【摘要】 尽管C2H5OH和CH3OCH3是同分异构体,但在以Ag/Al2O3为催化剂选择性催化还原NOx时,还原剂C2H5OH比CH3OCH3具有更高的活性.原位漫反射红外光谱研究表明,C2H5OH和CH3OCH3在还原NOx反应过程中分别遵循不同的反应机理:在Ag/Al2O3催化C2H5OH还原剂选择性还原NOx的反应过程中,烯醇式物种(RCH=CH-O-)和NO3-物种是主要的反应中间体,二者相互反应性能很强,可以生成反应关键中间体异氰酸酯(-NCO)表面吸附物种,因此NOx的去除率很高;而在Ag/Al2O3催化CH3OCH3还原剂选择性还原NOx的反应过程中,甲酸盐(HCOO-)物种和NO3-物种是主要的反应中间体,二者之间反应生成-NCO的活性较弱,因而NOx的去除率较低.更多还原

【Abstract】 Although C₂H₅OH and CH₃OCH₃ are isomeric compounds, C₂H₅OH is extremely efficient for NO_x reduction while it is not the case for CH₃OCH₃. In situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS） was used to study the reaction mechanism. The enolic species derived from partial oxidation of C₂H₅OH over Ag/Al₂O₃ plays a crucial role in the -NCO species formation during the selective catalytic reduction （SCR） of NO_x by C₂H₅OH. The high reactivity of the enolic species results in high surface concentration of -NCO species and high efficiency of NO_x reduction when using C₂H₅OH as a reductant. In the case of CH₃OCH₃, the formate species as a main intermediate has lower activity for the formation of -NCO species, which results in the relatively low efficiency during the SCR of NO x _.更多还原