Abstract
Ce-Mn/TiO2 catalyst prepared using a simple impregnation method demonstrated a better low-temperature selective catalytic reduction of NO with NH3 (NH3–SCR) activity in comparison with the sol-gel method. The Ce-Mn/TiO2 catalyst loading with 20% Ce had the best low-temperature activity and achieved a NO conversion rate higher than 90% at 140–260°C with a 99.7% NO conversion rate at 180°C. The Ce-Mn/TiO2 catalyst only had a 6% NO conversion rate decrease after 100 ppm of SO2 was added to the stream. When SO2 was removed from the stream, the catalyst was able to recover completely. The crystal structure, morphology, textural properties and valence state of the metals involving the novel catalysts were investigated using X-ray diffraction, N2 adsorption and desorption analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive spectroscopy, respectively. The decrease of NH3–SCR performance in the presence of 100 ppm SO2 was due to the decrease of the surface area, change of the pore structure, the decrease of Ce4+ and Mn4+ concentration and the formation of the sulfur phase chemicals which blocked the active sites and changed the valence status of the elements.
Highlights
Nitrogen oxides NOx (NO, NO2, N2O) are global by-products of high-temperature combustion [1]
These results reveal that the IP method had a better low-temperature denitration activity than the SG method
The following Ce-Mn/TiO2 catalysts used in this study were prepared using the IP method
Summary
Nitrogen oxides NOx (NO, NO2, N2O) are global by-products of high-temperature combustion [1]. NOx abatement from emissions is necessary because emitted nitrogen oxides cause severe adverse health effects, acid rain and ozone layer depletion [2,3,4,5,6]. Used method because of its high denitration efficiency and wide operable temperature range [7]. The 2 SCR method refers to the process in which the reducing agent NH3 reacts with NOx with the assistance of catalyst, generating N2 and H2O [8]. The reactions involved in this process can be seen in the following equations (1.1)
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