Abstract
After the core-shell SiO2@TiO2 nanoparticles (CSTNs) were synthesized by hydrothermal method, we investigated the influence of different molar ratios of Ti/Si on morphology, structure, and photocatalytic activity of the CSTNs. It was found that the CSTNs showed different size and surface morphology as the Ti/Si molar ratio changed. Besides, the TiO2 and the CSTN had the anatase phase after hydrothermal process and calcination at 450°C for 2 h. The N2 adsorption-desorption isotherms demonstrated the CSTNs with the molar ratio of Ti/Si increased from 1 : 1 to 8 : 1 can be categorized as type IV with hysteresis loop of type H2 and showed to be mesoporous materials. In addition, the CSTNs with the Ti/Si molar ratio of 5 : 1 had the highest surface area of 176.79 m2/g. Surface charges showed the isoelectric point (IEP) of the CSTNs ranged between silica (IEP at pH 3.10) and titania (IEP at pH 5.29). Since the molar ratio of Ti/Si increased from 1 : 1 to 8 : 1 by degradating both colorless organic pollutant of phenol and colored substances of methylene blue (MB) under UV irradiation, the photocatalytic activity of CSTNs exhibited higher photodegradation efficiency compared with TiO2. What is more, the experimental results also showed the CSTNs with Ti/Si molar ratio of 5 : 1 had the highest photocatalytic activity and showed higher photocatalytic efficiency compared with other TiO2-SiO2 composites reported for photodegradation of phenol and MB.
Highlights
Titanium dioxide (TiO2), one of the most used photocatalysts for photodegradating inorganic and organic pollutants, has the advantages of low cost, chemical stability, low toxicity, high physical, easy availability, and excellent photoactivity [1,2,3]
The apparent surface coverage (ASC) of the core-shell SiO2@TiO2 nanoparticles (CSTNs) showed the ASC increased from 74.3% to 85.3% as the molar ratios of Ti/Si increased from 1 : 1 to 8 : 1(Table 2); the results were in accord with isoelectric point (IEP) of the CSTNs
We evaluated the morphology, structure, and other properties of the CSTNs by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area, and surface charges
Summary
Titanium dioxide (TiO2), one of the most used photocatalysts for photodegradating inorganic and organic pollutants, has the advantages of low cost, chemical stability, low toxicity, high physical, easy availability, and excellent photoactivity [1,2,3]. SiO2, due to its stable surface chemistry, low cost, mechanical stability, and facilitation of good dispersion of TiO2, is one of the significant core materials for synthesizing the core-shell nanoparticles [16]. The research that has been reported mainly focus on the morphology of the CSTNs or Journal of Nanomaterials how to control the uniform and spherical in shape, and just a few different weights or molar ratios of Ti/Si have been synthesized for photocatalysis with CSTNs. For example, Ullah et al [10] synthesized core@shell SiO2@TiO2 nanoparticles with four of different weight proportions of titanium (IV). It was found that high photocatalytic efficiency was shown with low photocatalyst addition by studying the photocatalytic activity of the CSTNs for both colorless organic pollutants (such as phenol) and colored substances (such as methylene blue)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
