Cu/SO_4^(2-)/La_2O_3-ZrO_2-Al_2O_3催化剂的制备及其对C_3H_6选择还原NO的催化性能  

Cu/SO_~4(2-)/La_2O_3-ZrO_2-Al_2O_3 Catalyst: Preparation and Catalytic Performance on the Selective Reduction of NO with Propylene

作　　者：郭锡坤[1] 陈庆生[1] 王小明[1] 

机构地区：[1]汕头大学化学系,汕头515063

出　　处：《无机化学学报》2006年第6期988-994,共7页Chinese Journal of Inorganic Chemistry

基　　金：广东省科技计划项目(No.2003C33004);汕头大学研究与发展项目(No.130-512042)资助。

摘　　要：以Al2O3为基质,添加ZrO2和La2O3,制成La2O3-ZrO2-Al2O3复合载体,然后采用SO42-进行改性,再负载上Cu2+,制备了铜基SO42-改性的复合载体催化剂(Cu/SO42-/La2O3-ZrO2-Al2O3)。考察了它在富氧条件下对丙烯选择还原NO的催化性能,并借助XRD、SEM、TG、Py-IR、NH3-TPD、FTIR和TPR等方法研究了Cu/SO42-/La2O3-ZrO2-Al2O3的结构和性能的关系。结果表明,ZrO2的加入主要有利于提高催化剂的低温活性;La2O3的加入则主要有利于提高催化剂的热稳定性和还原性能;SO42-能够与Zr形成螯合双配位结构,大幅度促使催化剂表面酸量增加并且酸性增强;因此,有效地提高了Cu/SO42-/La2O3-ZrO2-Al2O3在富氧条件下对丙烯选择还原NO的催化活性和水热稳定性。在无水条件下,Cu/SO42-/La2O3-ZrO2-Al2O3能使NO的最大转化率高达84.3%,即使在275℃10%水蒸气存在的情况下,仍能使NO的转化率高达81.2%。Cu/SO4^2-/La2O3-ZrO2-Al2O3 catalyst was prepared by La2O3-ZrO2-Al2O3 composite support modified with SO4^2- followed by loading with Cu^2＋. The composite support was made of Al2O3 matrix added with ZrO2 and La2O3. The catalytic effects on the selective reduction of NO by propylene in excess oxygen were investigated. The relationship of structure and property of Cu/SO4^2-/La2O3-ZrO2-Al2O3 catalyst was also explored by means of XRD, SEM, TG, Py-IR, NH3-TPD, FTIR and TPR. The results indicate that the addition of ZrO2 contributes mainly to the increase of the catalytic activity in low temperature of the title catalyst; whilst the addition of La2O3 contributes mainly to the enhancement of the thermal stability and reducibility of the catalyst; the SO4^2- is able to combine with Zr to form a chelate bidentate state favorable for an increase of the acid quantity on the surface of the catalyst and the acidity. Consequently, the catalytic activity and hydrothermal stability of the catalyst to the selective reduction of NO with propylene in excess oxygen have been improved effectively. Under the condition free from water vapor, Cu/SO4^2-/La2O3-ZrO2-Al2O3 catalyst could make the conversion rate of NO up to a degree of 84.3%,even at temperature of 275℃ with the present of 10% water vapor, the conversion rate of NO could also reach to 81.2%.

关 键 词：La2O3-ZrO2-Al2O3 SO4^2-改性 水热合成法 丙烯选择还原NO 

分 类 号：O643.36[理学—物理化学] TQ426.6[理学—化学]