Abstract
The effect of H2O and O2 on the adsorption and degradation of gaseous acetaldehyde on the anatase TiO2 surface has been studied, in the dark and upon UV illumination, at ambient temperatures. The processes occurring at the surface have been elucidated by means of in situ ATR–FTIR (Attenuated Total Reflection—Fourier Transform Infrared) spectroscopy, while gas detectors allowed the analysis of the adducts and products in the gas phase. In the dark and under dry conditions acetaldehyde reacts independently of the atmosphere, upon aldol condensation to crotonaldehyde. However, under humid conditions, this reaction was prevented due to the replacement of the adsorbed acetaldehyde molecules, by water molecules. Upon UV illumination under oxygenic conditions, acetaldehyde was decomposed to acetate and formate. Under an N2 atmosphere, the formation of acetate and formate was observed during the first hour of illumination, until all adsorbed oxygen had been consumed. In the absence of molecular oxygen acetate, methane, and CO2 were detected, the formation of which most likely involved the participation of the bridging O atoms, within the TiO2 lattice.
Highlights
Nowadays, the demand for clean and fresh indoor air is a public health issue
In situ ATR–FTIR (Attenuated Total Reflection–Fourier Transform Infrared) spectroscopy is an established technique that provides a deeper understanding of the interfacial processes occurring at the semiconductor/water interface
When a TiO2 film was treated with 1000 ppb gaseous
Summary
One major indoor air pollutant is acetaldehyde, which is a potential human carcinogen [1], whose maximum occupational exposure levels are set in Europe, and in the USA [2,3]. In situ ATR–FTIR (Attenuated Total Reflection–Fourier Transform Infrared) spectroscopy is an established technique that provides a deeper understanding of the interfacial processes occurring at the semiconductor/water interface. This technique allows the monitoring of the molecule adsorption from gaseous and from liquid phase on solid surfaces, as well as the detection of intermediates and products of photocatalytic processes [5,6]
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.