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A rationale for the development of thermally stable nanostructured CeO_2-ZrO_2-containing mixed oxides 认领 引用 被引量：10
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作者 Roberta Di Monte Jan Kapar +1 位作者 Heather Bradshaw Colin Norman 《Journal of Rare Earths》 SCIE EI CAS 2008年第2期136-140,共5页
CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for... CeO2-ZeO2 solid solutions are extensively used as oxygen storage promoters in the current automotive three-way catalysts. High thermal stability of the textural properties is one of the most important requirements for practical application since temperatures up to 1273 K are easily experienced by these materials under real working conditions. In the present paper, we investigated how hydrothermal treatments applied to cakes of doped and undoped ZrO2-rich CeO2-ZrO2 precursors might improve the thermal stability of the final CeO2-ZrO2 solid solution. A rationale was developed that allowed to correlate the morphology of the hydrothermaUy treated cake with the thermal stability at 1273 K of the final product, which did not depend on the composition of the mixed oxides. 展开更多
关键词 CeO2-ZrO2 mixed oxides CeO2-ZrO2 solid solution CeO2-ZrO2 mixed oxides, thermal stability of three-way catalysts oxygen storage capacity rare earths
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Structure and catalytic property of CeO_2-ZrO_2-Fe_2O_3 mixed oxide catalysts for diesel soot combustion: Effect of preparation method 认领 引用 被引量：8
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作者 顾振华 桑秀丽 +1 位作者 王华 李孔斋 《Journal of Rare Earths》 SCIE EI CAS CSCD 2014年第9期817-823,共7页
A series of Ceo.sFeo.30Zr0.20O2 catalysts were prepared by different methods （co-precipitations method, citric acid sol-gel method, impregnation method, physical mixed method, and hydrotherrnal method） and character... A series of Ceo.sFeo.30Zr0.20O2 catalysts were prepared by different methods （co-precipitations method, citric acid sol-gel method, impregnation method, physical mixed method, and hydrotherrnal method） and characterized by X-ray diffraction （XRD）, Raman spectroscopy, Brunauer-Emmett-Teller （BET） and H2-TPR measurements. Potential of the catalysts in the soot oxidation was evaluated in a temperature-programmed oxidation （TPO） apparatus. The results showed that all the Fe3＋ and Zr4＋ were incor- porated into ceria lattice to form a pure Ce-Fe-Zr-O solid solution for the co-precipitation sample, but two kinds of Fe phases ex- isted in the Ce-Fe-Zr-O catalysts prepared by other methods： Fe3＋ incorporated into CeO2 lattice and dispersed Fe2O3 clusters. The free Fe2O3 clusters could improve the activity of catalysts for soot oxidation comparing with the pure Ce-Fe-Zr-O solid solution owing to the synergetic effect between free Fe2O3 and surface oxygen vacancies. In addition, the activity of catalysts strongly relied on the surface reducibility of free Fe2O3 particles. Holding both abundant free Fe2O3 particles and high oxygen vacancy concentration, the hydrothermal Ce0.5Fe0.3Zr0.202 catalyst presented the lowest Ti （251℃, ignition temperature of soot oxidation） and Tm （310 ℃, maximum oxidation rate temperature） for soot combustion （with tight-contact between soot and catalysts） among the five samples. Even after aging at 800 ℃ for 10 h, the Ti and Tm were still relatively low, at 273 and 361 ℃, respectively, indicating high catalytic stability. 展开更多
关键词 Ce0.5Fe0.30Zr0.20O2 mixed oxides soot combustion solid solution interaction hydrothermal method rare earths
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Properties of TiO_2-SiO_2 Mixed Oxides and Photocatalytic Oxidation of Heptane and Sulfur Dioxide 认领 引用 被引量：3
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作者 XIEChao XUZi-li YANGQiu-jing LINa WANGDe-bao DUYao-guo 《Chemical Research in Chinese Universities》 SCIE EI CAS 2005年第1期48-52,共5页
