Interaction between CeO2 and ZrO2 in HCl catalytic oxidation

Literature information

Author：

FEI Zhaoyang1,2 LI Lei1,2 CHENG Chao1,2 LOU Jiawei1,2 TANG Jihai2 CHEN Xian2 CUI Mifen2 QIAO Xu1,2

Affiliations：

State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu, China 210009;College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu, China 210009

Year：

2018

Keywords：

chlorine circulation; CeO2-ZrO2; interaction; catalysis; oxidation; multiphase reaction;

Abstract：

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 CeO2 and ZrO2 in the recycling of Cl2 from HCl oxidation. The results showed that doping appropriate amount of zirconium species on the surface of CeO2 could increase the concentration of oxygen vacancy over xZr/Ce, which was in favor of enhancing the activity of HCl oxidation. When there was too much Zr4+ doping on the surface of CeO2, a part of Zr elements would be presented as ZrO2 over the surface of xZr/Ce and the oxygen vacancy was covered, which was unfavorable to the activity of HCl oxidation. For yCe/Zr catalysts, the dispersive CeO2 over ZrO2 was beneficial to the improvement of the catalytic activity, but the increase of catalytic activity would slow down when the loading of CeO2 exceeded 10%. 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 structures had different effects on the activity. The oxygen vacancies produced by Ce-Zr solid solution were more favorable to the activity enhancement. The ability of chlorine resistance of xZr/Ce and yCe/Zr catalysts showed superior stability in the long-term test compared to pure CeO2.