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

Developing an efficient photocatalyst to reduce CO₂ to methanol is still a major challenge. In this paper, the Fe³⁺-doped TiO₂ aerogels were prepared by sol–gel process. Implantation of Fe³⁺ into TiO₂ 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 Fe³⁺ was increased to 5 mol %, partial Fe³⁺ 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 Fe³⁺ doping amount on the photoelectric properties of the aerogels. The photocatalytic conversion of CO₂ to methanol was used to evaluate their catalytic performances upon illumination by a 300 W Xe lamp.