贵金属/BaO催化剂上NO_x的储存-还原

NO_x Storage-Reduction on Noble Metals/BaO Catalyst

运用模拟配气方法考察了贵金属(Noble Metals,NM)/BaO催化剂的氮氧化物(NOx)储存-还原性能.采用热重-差热分析(TG-DTA)法对催化剂的NOx吸附-脱附性能进行了研究.结果表明:NO2比NO更易于在催化剂上储存,O2的存在极大地促进了NOx储存反应的进行.温度对催化剂上的NOx储存行为有较大影响,在φ(O2)为16%,φ(NO)为5×10-4的氧化气氛下,NOx在NM/BaO上储存的适宜温度为300℃.300℃下催化剂的NOx吸附量可达15 mg/g,当温度升到600℃时,催化剂上的NOx能够完全脱附.使用H2在催化剂上进行NOx还原过程中,当φ(H2)为1%或3%时,还原反应速率随温度的升高而变化;φ(H2)为5%时,还原反应速率几乎不受温度影响.

The storage-reduction behavior of NOx on a Nobel Metals（NM） /BaO catalyst was investigated by means of simulating exhaust gases.The NOx adsorption-desorption performance of the NM /BaO catalyst was studied by TG-DTA（Thermogravimetric-Differential Thermal Analysis）.Results showed that NO2 was more likely to be stored on the catalyst than NO,and the presence of O2 greatly promoted the progress of the NOx storage reaction.Temperature had a significant impact on the NOx storage behavior of the catalyst.300 ℃ was the optimal temperature for NOx storage when φ（O2） was 16% and φ（NO） was 5 × 10-4.At this temperature,the adsorption capacity of NOx on NM /BaO could be up to 15 mg /g,while at 600 ℃ the NOx adsorbed by the catalyst could have complete desorption.In the course of NOx reduction by H2,the reduction rate of NOx changed with the rise of temperature when φ（H2） was 1% or 3%.In contrast,there was almost no effect from temperature when φ（H2） was 5%.