Infrared Study of Ozone Adsorption on CaO

Abstract

Ozone adsorption on CaO pretreated at different temperatures was studied by FTIR spectroscopy at 77−300 K. Besides physisorption effects, a weak complex was observed formed by ozone molecules with the OH surface groups, which have pronounced basic properties, as shown by a downward shift of the νOH band by about 21 cm-1 and by slight changes in ozone vibrational frequencies. Chemisorption of O3 occurred on CaO activated at 973 K as evidenced by the appearance of a band at 812 cm-1 accompanied by two weaker peaks at 1859 and 625 cm-1 attributed to the ν3, ν1 + ν3, and ν2 vibrational modes, respectively, of the surface ozonide O3 - ions. Experiments with 18O substitution supported this assignment. Effect of CO preadsorption showed ozone chemisorption to occur on the same coordinate-unsaturated O2- surface sites that accounted for the formation of the “carbonite” CO2 2- ion from CO adsorbed on highly activated CaO.

Catalytic Ozonation of Toluene Using Chilean Natural Zeolite: The Key Role of Brønsted and Lewis Acid Sites

“…These strong sites enhance gaseous ozone decomposition, generating active atomic oxygen (O • ), as previously reported [26,29,40,41]. Hence, the generation of a high number of active atomic oxygen species [33][34][35][36][37] could be responsible for the catalytic ozonation of toluene in a new kind of advanced oxidation process. oxygen species, leading to the observed decrease in the reaction rate of toluene catalytic oxidation (see Figure 3).…”

“…Several studies have reported the role of Lewis acid sites on the generation of active atomic oxygen species. Such species could react with adsorbed toluene on the surface of zeolite samples, as represented by Equation (2) [33][34][35][36][37]. Figure 3 shows the influence of the density of strong Lewis acid sites on the reaction rate of toluene ozonation using natural and modified zeolite as catalysts.…”

Non thermal plasma assisted catalysis of methanol oxidation on Mn, Ce and Cu oxides supported on γ-Al2O3

“…As observed by several authors [53][54][55] stabilizing on basic surface sites, which rapidly forms surface peroxide and superoxide ions.…”

Ozone decomposition on Saharan dust: an experimental investigation

“…A number of studies have been performed on the adsorption of O 3 onto various mineral oxides, using electron paramagnetic resonance, infrared spectroscopy and kinetic measurement techniques (Dhandapani and Oyama, 1997). The surfaces examined were among others: γ -Al 2 O 3 (Klimovskii et al, 1983;Bulanin et al, 1995a;Thomas et al, 1997), SiO 2 (Bulanin et al, 1994), TiO 2 (Bulanin et al, 1995a(Bulanin et al, , 1995b, CaO (Bulanin et al, 1997) and MgO (Bulanin et al, 1995a;Berlier et al, 2002). A few semi-quanitative studies on the interaction between ozone and authentic mineral dust have been published (Suzuki et al, 1979;Alebic-Juretic et al, 1992;Alebic-Juretic et al, 2000), and initial uptake coefficients for O 3 uptake onto synthetic and authentic minerals have been measured (Michel et al, 2002).…”