原位漫反射红外光谱法研究SO_2对Ag/Al_2O_3选择性催化丙烯还原NO_x反应的影响  

Study of SO_2 Effect on the Selective Catalytic Reduction of NO_x with Propene over Ag/Al_2O_3 by in Situ DRIFTS

作　　者：吴强[1] 高洪伟[1] 贺泓[1] 

机构地区：[1]中国科学院生态环境研究中心环境化学与生态毒理学重点实验室,北京100085

出　　处：《催化学报》2006年第5期403-408,共6页

基　　金：国家杰出青年科学基金资助(20425722)

摘　　要：以Ag/Al2O3为催化剂,采用原位漫反射傅里叶变换红外光谱法研究了SO2对C3H6选择性还原NOx反应的影响.结果表明,SO2在催化剂表面转化为硫酸盐,并且随着硫酸盐累积量的增加,其主要红外特征吸收峰由低波数向高波数漂移.高浓度表面硫酸盐的存在不仅抑制了催化剂表面硝酸盐的生成,而且抑制了硝酸盐与表面烯醇式物种(RCH=CH-O-)或乙酸盐物种进一步反应,生成活泼的反应中间体异氰酸酯(-NCO),这是导致Ag/Al2O3催化剂上C3H6选择性还原NOx活性降低的主要原因.In situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） was used to investigate the effect of SO2 on the selective catalytic reduction （SCR） of NOx by C3H6 over an Ag/Al2O3 catalyst. The DRIFTS spectra showed an obvious blue shift in the band of sulfate species when its coverage over Ag/Al2O3 was increased. The sulfate species not only inhibited the formation of NO3^-, but also suppressed the reaction of enolic species or acetate species with NO3^- to form -NCO species. These behaviors are responsible for the deactivation of Ag/Al2O3 during the SCR of NOx by C3H6 in the presence of SO2.

关 键 词：银 氧化铝 氮氧化物 二氧化硫 丙烯 选择性催化还原 原位漫反射傅里叶变换红外光谱 硫酸盐 

分 类 号：O643.32[理学—物理化学]