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Microstructure and environmental functionalities of TiO2-supported photocatalysts obtained by suspension plasma spraying

Paper ID Volume ID Publish Year Pages File Format Full-Text
49090 46547 2006 11 PDF Available
Title
Microstructure and environmental functionalities of TiO2-supported photocatalysts obtained by suspension plasma spraying
Abstract

This paper deals with the elaboration of titanium dioxide coatings, designed for photocatalytic applications, obtained by a non-conventional method of deposition, suspension plasma spraying (SPS), an alternative of the atmospheric plasma spraying (APS) in which the material feedstock is a suspension of the material powder to be sprayed. TiO2 P25 powder (Degussa AG) mechanically dispersed in distilled water and/or ethanol was injected in argon–hydrogen and argon–hydrogen–helium plasma under atmospheric conditions. Scanning electron microscopy and X-ray diffraction were performed to study the morphology and the crystalline phases of the titania coatings. Surface features were investigated by Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS). Photocatalytic efficiency of the elaborated samples was tested in an environmental test chamber set-up and evaluated from the conversion rate of nitrogen oxides.The results showed that the coating obtained from the injection of an alcoholic suspension contained 23% of anatase ratio and ensured a very low photocatalytic decomposition of nitrogen oxides. In contrast, the injection of an aqueous suspension into the plasma permitted to obtain deposits where the anatase phase and the crystallites size were preserved. Also, a conversion rate of the pollutants of about 40%, slightly better compared to that of the initial P25 powder (around 32%) was noticed. This slightly higher efficiency was correlated with a cleaning of the particles surfaces when crossing the plasma and a higher hydroxylation of the coating surface.

Keywords
Photocatalysis; TiO2; Suspension plasma spraying; Nitrogen oxides; FT-IR; XPS
First Page Preview
Microstructure and environmental functionalities of TiO2-supported photocatalysts obtained by suspension plasma spraying
Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis B: Environmental - Volume 68, Issues 1–2, 26 October 2006, Pages 74–84
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis