Interaction between CeO2 and ZrO2 in HCl catalytic oxidation
(2.College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu, China 210009)
【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.
【Keywords】 chlorine circulation; CeO2-ZrO2; interaction; catalysis; oxidation; multiphase reaction;
 XIE X X, FEI Z Y, ZOU C, et al. Effects of rare-earth additives on structures and performances of CuO-CeO2-SiO2 catalysts for recycling Cl2 from HCl oxidation [J]. Acta Physico-Chimica Sinica, 2015, 31 (6): 1153–1161.
 MORTENSEN M, MINET R G, TSOTSIS T T, et al. A two-stage cyclic fluidized bed process for converting hydrogen chloride to chlorine [J]. Chemical Engineering Science, 1996, 51 (10): 2031–2039.
 TANG J H, CHEN X, FEI Z Y, et al. HCl oxidation to recycle Cl2 over a Cu/Ce composite oxide catalyst (Part 1): Intrinsic kinetic study [J]. Industrial & Engineering Chemistry Research, 2013, 52 (34): 11897–11903.
 DEACON H. Improvement in the manufacture of chlorine: US141333 [P]. 1873-07-18.
 CHEN X, XU X H, FEI Z Y, et al. CeO2 nanodots embedded in a porous silica matrix as an active yet durable catalyst for HCl oxidation [J]. Catalysis Science & Technology, 2016, 6 (13): 5116–5123.
 WOLF A, MLECZKO L, SCHLUTER S, et al. Processes and apparatus for the production of chlorine by gas phase oxidation: US20090304573 [P]. 2009-12-10.
 WALSDORFF C, FIENE M, ADAMI C, et al. Fixed-bed method for production of chlorine by catalytic gas-phase oxidation of hydrogen chloride: EP1542923 [P]. 2005-12-28.
 PEREZ-RAMIREZ J, MONDELLI C, SCHMIDT T, et al. Sustainable chlorine recycling via catalysed HCl oxidation: from fundamentals to implementation [J]. Energy & Environmental Science, 2011, 4 (12): 4786–4799.
 TROVARELLI A. Catalytic properties of ceria and CeO2-containing materials [J]. Catalysis Reviews—Science and Engineering, 1996, 38 (4): 439–520.
 CAO H Y, WANG J L, YAN S H, et al. Effect of doping M (M = Mn, Y) into Ce0.50Zr0.50O2 on the properties of MnOx/Ce0.50−zZr0.50−zM2zOy/Al2O3 for catalytic combustion of ethyl acetate [J]. Acta PhysicoChimica Sinica, 2012, 28 (8): 1936–1942.
 HAMMES M, VALTCHEV M, ROTH M B, et al. A search for alternative Deacon catalysts [J]. Applied Catalysis B: Environmental, 2013, 132/133 (1): 389–400.
 FARRA R, GARCIA-MELCHOR M, EICHELBAUM M, et al. Promoted ceria:a structural, catalytic, and computational study [J]. ACS Catalysis, 2015, 3 (10): 2256–2268.
 XIE X X, FEI Z Y, DAI Y, et al. Structure of ceria-based mixed oxides and its influence on HCl catalytic oxidation performance [J]. Journal of Molecular Catalysis (China), 2014, 28 (6): 507–514 (in Chinese).
 MOSER M, VILE G, COLUSSI S, et al. Structure and reactivity of ceria–zirconia catalysts for bromine and chlorine production via the oxidation of hydrogen halides [J]. Journal of Catalysis, 2015, 331: 128–137.
 XU X H, LOU J W, XIE X X, et al. Superfine CeO2 embedded in a porous ZrO2 matrix for catalytic HCl oxidation [J]. Chinese Journal of Inorganic Chemistry, 2017, 33 (3): 421–428 (in Chinese).
 XU X H, FEI Z Y, CHEN X, et al. CeO2 nanoclusters stabilized in aerogel matrix as catalysts for Cl2 production from HCl oxidation [J]. CIESC Journal, 2015, 66 (9): 3421–3427 (in Chinese).
 AMRUTE A P, MONDELLI C, MOSER M, et al. Performance, structure, and mechanism of CeO2 in HCl oxidation to Cl2 [J]. Journal of Catalysis, 2012, 286: 287–297.
 FEI Z Y, XIE X X, DAI Y, et al. HCl oxidation for sustainable Cl2 recycle over the CexZr1−xO2 catalysts: effects of Ce/Zr ratio on the activity and stability [J]. Industrial & Engineering Chemistry Research, 2014, 53 (50): 19438–19445.
 LI C, SUN Y, DJERDJ I, et al. Shape-controlled CeO2 nanoparticles: stability and activity in the catalyzed HCl oxidation reaction [J]. ACS Catalysis, 2017, 7 (10): 6453–6463.
 ATRIBAK I, AZAMBRE B, BUENO LOPEZ A, et al. Effect of NOx adsorption/desorption over ceria–zirconia catalysts on the catalytic combustion of model soot [J]. Applied Catalysis B: Environmental, 2009, 92 (1/2): 126–137.
 ZHANG Y W, WEN J, WANG J, et al. Synthesis of monodisperse CexZr1−xO2 nanocrystals and the size-dependent enhancement of their properties [J]. Nano Research, 2011, 4 (5): 494–504.
 YUAN Q, DUAN H H, LI L L, et al. Controlled synthesis and assembly of ceria-based nanomaterials [J]. Journal of Colloid and Interface Science, 2009, 335 (2): 151–167.
 THAMMACHART M, MEEVOO V, RIRKSOMBOON T, et al. Catalytic activity of CeO2–ZrO2 mixed oxide catalysts prepared via sol-gel technique: CO oxidation [J]. Catalysis Today, 2001, 68 (1/2/3): 53–61.
 WU Z, LI M, OVERBURY S H. A Raman spectroscopic study of the speciation of vanadia supported on ceria nanocrystals with defined surface planes [J]. ChemCatChem, 2012, 4 (10): 1653–1661.
 TROVARELLI A, ZAMAR F, LLORCA J, et al. Nanophase fluorite structured CeO2–ZrO2 catalysts prepared by high-energy mechanical milling-analysis of low-temperature redox activity and oxygen storage capacity [J]. Journal of Inorganic Chemistry, 1997, 169 (2): 490–502.
 FORNASIERO P, BALDUCCI G, DIMONTE R, et al. Modification of the redox behaviour of CeO2 induced by structural doping with ZrO2 [J]. Journal of Catalysis, 1996, 164 (1): 173–183.
 ZHU H, RAZZAQ R, LI C, et al. Catalytic methanation of carbon dioxide by active oxygen material CexZr1−xO2 supported NiCo bimetallic nanocatalysts [J]. AIChE Journal, 2013, 59 (7): 2567–2576.
 MONTE R D, KASPAR J. Heterogeneous environmental catalysis—a gentle art: CeO2–ZrO2 mixed oxides as a case history [J]. Catalysis Today, 2005, 100 (1/2): 27–35.
 WU X, FAN J, RAN R, et al. Effect of preparation method on the surface and redox properties of Ce0.67Zr0.33O2 mixed oxides [J]. Journal of Alloys and Compounds, 2005, 395 (1/2): 135–140.
 YESTE M P, HERNANDEZ J C, BERNAL S, et al. Redox behavior of thermally aged ceria–zirconia mixed oxides. Role of their surface and bulk structural properties [J]. Chemistry of Materials, 2006, 18 (11): 2750–2757.