铈锆复合氧化物催化HCl氧化中相互作用机制  

Interaction between CeO_2 and ZrO_2 in HCl catalytic oxidation

作　　者：费兆阳[1,2] 李磊[1,2] 成超 楼家伟 汤吉海[2] 陈献[2] 崔咪芬[2] 乔旭[1,2] FEI Zhaoyang;LI Lei;CHENG Chao;LOU Jiawei;TANG Jihai;CHEN Xian;CUI Mifen;QIAO Xu(State Key Laboratory of Materials-Oriented Chemical Engineering,Nanjing Tech University,Nanjing210009,Jiangsu,China;College of Chemical Engineering,Nanjing Tech University,Nanjing210009,Jiangsu,China)

机构地区：[1]南京工业大学材料化学工程国家重点实验室,江苏南京210009 [2]南京工业大学化工学院,江苏南京210009

出　　处：《化工学报》2018年第12期5081-5089,共9页CIESC Journal

基　　金：国家自然科学基金项目(21306089);国家科技支撑计划项目(2011BAE18B01)~~

摘　　要：采用浸渍法制备了不同负载量的ZrO_2/CeO_2·(xZr/Ce)和CeO_2/ZrO_2·(y Ce/Zr)两组催化剂。并采用XRD、Raman、N2-Sorption、TEM和H2-TPR等手段对xZr/Ce和y Ce/Zr的结构和性质进行表征,并结合HCl催化氧化活性研究CeO_2与Zr O_2在反应体系中的相互作用。结果显示,CeO_2表面掺杂适量的Zr4+可以增加xZr/Ce表面氧空位浓度,提高其HCl氧化反应活性;但当CeO_2表面掺杂过量的Zr4+,Zr元素会以ZrO_2的形式存在于xZr/Ce表面,覆盖氧空位,降低了xZr/Ce的反应活性。对于y Ce/Zr催化剂,ZrO_2表面高分散的CeO_2有利于催化活性的提高,但ZrO_2表层负载的CeO_2对催化活性的贡献具有阈值,当Ce O_2负载量超过10%后,额外增加的铈物种对催化活性已无显著促进作用;对比发现xZr/Ce的氧空位主要来自于铈锆固溶体,y Ce/Zr的氧空位主要来自于高分散的CeO_2,由铈锆固溶体产生的氧空位对活性提升更有利;与纯组分CeO_2相比,xZr/Ce与y Ce/Zr两组催化剂在苛刻条件下的长期稳定性测试中均表现出高反应稳定性。ZrO2/CeO2(xZr/Ce)and CeO2/ZrO2(yCe/Zr)catalysts with different loading were prepared by wet impregnation method.XRD,Raman,N2-Sorption,TEM and H2-TPR were used to study the interaction between CeO2and ZrO2in the recycling of Cl2from HCl oxidation.The results showed that the doping appropriate amount of zirconium species on the surface of CeO2could increase the concentration of oxygen vacancy over xZr/Ce,which was in favor of enhancing the activity of HCl oxidation.When there were too many Zr^4+doping on the surface of CeO2,a part of Zr elements would be presented as ZrO2over the surface of xZr/Ce and the oxygen vacancy was covered,which was unfavorable to the activity of HCl oxidation.For yCe/Zr catalyst,the dispersive CeO2over ZrO2was beneficial to the improvement of the catalytic activity,but the increase of catalytic activity would slow down when the loading of CeO2exceed10%.By comparing xZr/Ce with yCe/Zr catalysts,the oxygen vacancy of xZr/Ce was mainly formed by Ce-Zr solid solution,while the oxygen vacancy of yCe/Zr was formed by highly dispersive CeO2.It was found that the oxygen vacancy produced by different structure have different effects on the activity.The oxygen vacancies produced by Ce-Zr solid solution are more favorable to the activity enhancement.The ability of chlorine resistance of xZr/Ce and yCe/Zr catalysts behaved a superior stability in the long-term test compared to pure CeO2.

关 键 词：氯循环 铈锆复合氧化物 相互作用 催化 氧化 多相反应 

分 类 号：TQ028.8[化学工程]