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

摘要

Catalytic oxidation of dichloromethane (DCM,l000ppm) 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 CO_2 occurs through a bifunctional mechanism:DCM was firstly hydrolysed into HC1 and formaldehyde on the Br0nsted acid sites of the support.Afterwards,formaldehyde was oxidised into CO_2 and H_2O on the platinum sites.A reaction scheme was proposed to explain the complete oxidation of DCM over PtHFAU catalysts.