SiO2-coated pure anatase TiO2 catalysts for enhanced photo-oxidation of naphthalene and anthracene--颗粒学报PARTICUOLOGY

Grover, I. S., Prajapat, R. C., Singh, S., & Pal, B. (2017). SiO2-coated pure anatase TiO2 catalysts for enhanced photo-oxidation of naphthalene and anthracene. Particuology, 34, 156-161. https://doi.org/10.1016/j.partic.2017.03.001

SiO₂-coated pure anatase TiO₂ catalysts for enhanced photo-oxidation of naphthalene and anthracene

Inderpreet Singh Grover ^a, Roop Chand Prajapat ^b, Satnam Singh ^b, Bonamali Pal ^b *

a Department of Chemistry, Public College, Samana 147101, Punjab, India
b School of Chemistry and Biochemistry, Thapar University, Patiala 147004, Punjab, India

10.1016/j.partic.2017.03.001

Volume 34, October 2017, Pages 156-161

Received 22 November 2016, Revised 18 January 2017, Accepted 10 March 2017, Available online 16 June 2017, Version of Record 12 August 2017.

E-mail: bpal@thapar.edu

Highlights

• SiO₂ coated TiO₂ nanoparticles were synthesized with different silica shell thicknesses.

• More adsorption of naphthalene/anthracene was found due to higher surface area of SiO₂ coated TiO₂.

• Silica coated TiO₂ showed higher activity for degradation of naphthalene and anthracene to CO₂.

• Complete mineralization of naphthalene and anthracene had been obtained in 240 min.

Abstract

Our current efforts reveal the preparation of SiO₂@TiO₂ nanocomposites having different thicknesses of silica shell and the relationship to photocatalytic activity (PCA) for the photo-oxidation of naphthalene and anthracene. The presence of SiO₂ coating over TiO₂ surface was demonstrated by FT-IR analysis, with peaks corresponding to Sisingle bondOsingle bondSi (1081 cm⁻¹) and Sisingle bondOsingle bondTi (950 cm⁻¹) bonds observed. High-resolution transmission electron microscopy analysis confirmed the presence of SiO₂ in the as-prepared nanocomposites and the amount of Si, Ti, and O was determined by energy dispersive X-ray spectroscopy analysis. Increasing the SiO₂ shell thickness increases the surface area of the nanocomposites (69–235 m²/g), which enhances naphthalene/anthracene adsorption. However, the observed PCA trend presents an inverse correlation to the adsorption studies, where the as-prepared samples possessing the highest surface areas exhibited the least PCA, while catalysts having lower surface areas (among silica coated samples) displayed the highest PCA in the degradation of naphthalene and anthracene to CO₂. Despite complete degradation of naphthalene and anthracene, incomplete mineralization occurred, ascribed to the formation of various intermediates, identified by GC–MS analysis.

Graphical abstract

Keywords

Silica coating; Naphthalene; Anthracene; Photo-oxidation; TiO₂ nanoparticles

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