文献类型：期刊文献

英文题名：Catalytic HCl oxidation reaction: Stabilizing effect of Zr-doping on CeO2 nano-rods

作者：Li, Chenwei[1,2];Sun, Yu[1,2];Hess, Franziska[3];Djerdj, Igor[4];Sann, Joachim[2];Voepel, Pascal[2];Cop, Pascal[2];Guo, Yanglong[1];Smarsly, Bernd M.[2];Over, Herbert[2]

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Res Inst Ind Catalysis, Key Lab Adv Mat, Shanghai 200237, Peoples R China;[2]Justus Liebig Univ, Phys Chem Inst, Heinrich Buff Ring 17, D-35392 Giessen, Germany;[3]MIT, Dept Nucl Sci & Engn, Lab Electrochem Interfaces, 77 Massachusetts Ave,13-3034, Cambridge, MA 02139 USA;[4]JJ Strossmayer Univ Osijek, Dept Chem, Ulica Cara Hadrijana 8-A, HR-31000 Osijek, Croatia

年份：2018

卷号：239

起止页码：628

外文期刊名：APPLIED CATALYSIS B-ENVIRONMENT AND ENERGY

收录：;EI(收录号：20183505756437);WOS:【SCI-EXPANDED(收录号:WOS:000446283800063)】；

基金：This work was supported by the National Key Research and Development Program of China (2016YFC0204300), National Natural Science Foundation of China (21577035), Commission of Science and Technology of Shanghai Municipality (13521103402, 15DZ1205305) and 111 Project (B08021). Chenwei Li gratefully acknowledges the China Scholarship Council for the Joint-Ph.D program between the China Scholarship Council and the Physikalisch-Chemisches Institut of the Justus-Liebig-University Giessen. We would like to thank the Center of Materials Research (LaMa) at Justus Liebig University Giessen for the support of this project.

语种：英文

外文关键词：Deacon process; Stability; CeO2; Nano-rods; Zr-doping

摘要：Mixed Ce1-xZrxO2 nano-rod particles with varying Zr doping levels of up to 20% were exposed to Deacon reaction mixtures with high HCl concentration at a reaction temperature of 430 degrees C. The mixed Ce1-xZrxO2 nano-rod samples were characterized before and after Deacon reaction by x-ray diffraction (XRD), transmission electron microscopy (TEM), and x-ray photoelectron spectroscopy (XPS). Pure CeO2 nano-rods are shown to suffer from bulk-chlorination of the catalyst (CeCl(3)x6H(2)O) for reaction mixtures HCl:O-2 > 2 that is accompanied by dramatic activity losses. For a reaction mixture of HCl:O-2 = 2.5:1, already 5% Zr doping suffices to stabilize the structure Ce1-xZrxO2 nano-rods against bulk chlorination. Although ZrCl4 is volatile above 330 degrees C, we do not encounter discharge of Zr from the fixed bed flow reactor as long as severe bulk chlorination of the Ce1-xZrxO2 catalysts in the form of CeCl3 is not observed in XRD. With a simple quasi steady-state model we can corroborate the stabilizing effect of Zr assuming that ZrCl4 evaporation is limited by diffusion of Zr4+ in the ceria-zirconia subsurface. As qunatified with XPS the chlorine concentration of stable and active Ce1-xZrxO2 nano-rods with 5% Zr is too high to be solely ascribed to on-surface chlorine. The incorporation of Cl into the surface-near region is further supported by XPS experiments performed after oxygen plasma treatment. For even more harsh reaction conditions HCl:O-2 = 3:1 none of the Ce1-xZrxO2 nano-rods was stable at 430 degrees C. However, an increase of the reaction temperature to 500 degrees C enables even pure CeO2 nano-rods to be stable under such harsh reaction conditions.