Tuning the photocatalytic activity of TiO<sub>2</sub> nanoparticles by ultrathin SiO<sub>2</sub> films grown by low-temperature atmospheric pressure atomic layer deposition

Journal article (2020)

Authors

J. Guo Sichuan University, North University of China, ChemE/Product and Process Engineering - AS
D. Benz ChemE/Product and Process Engineering - AS
Hao Van Bui Phenikaa University, Yen Nghi
Thao Trang Doan Nguyen Quy Nhon University
Phuc Huy Nguyen Quy Nhon University
Thanh Lieu T. Le Quy Nhon University
Hoai Hue Nguyen Phenikaa University, Yen Nghi
D. La Zara ChemE/Product and Process Engineering - AS
Bin Liang Sichuan University
H.T.J.M. Hintzen RST/Luminescence Materials - AS
J.R. van Ommen ChemE/Product and Process Engineering - AS
Research Group
ChemE/Product and Process Engineering (AS) (TU Delft)
Atmospheric pressure atomic layer deposition Fluidized bed reactor Low-temperature deposition Photocatalysts TiO/SiO core/shell nanoparticles Ultrathin SiO coating
More Info
expand_more

Published Date

2020

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Faculty

Applied Sciences

Department

ChemE/Chemical Engineering

Research Group

ChemE/Product and Process Engineering

Abstract

We employed atomic layer deposition (ALD) to deposit ultrathin SiO2 layers on P25 TiO2 nanoparticles to fabricate TiO2/SiO2 core/shell nanostructures. The ALD process was carried out in a fluidized bed reactor working at atmospheric pressure using SiCl4 and H2O as precursors, enabling the deposition of SiO2 at 100 °C with the ability to control the thickness at the sub-nanometer level. By controlling the thickness of the SiO2 in a very narrow range, i.e., below 2 nm, the photocatalytic activity of TiO2 can be tuned. In particular, an enhancement was obtained for the SiO2 layers with a thickness below 1.4 nm, in which the layer with a thickness of about 0.7 nm exhibited the highest photocatalytic activity; for SiO2 layers thicker than 1.4 nm, the photocatalytic activity was strongly suppressed. The photocatalytic activity enhancement and the degradation mechanism of RhB by the TiO2/SiO2 photocatalysts were investigated by combining X-ray photoelectron spectroscopy, UV–Vis absorption spectroscopy, photoluminescence spectroscopy and the aid of charge carrier and radical scavengers. Our findings have revealed an improvement of photogenerated charge separation due to the SiO2 coating and the dominating role of hydroxyl radicals in the degradation of RhB.