A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were ch... A series of TiO 2-XSiO 2[X denotes the molar fraction(%) of silica in the mixed oxides] with different \{n(Ti)\}(Si) ratios was prepared with ammonia water as a hydrolysis catalyst. The photocatalysts prepared were characterized by XRD, thermal analysis, FTIR, UV-Vis and SPS. The characterization results of FTIR and UV-Vis spectra show that Ti atoms were gradually changed from octahedral coordination to tetrahedral coordination with the addition of silica, which is not beneficial for obtaining strong Brnsted acidity and higher photocatalytic activity. The photocatalytic activity experiments, which were conducted by using heptane(or SO 2) as the model reactant, showed that TiO 2-SiO 2 containing a suitable amount of silica can exhibit much higher photocatalytic activity than pure TiO 2. The enhanced photocatalytic activity can be attributed to three following factors: (1) smaller crystalline size; (2) higher thermal stability; (3) the new strong Brnsted acidity. 展开更多
关键词 TiO 2-SiO 2 mixed oxide Basic hydrolysis Photocatalytic oxidation
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Catalytic reduction of SO_2 by CO over CeO_2-TiO_2 mixed oxides 认领 引用 被引量：8
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作者 张丽 秦毅红 +3 位作者 陈白珍 彭亚光 何汉兵 袁依 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第11期2960-2965,共6页
The structure and catalytic desulfurization characteristics of CeO2-TiO2 mixed oxides were investigated by means ofX-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and catalytic activity tests. Acco... The structure and catalytic desulfurization characteristics of CeO2-TiO2 mixed oxides were investigated by means ofX-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and catalytic activity tests. According to the results, a CeO2-TiO2solid solution is formed when the mole ratio of cerium to titanium n（Ce）：n（Ti） is 5：5 or greater, and the most suitable n（Ce）：n（Ti） isdetermined as 7：3, over which the conversion rate of SO2 and the yield of sulfur at 500℃ reach 93% and 99%, respectively.According to the activity testing curve, Ce0.7Ti0.3O2 （n（Ce）：n（Ti）=7：3） without any pretreatment can be gradually activated by reagentgas after about 10 min, and reaches a steady activation status 60 min later. The XPS results of Ce0.7Ti0.3O2 after different time ofSO2＋CO reaction show that CeO2 is the active component that offers the redox couple Ce4＋/Ce3＋ and the labile oxygen vacancies, andTiO2 only functions as a catalyst structure stabilizer during the catalytic reaction process. After 48 h of catalytic reaction at 500℃,Ce0.7Ti0.3O2 still maintains a stable structure without being vulcanized, demonstrating its good anti-sulfur poisoning performance. 展开更多
关键词 CeO2-TiO2 mixed oxides solid solution catalytic reduction carbon monoxide sulfur dioxide
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Effects of precursor moisture and inert N_2 atmosphere calcinations on structure and properties of alumina modified CeZrLaNd mixed oxides 认领 引用 被引量：3
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作者 Meisheng Cui Zhizhe Zhai +3 位作者 Hao Wang Yongke Hou Yongqi Zhang Xiaowei Huang 《Journal of Rare Earths》 SCIE EI CAS CSCD 2019年第6期609-616,共8页
CeO_2-ZrO_2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of ce... CeO_2-ZrO_2 mixed oxides are widely used in the three-way catalysts due to their unique reversible oxygen storage and release capacity. Large surface area, high oxygen storage capacity and good thermal stability of cerium zirconium mixed oxides are the key properties for the automotive catalysts so as to meet the strict emission regulations. In this work, alumina modified CeZrLaNd mixed oxides were prepared by a co-precipitation method. The effects of moisture in precursor and inert N2 atmosphere during calcinations on the structure and properties were investigated by Brunauer-Emmett-Teller(BET) surface area measurements, X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), hydrogen temperature-programmed reduction(H_2-TPR), oxygen storage capacity(OSC), Raman spectroscopy, and X-ray photoelectron spectroscopy(XPS). The results show that the