Kinetics of liquid phase semiconductor photoassisted reactions : supporting observations for a pseudo-steady-state model

Mills, Andrew and Wang, Jishun and Ollis, David F. (2006) Kinetics of liquid phase semiconductor photoassisted reactions : supporting observations for a pseudo-steady-state model. Journal of Physical Chemistry B, 110 (29). pp. 14386-14390. ISSN 1520-6106

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    Abstract

    The kinetics of liquid phase semiconductor photocatalytic and photoassisted reactions are an area of some debate, reignited recently by an article by Ollis1 in which he proposed a simple pseudo-steady-state model to interpret the Langmuir-Hinshelwood type kinetics, commonly observed in such systems. In the current article, support for this model, over other models, is provided by a reinterpretation of the results of a study, reported initially in 1999,2 of the photoassisted mineralization of 4-chlorophenol, 4-CP, by titania films and dispersions as a function of incident light intensity, I. On the basis of this model, these results indicate that 4-CP is adsorbed more strongly on P25 TiO2 when it is in a dispersed, rather than a film form, due to a higher rate constant for adsorption, k1. In addition, the kinetics of 4-CP removal appear to depend on Iâ, where â ) 1 or 0.6 for when the TiO2 is in a film or a dispersed form, respectively. These findings are discussed both in terms of the pseudo-steady-state model and other popular kinetic models.