Interactive Fe2O3/porous SiO2 nanospheres for photocatalytic degradation of organic pollutants: Kinetic and mechanistic approach

• Published in: Chemosphere (Oxford) 2019-11, Vol.234, p.596-607
• Main Authors: Mandal, Sandip, Adhikari, Sangeeta, Pu, Shengyan, Wang, Xiaoke, Kim, Do-Heyoung, Patel, Raj Kishore
• Format: Article
• Language: English
• Subjects: Fe2O3; Organic pollutants; photocatalyst; Photocatalytic degradation; SiO2 nanospheres
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2019.06.092

A uniformly distributed mesoporous silica nanospheres has been successfully synthesized. Silica nanospheres have been loaded with different content of Fe2O3 nanoparticles synthesized by the sol-gel process followed by calcination to form the Fe2O3 supported on silica nanospheres composite. The as-synthesized photocatalyst has been characterized for crystal structure, morphology, stability, surface area and also surface composition was determined. The photocatalytic oxidation ability of the composite photocatalyst was evaluated by degrading aqueous solutions of Methylene Blue and Congo red dyes under visible light having intense absorption in the wavelength range between 550 and 560 nm. The prime significance of silica is to act as catalyst support for uniform distribution of hematite particles for enhanced catalytic reactivity. Highest degradation has been achieved with 20 wt % loading of hematite nanoparticles indicating the less agglomeration and availability of more catalytic sites. Furthermore, colorless organic pollutants 2-chlorophenol and 2, 4-dichlorophenol have been degraded with high efficiency in the presence of H2O2 oxidizer. The scavenger experiments confirmed that hydroxyl radicals are the majorly participating species in this catalytic system. The composite system also shows good recyclability of the materials and advocates the promising nature of the designed system for multiple hazardous environmental contaminants. [Display omitted] •Uniform mesoporous silica nanospheres surface decorated with Fe2O3 nanoparticles.•Silica acts as active support for Fe2O3 nanoparticles due to the high surface area.•20 wt% Fe2O3–SiO2 photocatalyst exhibited the highest catalytic degradation.•.• HO is the major contributing species in the Fe2O3–SiO2 catalytic system.•Fe2O3–SiO2 catalyst is very stable and capable of degrading organic pollutants.