moisture in precursor during calcinations increases the crystal grain size of the cerium zirconium mixed oxides, improving the thermal stability. And the aged surface area of sample after being calcined at1000 ℃ for 4 h reaches 68.8 m^2/g(5.7% increase compared with the common sample). The inert N2 atmosphere endows a great pore-enlarging effect, which leads to high fresh surface area of 148.9 m2/g(13.5% increase compared with the common sample) and big pore volume of 0.5705 mL/g. The redox and oxygen storage capacity are also improved by inert N2 atmosphere with high OSC value of 241.06μmolO_2/g(41.3% increase compared with the common calcination), due to the abundant formation of the crystal defects and oxygen vacancies. 展开更多
关键词 Precursor moisture Inert N2 atmosphere Calcinations Alumina modified CeZrLaNd mixed oxides Rare earths
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Preparation of Mesoporous Ce0.5Zr0.5O_2 Mixed Oxide by Hydrothermal Templating Method 认领 引用 被引量：3
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作者 古映莹 冯圣生 +2 位作者 李金林 顾向奎 王曼娟 《Journal of Rare Earths》 SCIE EI CAS 2007年第6期710-714,共5页
Mesoporous Ce0.5Zr0.5O2 mixed oxide with high specific surface area was synthesized under basic condition in the presence of non-ionic surfactant PEG-4000. The effect of synthesis conditions, such as synthesis tempera... Mesoporous Ce0.5Zr0.5O2 mixed oxide with high specific surface area was synthesized under basic condition in the presence of non-ionic surfactant PEG-4000. The effect of synthesis conditions, such as synthesis temperature and the molar ratio of PEG-4000/（[ Ce] ＋ [ Zr] ）, on specific surface area were investigated. The products were characterized by transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption-desorption measurements, respectively. The results showed that synthesis temperature and the molar ratio of PEG-4000/（[ Ce] ＋ [ Zr] ） had great influence on specific surface area. Under the optimum synthesis conditions, the prepared Ce0.5Zr0.5O2 mixed oxide presented cubic fluorite-type structure and possessed high surface area of 148.6 m2·g^-1 with wormlike pores. 展开更多
关键词 mesoporous Ce0.5Zr0.5O2 mixed oxide PEG-4000 rare earths
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Ce_xTi1-xO_2 Mixed Oxides Supported CuO Catalyst for NO Reduction by CO 认领 引用 被引量：1
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作者 楼莉萍 蒋晓原 +3 位作者 陈英旭 吕光烈 周仁贤 郑小明 《Journal of Rare Earths》 SCIE EI CAS 2003年第3期331-336,共6页
Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effects of CuO on NO+CO... Ce x Ti 1- x O 2 mixed oxides of different mole ratios ( x =0, 0.1, 0.2～0.9, 1.0) were prepared by co precipitation of TiCl 4 with Ce(NO 3) 3 and then loaded with different amounts of CuO. The effects of CuO on NO+CO reaction were investigated, and the structure and reductive properties of various CuO/Ce x Ti 1- x O 2 were characterized by the methodologies of BET, TPR and XRD. The results show that different Ce/Ti mole ratios and calcination temperatures induce changes of structure and reductive properties of the Ce x Ti 1- x O 2 mixed oxides. When x =0.1～0.5, amorphous CeTi 2O 6 phase mainly forms at 650 ℃ compared to the formation of CeTi 2O 6 which crystallizes at 800 ℃. When x >0.6, some TiO 2 enters the CeO 2 lattice and a CeO 2 TiO 2 solid solution is formed. The activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 650 ℃ is largely affected by the x values, which is the highest when x =0.3, 0.4 and 0.9. The NO conversion reaches 70% at a reaction temperature of 150 ℃. By comparison, the x values have little effect on the activity of 6%CuO/Ce x Ti 1- x O 2 calcined at 800 ℃ . There are strong interactions between CuO and CeTi 2O 6, i.e., formation of the CeTi 2O 6 phase shifts the CuO reduction peak temperature from 380 to 200 ℃, and CuO, in turn, shifts the CeTi 2O 6 reduction peak temperature from 600 to 300 ℃. 展开更多
关键词 catalitic chemistry Ce x Ti 1- x O 2 mixed oxides CuO/Ce x Ti 1- x O 2 catalysts CeTi 2O 6 phase NO+CO reaction activity rare earths
