On the mechanism of the catalytic destruction of dichloromethane over Pt zeolite catalysts

Catalytic oxidation of dichloromethane (DCM, 1000 ppm) in wet air was investigated over PtHFAU catalysts differing by their Pt content (from 0 to 0.87 wt.%) the Si/Al ratio being constant and equal to 5. For a given temperature, the rate of DCM transformation is independent of the platinum particles size and of the platinum content. On the other hand, DCM oxidation into CO2 occurs through a bifunctional mechanism: DCM was firstly hydrolysed into HCl and formaldehyde on the Bronsted acid sites of the support. Afterwards, formaldehyde was oxidised into CO2 and H2O On the platinum sites. A reaction scheme was proposed to explain the complete oxidation of DCM over PtHFAU catalysts. (C) 2004 Elsevier B.V. All rights reserved.