Photocatalytic activity of the binary composite CeO2/SiO2 for degradation of dye

• Published in: Applied surface science 2016-11, Vol.387, p.214-220
• Main Authors: Phanichphant, Sukon, Nakaruk, Auppatham, Channei, Duangdao
• Format: Article
• Language: English
• Subjects: Catalytic activity; CeO2; Composite materials; Degradation; Field emission; Particulate composites; Photocatalysis; Rhodamine B; Silica; Silicon dioxide; Surface chemistry; X-rays
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.06.072

[Display omitted] •The enhanced photocatalytic activity of the CeO2/SiO2 composite can be explained by the presence of the SiO2 adsorbent, which effectively increased the surface area of the CeO2.•The increased surface area of CeO2 should be helpful to facilitate more effective adsorption sites, which enhances the photocatalytic degradation of organic pollutant significantly.•SiO2 modification is effective in separating the photogenerated electrons and holes, which is of great importance for photocatalytic activity.•SiO2 acted as a carrier for CeO2 attachment and avoided the agglomeration of CeO2 particles. In this study, CeO2 photocatalyst was modified by composite with SiO2 to increase efficiency and improve photocatalytic activity. The as-prepared SiO2 particles have been incorporated into the precursor mixture of CeO2 by homogeneous precipitation and subsequent calcination process. The phase compositions of CeO2 before and after compositing with SiO2 were identified by X-ray diffraction (XRD). The morphology and particle size of CeO2/SiO2 composite was analyzed by high resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). The results showed SiO2 spheres with the particle size approximately 100–120nm, and a uniform layer of CeO2 nanoparticles with a diameter of about 5–7nm that were fully composite to the surfaces of SiO2. The X-ray photoelectron spectroscopy (XPS) technique was carried out in order to characterize the change in valence state and composite characteristic by shifted peaks of binding energies. The photocatalytic activity was studied through the degradation of Rhodamine B in aqueous solution under visible light exposure. The highest photocatalytic efficiency of CeO2/SiO2 composite was also obtained. To explain the high photocatalytic efficiency of CeO2/SiO2 composite, the proposed mechanism involves the high surface properties of the CeO2/SiO2 composite, as measured by Brunauer-Emmett-Teller (BET) method.