BACKGROUND: NO x emissions are very toxic and cause serious adverse environmental effects. NO x reduction technologies have been developed due to the harmful effects of NO x and increasingly stringent emission standards which apply in many countries. Selective catalytic reduction (SCR) is the most effective method of removing NO x from engine exhaust. The suitable active catalysts are important for providing higher NO x 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-NO x performance of Ce/TiO 2 and Au-Ce/TiO 2 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 NO x conversion ratios obtained at 300°C with the Ce/TiO 2 , 0.4 Au-Ce/TiO 2 , 0.8 Au-Ce/TiO 2 , and 1.6 Au-Ce/ TiO 2 catalysts were 95.1%, 92%, 92.6%, and 90.2%, respectively.
CONCLUSIONS:The results showed that in general, de-NO x effect of the Ce/TiO 2 catalyst was greater than the Au doped Ce/TiO 2 catalysts. Au addition adversely affected surface properties of the catalyst and therefore activity of the Au-Ce/TiO 2 catalysts decreased.