Efficient simultaneous removal of DPM and HC from diesel exhaust gas at low temperatures over Cu-CeO2/Al2O3 coupling with DBD plasma

Abstract

Diesel particulate matter (DPM) and hydrocarbons (HC) emitted from diesel engines negatively affect air quality and human health. Catalysts for oxidative removals of DPM and HC are currently used universally but the low removal efficiency at low temperatures is a problem. In this study, Cu-doped CeO2 loaded on Al2O3 coupled with plasma was used to enhance DPM and HC low-temperature oxidation. DPM and HC removals at 200 °C using the catalyst were as high as 90% with plasma, while below 30% without plasma. Operando plasma DRIFTS-MS was conducted to reveal the function mechanism of the oxygen species on DPM oxidation process. It was found that Cu-CeO2 can promote the formation of adsorbed oxygen (M+-O2 − ) and terminal oxygen (M=O), which can react with DPM to form carbonates that are easily converted to gaseous CO2. Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HC at low temperatures.