Investigation of deactivation effect of Au addition to Ce/TiO2 catalyst for selective catalytic reduction using real diesel engine exhaust samples at low temperature conditions
2021
Keskin, Zeycan
BACKGROUND: NOₓ emissions are very toxic and cause serious adverse environmental effects. NOₓ reduction technologies have been developed due to the harmful effects of NOₓ and increasingly stringent emission standards which apply in many countries. Selective catalytic reduction (SCR) is the most effective method of removing NOₓ from engine exhaust. The suitable active catalysts are important for providing higher NOₓ conversion efficiencies in the SCR system. Catalyst production methods affect catalytic activity due to change in elemental composition, morphology, dispersion of catalytic elements, and total surface area. In this study, de‐NOₓ performance of Ce/TiO₂ and Au‐Ce/TiO₂ catalysts were investigated with real exhaust gases. Tests were carried out within 200–300 °C temperature range to evaluate low temperature performance of the catalysts. Cordierite material was used as the support material and pre‐treated with hot acid solution to enhance surface area. Ce content of synthesized catalysts with impregnation method was adjusted as 4 wt% and Au content as 0.4, 0.8, and 1.6 wt%. The catalysts were characterized with Scanning Electron Microscope (SEM), Brunauer–Emmett–Teller (BET), X‐Ray Diffractometer (XRD), and Fourier transform infrared spectroscopy (FT‐IR) analysis. RESULTS: Maximum NOₓ conversion ratios obtained at 300 °C with the Ce/TiO₂, 0.4 Au‐Ce/TiO₂, 0.8 Au‐Ce/TiO₂, and 1.6 Au‐Ce/TiO₂ catalysts were 95.1%, 92%, 92.6%, and 90.2%, respectively. CONCLUSIONS: The results showed that in general, de‐NOₓ effect of the Ce/TiO₂ catalyst was greater than the Au doped Ce/TiO₂ catalysts. Au addition adversely affected surface properties of the catalyst and therefore activity of the Au‐Ce/TiO₂ catalysts decreased. © 2021 Society of Chemical Industry (SCI).
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