氢气对Ag/Al_2O_3和Cu/Al_2O_3催化剂选择性催化C_3H_6还原NO_x反应的影响  

Effect of H_2 on Selective Catalytic Reduction of NO_x by C_3H_6 over Ag/Al_2O_3 and Cu/Al_2O_3 Catalysts

作　　者：张秀丽[1] 贺泓[1] 余运波[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》2007年第2期117-123,共7页

基　　金：国家杰出青年科学基金(20425722);国家自然科学基金重点项目(20437010).

摘　　要：添加H2对Ag/Al2O3和Cu/Al2O3催化剂选择性催化C3H6还原NOx反应具有不同的影响.原位漫反射红外光谱分析表明,在Ag/Al2O3催化剂上,H2的存在促进了C3H6部分氧化产物烯醇式物种(RCH=CH-O-)和乙酸盐等的形成,烯醇式物种和硝酸盐为主要反应中间体,二者间的相互反应性能很强,能形成高浓度的反应关键中间体异氰酸酯(-NCO)表面吸附物种,因此NOx的去除活性提高;而在Cu/Al2O3催化剂上,H2的存在并没有促进C3H6部分氧化产物的形成,而且抑制了硝酸盐的形成,进而抑制了C3H6部分氧化产物与硝酸盐反应形成表面-NCO物种,导致NOx的去除活性降低.The effect of H2 on the selective catalytic reduction （SCR） of NOx by C3H6 was investigated over Ag/ Al2O3 and Cu/Al2O3 catalysts by steady in situ diffuse reflectance infrared Fourier transform spectroscopy. The presence of H2 might accelerate the partial oxidation of C3H6 over Ag/Al2O3 to enolic species and acetate. The enolic species can react easily with nitrates to form surface -NCO species. An enhancement of enolic species formation promoted the SCR of NOx over Ag/Al2O3 in the presence of H2. As for the Cu/Al2O3 catalyst, the addition of H2 did not influence the partial oxidation of C3H6 to acetate but inhibited apparently the formation of nitrates, and subsequently blocked the reaction between acetate and nitrates to form the key -NCO species. This led to the deactivation of Cu/Al2O3 in the SCR of NOx in the presence of H2.

关 键 词：氢 银 铜 氧化铝 氮氧化物 选择性催化还原 原位漫反射红外光谱 烯醇式物种 异氰酸酯 

分 类 号：O643.36[理学—物理化学]