TY - JOUR
T1 - Tuning the photocatalytic activity of TiO2 nanoparticles by ultrathin SiO2 films grown by low-temperature atmospheric pressure atomic layer deposition
AU - Guo, Jing
AU - Benz, Dominik
AU - Doan Nguyen, Thao Trang
AU - Nguyen, Phuc Huy
AU - Thi Le, Thanh Lieu
AU - Nguyen, Hoai Hue
AU - La Zara, Damiano
AU - Liang, Bin
AU - Hintzen, Hubertus T.(Bert)
AU - van Ommen, J. Ruud
AU - Van Bui, Hao
PY - 2020
Y1 - 2020
N2 - 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.
AB - 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.
KW - Atmospheric pressure atomic layer deposition
KW - Fluidized bed reactor
KW - Low-temperature deposition
KW - Photocatalysts
KW - TiO/SiO core/shell nanoparticles
KW - Ultrathin SiO coating
UR - http://www.scopus.com/inward/record.url?scp=85088386578&partnerID=8YFLogxK
U2 - 10.1016/j.apsusc.2020.147244
DO - 10.1016/j.apsusc.2020.147244
M3 - Article
AN - SCOPUS:85088386578
SN - 0169-4332
VL - 530
JO - Applied Surface Science
JF - Applied Surface Science
M1 - 147244
ER -