Low temperature selective catalytic reduction of NO by activated carbon fiber loading lanthanum oxide and ceria

Due to the contribution to air pollution, the controlling of NO discharge needs further studies. In this paper, loaded catalysts of 10-40% (w/w)CeO2/ACF were prepared by impregnation method and used for the selective catalytic reduction of NO with ammonia in the presence of O-2. Such catalysts were characterized by surface area measurement (BET), therm gravimetric (TG) analysis and Fourier transform infrared (FTIR) spectroscopy. The catalytic activity of 10-40% CeO2/ACF at different temperatures, and the catalytic stability at 200 degrees C were studied. Moreover, the experimental results were compared with those of previous studied catalysts. The results show that the 10% CeO2/ACF and 20% La2O3/ACF can yield higher NO conversion and maintain higher catalytic activity at higher temperature than others. 10% CeO2/ACF yields about 70% NO conversion in the SCR of NO at 150 degrees C, and meanwhile 20% La2O3/ACF and 10% CeO2/ACF yield over 90% NO conversion when the temperatures are higher than 350 degrees C. The catalytic activity and the catalyst stability of 10% CeO2/ACF and 20% La2O3/ACF are both higher than those of many reported catalysts. Based on the catalytic and characterizing results, such as BET, TG and FTIR, it can be found that the SCR of NO mechanism of loaded catalysts is different from those of ACF and HNO3/ACF. ACF-C is the catalyst and reducing agent in the SCR of NO of ACF and HNO3/ACF, while the metal oxides loaded by ACF are the catalytic centers, NH3 is the main reducing agent in the SCR of loaded catalysts. (c) 2010 Elsevier B.V. All rights reserved.