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Study on the autocatalytic mechanism of mixed resins in Na2CO3-K2CO3 melt 认领 引用
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作者 Yue-Lin Wang Yang-Hai Zheng +4 位作者 Sheng-Rong Guo Peng Huang Yun-Xue She Yun Xue Yong-De Yan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2025年第12期359-366,共8页
Thousands of radioactive mixed resins(MR)generated from nuclear industry can be processed by molten salt oxidation.There are three stages during the MSO process of MR:(1)the evaporation process(25-200℃);the thermal d... Thousands of radioactive mixed resins(MR)generated from nuclear industry can be processed by molten salt oxidation.There are three stages during the MSO process of MR:(1)the evaporation process(25-200℃);the thermal decomposition of the functional groups(200—450℃);(3)the depolymerization of styrene-divinylbenzene(450-800℃).Moreover,the thermal decomposition of the functional groups can be further divided into the thermal decomposition of the quaternary ammonium group(200-300℃)and the spitting off of the sulfonic acid group(300-450℃).NO and SO2,respectively,were produced by the destruction of these functional groups.The carbonate salt can effectively adsorb NO and SO2,whose contents decrease from 17.72%to 3.32%to 2.08%and 1.45%.Moreover,the sulfate contents in molten salt can be promoted by the generation of nitrate,which increase from 12.87%to25.44%at 500℃.The change of the standard Gibbs free energy(ΔGmθ)of the reactions about the generations of nitrate and sulfur species,and the reactions between the nitrate and sulfur species were also proved by the calculation results of HSC chemistry 6.0.Both experimental and calculated results support the finding that the generation of nitrate from MR can catalyze the further oxidation of residue. 展开更多
关键词 Molten salt oxidation Mixed resins Na2CO3-K2CO3melt Sulfonic acid group Quaternary ammonium group
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Comparative structural and electrochemical properties of mixed P2/O′3-layered sodium nickel manganese oxide prepared by sol-gel and electrospinning methods:Effect of Na-excess content 认领 引用 被引量：4
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作者 Thongsuk Sichumsaeng Atchara Chinnakorn +3 位作者 Ornuma Kalawa Jintara Padchasri Pinit Kidkhunthod Santi Maensiri 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第10期1887-1896,共10页
The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X... The effect of Na-excess content in the precursor on the structural and electrochemical performances of sodium nickel manganese oxide(NNMO)prepared by sol-gel and electrospinning methods is investigated in this paper.X-ray diffraction results of the prepared NNMO without adding Na-excess content indicate sodium loss,while the mixed phase of P2/O′3-type layered NNMO presented after adding Na-excess content.Compared with the sol-gel method,the secondary phase of NiO is more suppressed by using the electrospinning method,which is further confirmed by field emission scanning electron microscope images.N2 adsorption-desorption isotherms show no remarkably difference in specific surface areas between different preparation methods and Na-excess contents.The analysis of X-ray absorption near edge structure indicates that the oxidation states of Ni and Mn are+2 and+4,respectively.For the electrochemical properties,superior electrochemical performance is observed in the NNMO electrode with a low Na-excess content of 5wt%.The highest specific capacitance is 36.07 F·g-1at0.1 A·g-1in the NNMO electrode prepared by using the sol-gel method.By contrast,the NNMO electrode prepared using the electrospinning method with decreased Na-excess content shows excellent cycling stability of 100%after charge-discharge measurements for 300 cycles.Therefore,controlling the Na excess in the precursor together with the preparation method is important for improving the electrochemical performance of Na-based electrode materials in supercapacitors. 展开更多
