 5 mol %, partial Fe 3+ ions may enter into the lattice gap and decrease the stability of the excited electrons. The UV–Vis diffuse reflectance spectra, photoluminescence (PL) spectra, and UV-excited photoelectron spectroscopy (UPS) were used to study the effect of the Fe 3+ doping amount on the photoelectric properties of the aerogels. The photocatalytic conversion of CO 2 to methanol was used to evaluate their catalytic performances upon illumination by a 300 W Xe lamp. The corresponding band alignments indicated that the Fe 3+ -doped TiO 2 aerogels may photocatalytically reduce CO 2 to methanol. Highlights The Fe 3+ -doped TiO 2 aerogels were prepared by sol–gel process. Photocatalytic reduction of CO 2 over the Fe–TiO 2 aerogels was studied on the basis of energetic grounds. Low doping amount of Fe 3+ prolonged the lifetime of the excited electrons.