Presentations and Publications

Chen, H., Stanier, C.O., Young, M.A., Grassian, V.H. "A Kinetic Study of Ozone Decomposition on Illuminated Oxide Surfaces." 2011, Journal of Physical Chemistry, Vol. 115, Issue 43, pp. 11979-11987.

The heterogeneous chemistry and photochemistry of ozone on oxide components of mineral dust aerosol, including alpha-Fe₂O₃, TiO₂, and alpha-Al₂O₂, at different relative humidities have been investigated using an environmental aerosol chamber. The rate and extent of ozone decomposition on these oxide surfaces are found to be a function of the nature of the surface as well as the presence of light and relative humidity. Under dark and dry conditions, only alpha-Fe₂O₃ exhibits catalytic decomposition toward ozone, whereas the reactivity of TiO₂ and alpha-Al₂O₃ is rapidly quenched upon ozone exposure. However, upon irradiation, TiO₂ is active toward O₃ decomposition and alpha-Al₂O₃ remains inactive. In the presence of relative humidity, ozone decay on alpha-Fe₂O₃ subject to irradiation or under dark conditions is found to decrease. In contrast, ozone decomposition is enhanced for irradiated TiO₂ as relative humidity initially increases but then begins to decrease at higher relative humidity levels. A kinetic model was used to obtain heterogeneous reaction rates for different homogeneous and heterogeneous reaction pathways taking place in the environmental aerosol chamber. The atmospheric implications of these results are discussed.