Catalytic destruction of chlorinated POPs—Catalytic oxidation of chlorobenzene over PtHFAU catalysts

Abstract

Catalytic oxidation of monochlorobenzene (667ppm) in wet air was investigated over PtHFAU(5) catalysts, differing by their Pt content (from 0 to 1.1wt.%), their Pt dispersion (for identical Pt content) and the electronic state of Pt. PtHFAU(5) catalysts show a higher activity compared to more conventional PtAl2O3 and PtSiO2 samples.For a given temperature, chlorobenzene oxidation over PtHFAU(5) is independent of the platinum particles size. On the other hand, a plateau in activity is reached from 0.4 to 0.6% Pt.Amount of polychlorinated benzenes (PhCl2+) were produced in the order PtAl2O3>PtSiO2>PtHFAU(5). The formation of these compounds, especially PhCl2, over PtHFAU(5) was function on the Pt content (PhCl2 isomers appear only from 0.6% PtHFAU), and of the electronic state of Pt. Thus PhCl2, were mainly found over reduced Pt0 particles certainly through a chlorination of platinum (formation of PtClx species). A reaction scheme for the PhCl2 formation was proposed.