Total oxidation of carbon monoxide, VOC and reduction of NO₂ with catalytic ceramic filter media

This paper deals with the effect of catalyst loading on the activity and selectivity of CuOx MnOy catalysts on alumina-silicate supports (fiber material-Al2O3(44)/SiO2(56)). A special focus lies on the oxidation of CO, on mixtures of VOC from 1-butene, isobutane, n-butane, propane, ethene, and ethane, as well as on CO oxidation in the presence of NO2. The catalysts are prepared through wet impregnation of the filter section with an aqueous solution of copper and manganese nitrate. The rate of CO oxidation for small carbon monoxide concentrations of up to 1 vol.% is independent of catalyst loading in the filter material. In contrast, at a carbon monoxide concentration of around 3 vol.%, it is found that the rate of CO oxidation increased rapidly with increasing catalyst loading of the filter material. The highest catalytic activity of over 93% CO elimination is achieved at 290 ◦C for 1 vol.% CO and smaller catalyst loading and for 3 vol.% CO with higher catalyst loading. In long-term stability tests, complete CO conversion is measured without deactivating the catalyst at 390 ◦C for at least 100 h. The highest catalytic activity for VOC elimination of 90% is achieved in the temperature range of 350–420 ◦C. During the CO–NO2 reaction with and without O2, a constant decrease in the CO oxidation rate is observed, while the NO2 reduction rate remained constant at a temperature below 300 ◦C