关键词 sodium nickel manganese oxide mixed P2/O′3-type Na-excess content sol-gel method electrospinning method electrochemical properties
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Highly Dispersed Pd Nanoparticles Supported on Zr-Doped MgAl Mixed Metal Oxides for 2-Ethylanthraquinone Hydrogenation 认领 引用 被引量：1
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作者 Yunhao Wang Kaige Gao +3 位作者 Chenliang Ye Ang Li Cuili Guo Jinli Zhang 《Transactions of Tianjin University》 EI CAS 2019年第6期576-585,共10页
In this study,Pd-Mg(Al)-LDH/γ-Al2O3 and Pd-Mg(Al)Zr-LDH/γ-Al2O3 precursors were synthesized by impregnating Na2PdCl4 on Mg(Al)-LDH/γ-Al2O3 and Mg(Al)Zr-LDH/γ-Al2O3,and then the precursors were calcinated and reduc... In this study,Pd-Mg(Al)-LDH/γ-Al2O3 and Pd-Mg(Al)Zr-LDH/γ-Al2O3 precursors were synthesized by impregnating Na2PdCl4 on Mg(Al)-LDH/γ-Al2O3 and Mg(Al)Zr-LDH/γ-Al2O3,and then the precursors were calcinated and reduced to obtain Pd-Mg(Al)-MMO/γ-Al2O3 and Pd-Mg(Al)Zr-MMO/γ-Al2O3 catalysts.Compared with Pd/γ-Al2O3 catalyst,the hydrogenation efficiency of Pd-Mg(Al)-MMO/γ-Al2O3 and Pd-Mg(Al)Zr-MMO/γ-Al2O3 increased by 15.7%and 24.0%,respectively.Moreover,the stability of Pd-Mg(Al)Zr-MMO/γ-Al2O3 catalyst was also higher than that of Pd/γ-Al2O3.After four runs,the hydrogenation efficiency of Pd/γ-Al2O3 decreased from 12.1 to 10.0 g/L,while that of Pd-Mg(Al)Zr-MMO/γ-Al2O3 decreased from 15.0 to 14.3 g/L.The active aquinones selectivities of all catalysts were almost 99%.The structures of the catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),N2 adsorption–desorption,inductively coupled plasma-atomic emission spectrometry(ICP-AES),CO chemisorption analysis,transmission electron microscopy(TEM),temperature-programmed reduction with hydrogen(H2-TPR),and X-ray photoelectron spectroscopy(XPS).The results indicate that the improved catalytic performance is attributed to the stronger interaction between Pd and Mg(Al)Zr-MMO/γ-Al2O3,smaller Pd particle size and higher Pd dispersion.This work develops an effective method to synthesize highly dispersed Pd nanoparticles based on the layered double hydroxides(LDHs)precursor. 展开更多
关键词 LDHs precursor Mixed metal oxides Pd nanoparticles 2-Ethylanthraquinone hydrogenation Hydrogen peroxide
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Preparation and Characterization of ZrO_2 Nanoparticles Capped by Trioctylphosphine Oxide (TOPO) 认领 引用 被引量：1
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作者 马剑琪 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第4期611-614,共4页
Monodisperse ZrO2 nanoparticles capped by trioctylphosphine oxide （TOPO） were prepared in non-aqueous solvent using in-situ synthesis method. Transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray ... Monodisperse ZrO2 nanoparticles capped by trioctylphosphine oxide （TOPO） were prepared in non-aqueous solvent using in-situ synthesis method. Transmission electron microscopy（TEM）, X-ray diffraction（XRD）, X-ray photoelectron spectrometer（XPS）, Fourier transformation infrared spectroscopy （FTIR）, and thermogravimetric analysis（TGA） were adopted to characterize and investigate the size, structure, composition, and the binding manners between organic capping agent TOPO and inorganic ZrO2 nanocores of the as-prepared nanoparticles. In addition, the nanoparticles were also studied to determine their solubility and relative stability. The experimental results show that the prepared nanoparticles contain about 25% organic capping shell TOPO, 75% inorganic ZrO2 nanocores, and can be easily dissolved and be stably disersed in non-polar organic solvents. 展开更多
关键词 ZrO2 nanoparticles trioctylphosphine oxide （TOPO） monodisperse solubility
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Effect of Calcination Temperature on Structure and O_2 Desorption Properties of Ce_xPr1-xO2-δ Mixed Oxides 认领 引用
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作者 闫宗兰 石军 +2 位作者 步雅璠 赵鹏英 王谌 《Journal of Rare Earths》 SCIE EI CAS 2007年第S2期35-39,共5页
