Enhanced photocatalytic performance of ordered mesoporous Fe-doped CeO2 catalysts for the reduction of CO2 with H2O under simulated solar irradiation

Abstract

Ordered mesoporous Fe-doped CeO2 catalysts with different Fe doping concentrations have been synthesized through a nanocasting route using ordered mesoporous SBA-15 as the template. The samples, prepared by filling mesopores in silica template with a Fe–Ce complex precursor followed by calcination and silica removal, were characterized by Raman spectroscopy, X-ray diffraction, nitrogen adsorption–desorption, transmission electron microscopy and UV–vis diffuse reflectance spectra techniques, and their catalytic activity was tested for the photocatalytic reduction of CO2 with H2O under simulated solar irradiation. It is observed that the doped Fe species can enter the lattice structure of CeO2 with a suitable doping concentration, and the obtained Fe-doped CeO2 catalysts have ordered 2D hexagonal mesostructures with high specific surface area and hierarchical porosity. Meanwhile, the introduction of Fe species can effectively extend the spectral response from UV to visible area for the catalysts which exhibited an enhanced photocatalytic performance in the reduction of CO2 with H2O when compared with non-doped mesoporous CeO2 catalyst. Further analysis by means of XPS measurement showed that the existence of mixture of Ce3+/Ce4+ oxidation states and high content of the surface chemisorbed oxygen species also contributed to the high photocatalytic activity.