Synthesis of mesoporous Fe/h-CeO₂ hollow micro-spheres with enhanced visible light photocatalytic activity

The key to utilize the solar energy is the performance of the photocatalyst. This work presents an in situ controlled hydrothermal method for the prepared a series of Fe-doped h-CeO₂ hollow micro-spheres (X% Fe/h-CeO₂), where the dopant confers enhanced activity to the material. The micro-morphology and structure were characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS) analysis confirmed the Fe doped in the prepared microspheres with different states. The photocatalytic performance of X% Fe/h-CeO₂ samples were fully been investigated for photodegradation of RhB under visible light irradiation and showed greatly improvement of the degradation efficiency. More specifically, 0.25% Fe/h-CeO₂ achieved enhanced RhB degradation efficiency, which was 2 times than that of pure h-CeO₂. This enhancement was attributed to the reduced band gap and the doping-reduced charge recombination as conformed by the N₂ adsorption-desorption spectra and the Mott-Schottky curves respectively. The surface area of the as-prepared micro-spheres can be obviously increased by the BET. Finally, first-principle density functional (DFT) calculations confirmed that the band gap was reduced after Fe-doping, contributing to increased overlapping degree of electronic orbits. (paper)