The Effect of Molar Ratios of Ti/Si on Core-Shell SiO₂@TiO₂ Nanoparticles for Photocatalytic Applications

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.

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Semiconductor Quantum Dots (CdX, X = S, Te, Se) Modify Titanium Dioxide Nanoparticles for Photodynamic Inactivation of Leukemia HL60 Cancer Cells

“…TiO 2 is the most common photocatalyst and photosensitizer with the advantages of low cost, good chemical stability, low toxicity, etc. [5][6][7][8]. The holes and electrons generated by TiO 2 have excellent oxidation and reduction abilities, respectively, under the ultraviolet light irradiation [9,10].…”

Heterogeneous Fenton Oxidation Using Magnesium Ferrite Nanoparticles for Ibuprofen Removal from Wastewater: Optimization and Kinetics Studies

“…In addition, these methods are characterized by the formation of large quantities of oxidation products that are more toxic than the original pharmaceuticals [6,7]. Despite their attractiveness in the laboratory, photocatalytic methods are not widely used on an industrial scale [8,9]. This is due to their high sensitivity to the turbidity of wastewater, the complexity of the design of catalytic reactors that provide the necessary conditions for effective destruction of pollutants, and the need to use UV irradiation to achieve a high degree of mineralization of pharmaceutical contaminants [10,11].…”