CAJ | 학술논문

采用共沉淀法制备了新型CeO2-WO3复合氧化物催化剂,并用于氨选择性催化还原(NH3-SCR)NOx反应中.活性测试表明,在200～450℃ NOx转化率接近100%.采用程序升温脱附和原位漫反射红外光谱研究了该催化剂上的NH3-SCR反应机理.结果表明,该催化剂的主要活性位是CeO2,而WO3的加入大大提高了其表面Br(o)nsted酸位的数量与强度及其氧化NO的能力.另外还发现,除了催化剂表面Lewis酸与Br(o)nsted酸参与反应外,表面的桥式与单齿硝酸盐也是活性很高的物种.整个SCR反应可通过以上两种途径进行.
채용공침정법제비료신형CeO2-WO3복합양화물최화제,병용우안선택성최화환원(NH3-SCR)NOx반응중.활성측시표명,재200～450℃ NOx전화솔접근100%.채용정서승온탈부화원위만반사홍외광보연구료해최화제상적NH3-SCR반응궤리.결과표명,해최화제적주요활성위시CeO2,이WO3적가입대대제고료기표면Br(o)nsted산위적수량여강도급기양화NO적능력.령외환발현,제료최화제표면Lewis산여Br(o)nsted산삼여반응외,표면적교식여단치초산염야시활성흔고적물충.정개SCR반응가통과이상량충도경진행.
The mechanism of NH3-selective catalytic reduction (SCR) over a CeO2-WO3 catalyst was investigated by temperature-programmed desorption (TPD) analysis and in situ diffuse reflectance infrared Fourier transform spectroscopy. The active sites were on CeO2, while WO3 greatly enhanced the amount and strength of the surface Brdnsted acid sites and the NO oxidation ability. Both NR4+ and coordinated NH3 contributed to the SCR reaction. Bridging nitrate and monodentate nitrate were confirmed as the reactive nitrate species. Under SCR reaction conditions, surface NH4NO3 was formed, which played the role of an important intermediate species. Two different pathways for the SCR reaction were suggested for the CeO2-WO3 catalyst.