A series of CexPr1-xO2-δ (x=0, 0.5, 0.9, 1.0) mixed oxide calcined at different temperatures were synthesized by sol-gel method and characterized by Raman, XRD and O2-TPD techniques. When x=0.9, only a cubic phase Ce... A series of CexPr1-xO2-δ (x=0, 0.5, 0.9, 1.0) mixed oxide calcined at different temperatures were synthesized by sol-gel method and characterized by Raman, XRD and O2-TPD techniques. When x=0.9, only a cubic phase CeO2 is observed. When x=0.5, the compound was combined by Pr6O11 and CeO2 mixed oxides. For CexPr1-xO2-δ (x=0.5, 0.9)samples 465 cm-1 Raman peak is attributed to the Raman active F2g mode of CeO2. The broad peak at about 570 cm-1 can be linked to lattice defects resulting in oxygen vacancies. The crystallite size of the samples increased as increasing the calcined temperature. But the increased value of Ce0.9Pr0.1O2-δ and Ce0.5Pr0.5O2-δ is smaller than single CeO2 and Pr6O11 obviously. It reveals that the insertion of Pr atom into the ceria lattice could enhance the sintering resistance and thermal stability of the mixed oxides. Calcination temperatures had great effect on the peak intensity for CeO2 but less effect on Ce0.8Pr0.2O2-δ in Raman spectra, and it may be caused by the colors transformation of the mixed oxides. The result of O2-TPD experiment indicates that the formation of solid solution has elevation the stabilization and thermal stability of the mixed oxides. 展开更多
关键词 CexPr1-xO2-δ mixed oxides O2-TPD rare earths
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SiC-MoSi_2/ZrO_2-MoSi_2 coating to protect C/C composites against oxidation 认领 引用 被引量：8
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作者 付前刚 张佳平 +2 位作者 张正中 李贺军 孙粲 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第7期2113-2117,共5页
To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method.... To improve the oxidation resistance of carbon/carbon （C/C） composites in air at high temperatures, a SiC- MoSi2/ZrO2-MoSi2 coating was prepared on the surface of C/C composites by pack cementation and slurry method. The microstructures and phase compositions of the coated C/C composites were analyzed by scanning electron microscopy and X-ray diffraction, respectively. The result shows that the SiC-MoSi2/ZrO2-MoSi2 coating is dense and crack-free with a thickness of 250-300 μm. The preparation and the high temperature oxidation property of the coated composites were investigated. The as-received coating has excellent oxidation protection ability and can protect C/C composites from oxidation for 260 h at 1773 K in air. The excellent anti-oxidation performance of the coating is considered to come from the formation of ZrSiO4, which improves the stability of the coating at high temperatures. 展开更多
关键词 carbon/carbon composites SiC-MoSi2/ZrO2-MoSi2 coating oxidation resistance
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Modification of CeO2-ZrO2catalyst by potassium for NOx-assisted soot oxidation 认领 引用 被引量：11
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作者 Duan Weng Jia Li +1 位作者 Xiaodong Wu Zhichun Si 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2011年第1期145-150,共6页
Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800℃for 20 hr to evaluate the thermal stability of the catalyst.The cataly... Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method.The ageing treatment was performed in static air at 800℃for 20 hr to evaluate the thermal stability of the catalyst.The catalysts were characterized by X-ray diffraction,BET surface area,oxygen storage capacity,NOx-temperature programmed desorption and soot-temperature programmed oxidation measurements.By introduction of potassium,the maximum soot oxidation rate temperature(Tin)of the ceria-zirconia based catalyst decreased from 525 to 428℃in the presence of NO under a loose contact mode.The shift of Tm of the K-modified catalyst after ageing is only 15℃.The enhanced activity of the aged catalyst mainly lies in the promotional effect of potassium on the NOx/oxygen storage capacity as well as the soot-catalyst contact. 展开更多
关键词 CeO2-ZrO2 mixed oxides potassium soot combustion NOx storage oxygen storage capacity
