Authors (3): S. Alofi, C. O'Rourke, A. Mills
Themes: Water-Energy (2023)
DOI: 10.1021/acs.jpcc.3c00952
Citations: 0
Pub type: journal-article
Publisher: American Chemical Society (ACS)
Issue: 25
License: [{"start"=>{"date-parts"=>[[2023, 6, 20]], "date-time"=>"2023-06-20T00:00:00Z", "timestamp"=>1687219200000}, "content-version"=>"vor", "delay-in-days"=>0, "URL"=>"https://creativecommons.org/licenses/by/4.0/"}]
Publication date(s): 2023/06/29 (print) 2023/06/20 (online)
Pages: 12194-12205
Volume: 127 Issue: 25
Journal: The Journal of Physical Chemistry C
URL: http://dx.doi.org/10.1021/acs.jpcc.3c00952The kinetics of the removal of stearic acid (SA) islands by photocatalytic coatings is controversial, with some reporting that the islands fade as their thickness, h, decreases with the irradiation time, t, but maintain a constant area, a, −da/dt = 0, and others reporting that −dh/dt = 0 and −da/dt = −constant, i.e., the islands shrink, rather than fade. This study attempts to understand the possible cause for these two very different observations through a study of the destruction of a cylindrical SA island and an array of such islands, on two different photocatalytic films, namely, Activ self-cleaning glass, and a P25 TiO2 coating on glass, which have established uniform and heterogeneous surface activities, respectively. In both cases, using optical microscopy and profilometry, it is shown that, irrespective of whether there is as a single cylindrical island or an array of islands, h decreases uniformly with t, −dh/dt = constant, and −da/dt = 0, so that the SA islands just fade. However, in a study of the photocatalyzed removal of SA islands with a volcano-shaped profile, rather than that of a cylinder, it is found that the islands shrink and fade. A simple 2D kinetic model is used to rationalize the results reported in this work. Possible reasons for the two very different kinetic behaviors are discussed. The relevance of this work to self-cleaning photocatalytic films is discussed briefly.
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jp3c00952_si_001.pdf | Electronic Supl. Information (ESI) Study and modeling of the kinetics of... | 2023 |