Improvement of NOx and CO Reduction Performance at Low Temperature of H2-SCR Catalyst

Abstract

The purpose of this study is to improve the simultaneous reduction of NOX and CO, harmful gases emitted from internal combustion engines, at low temperatures using a Pt/TiO2 H2-SCR catalyst. A better NOX/CO reduction performance was observed upon loading 2 wt% of the additive catalyst CeO2 on the main catalyst Pt because the oxygen storage capacity improved. In the presence of CO, the water gas reaction was promoted, resulting in the NOX conversion rate by the 0.5Pt−2CeO2/TiO2 SCR catalyst of 42 % at 75 °C and 70 % at 100 °C; this was a 15 ∼ 20 % higher NOX conversion as compared to without CO at low temperatures. The NOX reduction performance by the 0.5Pt−2CeO2−2ZrO2/TiO2 SCR catalyst was the highest at temperatures below 100 °C. At an appropriate amount of the additive catalyst ZrO2, the reaction rate improved because the acid point of the catalyst surface and the intensity of adsorption are adjusted. The optimum reduction temperature for NOX/CO reduction performance by the H2-SCR catalyst was 400 °C. Our results also indicate that the Pt species has a significant impact.