摘要
考察了CH4+O2 ,NO +CH4(+O2 )与NO2 +CH4(+O2 )反应体系中CH4的转化活性 .结果表明 ,浸渍法制备的In/HZSM 5催化剂上CH4选择还原NO过程中 ,NO2 的形成起到了活化甲烷的作用 .根据NO和NO2 在In/HZSM 5与HZSM 5样品上的TPD及IR研究结果 ,认为在载体HZSM 5的酸性位及In/HZSM 5催化剂的活性中心In位上均可形成NO2 ,NO2 与CH4的反应在In位上进行 .
CH_4 oxidations in CH_4+O_2, NO+CH_4(+O_2) and NO_2+CH_4(+O_2) reaction systems over the catalyst of indium impregnated on HZSM-5(In/HZSM-5) were studied. The efficacies of O_2, NO and NO_2 for CH_4 oxidation were evaluated. The dramatically different conversions of CH_4 in these different reaction systems suggested that NO_2 played a key role in CH_4 conversion. TPD studies of CH_4, O_2, NO and NO_2 on HZSM-5 and In/HZSM-5 were also investigated. It was found that only NO_x could absorb on the samples and the chemisorbed amount of NO_2 was much larger than that of NO. This illustrated that the absorbed NO_2 species were very important in the CH_4-SCR process. Our TPD results and IR results from the literatures both indicated that not only the acid sites but also the In sites in the In/HZSM-5 catalyst facilitated the formation of NO_2. Moreover, the reaction between NO_2 and CH_4 took place on the In sites.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2000年第7期1105-1107,共3页
Chemical Journal of Chinese Universities