Facile CeO 2 Nanoparticles Deposition on Si-Nanowires and Application to the Rhodamine B Photodegradation Under Visible Light

Abstract

The photocatalysis is a promising strategy for the water purification. In this work, Cerium dioxide Nano-particles (CeO2-NPs) were deposited by chemical electroless deposition on silicon nanowires (Si-NWs) elaborated by metal-assisted chemical etching. The obtained thin films were characterized by the combined SEM / EDX analysis. The cubic CeO2 phase was identified by X-ray diffraction (XRD) and characterized by photoluminescence (PL) while the chemical states of elements were analyzed by X-ray photoelectron spectroscopy (XPS). The optical gap (2.63–2.87 eV) were determined by UV–Vis spectrophotometry, in conformity with the white-yellow coloration. The Si-NWs/CeO2NPs Nano-composites were successfully applied as photocatalyst for the oxidation of Rhodamine B (Rh B), a recalcitrant dye under visible irradiation. The Si-NWs/CeO2 films showed a higher photocatalytic performance with a quasi total discoloration within 75 min against only 67.5% for Si-NWs. The radical trapping tests showed that the electrons (e−), •OH, O2•− and holes (h+) are mainly involved in the Rh B degradation; a reaction mechanism was suggested and discussed. This work provides new idea to develop an efficient photocatalyst to eliminate emerging pollutants from aquatic environment.