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Preparation and characterization of ZrO_2/TiO_2 composite photocatalytic film by micro-arc oxidation 认领 引用 被引量：9
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作者 罗强 蔡启舟 +4 位作者 李欣蔚 潘振华 李玉洁 陈喜娣 严青松 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期2945-2950,共6页
ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （... ZrO2/TiO2 composite photocatalytic film was produced on the pure titanium substrate using in-situ Zr（OH）4 colloidal particle by the micro-arc oxidation technique and characterized by scanning electron microscope （SEM）, energy dispersive X-ray （EDX）, X-ray diffraction （XRD） and ultraviolet-visible （UV-Vis） spectrophotometer. The composite film shows a lamellar and porous structure which consists of anatase, futile and ZrO2 phases. The optical absorption edge of film is shifted to longer wavelength when ZrO2 is introduced to TiO2. Furthermore, the photocatalytic reaction rate constants of degradation of rhodamine B solution with ZrO2/TiO2 composite film and pure TiO2 film under ultraviolet irradiation are measured as 0.0442 and 0.0186 h 1, respectively. 展开更多
关键词 pure titanium micro-arc oxidation Zr（OH）4 colloidal particle ZrO2/TiO2 composite photocatalytic film
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固体超强酸SO_42-/ZrO_2-SiO_2的制备及其催化性能的研究 认领 引用 被引量：14
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作者 卢冠忠 苏勇 +1 位作者 张顺海 毛东森 《石油化工高等学校学报》 EI CAS 2007年第1期5-8,共4页
分别以氧氯化锆、硅溶胶和氨水为锆源、硅源和沉淀剂,采用共沉淀法制备Zr(OH)4-Si(OH)4,110℃干燥后经硫酸浸渍、干燥和焙烧制得SO42-/ZrO2-SiO2固体超强酸。XRD和比表面积测定结果表明,SiO2的引入对SO42-/ZrO2催化剂的结构产生了重要影... 分别以氧氯化锆、硅溶胶和氨水为锆源、硅源和沉淀剂,采用共沉淀法制备Zr(OH)4-Si(OH)4,110℃干燥后经硫酸浸渍、干燥和焙烧制得SO42-/ZrO2-SiO2固体超强酸。XRD和比表面积测定结果表明,SiO2的引入对SO42-/ZrO2催化剂的结构产生了重要影响,从而使其比表面积明显增大。以所制备的SO42-/ZrO2-SiO2固体超强酸为催化剂,代替浓硫酸用于丁酸和丁醇的酯化反应,考察了硫酸浸渍液浓度、焙烧温度等制备条件对其催化性能的影响。结果表明,采用硫酸浸渍液浓度为1.0 mol/L,焙烧温度为550℃所制备的SO42-/ZrO2-SiO2催化剂,在丁醇和丁酸的物质的量比为1.2及不添加任何带水剂的条件下,丁酸丁酯的收率高达90%以上,优于SO42-/TiO2-WO3和TiSi W12O40/TiO2催化剂。 展开更多
关键词 固体超强酸 SO4^2-/ZrO2-SiO2 丁酸丁酯
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Ce-Mn mixed oxides supported on glass-fiber for low-temperature selective catalytic reduction of NO with NH_3 认领 引用 被引量：17
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作者 李乐 刁永发 刘鑫 《Journal of Rare Earths》 SCIE EI CAS CSCD 2014年第5期409-415,共7页
Samples of cerium-manganese oxides supported on modified glass-fiber with different Ce/Mn molar ratios （Ce-Mn/GF） were prepared by an impregnation method and tested for low-temperature （80 180 ℃） selective cataly... Samples of cerium-manganese oxides supported on modified glass-fiber with different Ce/Mn molar ratios （Ce-Mn/GF） were prepared by an impregnation method and tested for low-temperature （80 180 ℃） selective catalytic reduction （SCR） of NO with ammonia. This brand-new technology could remove NO and particles matter from coal-fired flue gas. The surface properties of the catalysts were examined by means of Bmnauer-Emmett-Teller （BET）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, and scanning electron microscopy （SEM）. The experimental results showed that the catalyst with a Ce/Mn molar ratio of 0.2 obtained high activity of 87.4% NO conversion at 150 ℃ under a high space velocity of 50000 h1. Deactivation poisoned by SO2 still occurred, but the Ce-Mn/GF（0.2） catalyst performed desirable tolerance to SO2 with decreasing 50% in 40 min and then maintaining at about 30% NO conversion. Characterization results indicated that the excellent low-temperature catalytic activity was related to the high specific surface area, pore structure, and amorphous phase. 展开更多
关键词 Mn-Ce mixed oxides glass-fiber NO low-temperature SCR by NH3 SO2 poisoning rare earths
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TiO_2-SiO_2/ZrO_2催化剂的制备及催化燃烧甲苯性能 认领 引用 被引量：8
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作者 刘媛 龙千明 +2 位作者 白云鹤 吕斯濠 范洪波 《化工进展》 CAS 北大核心 2010年第11期2090-2094,2102,共5页
以ZrO2为载体,制备出TiO2-SiO2/ZrO2催化剂,用XRD和SEM对其进行表征;并将催化剂用于甲苯的催化燃烧,探讨了温度、气流速率、进气浓度等因素对甲苯催化效率和反应产物CO、CO2选择性的影响。结果表明:催化剂中的TiO2呈锐钛矿晶型,催化剂... 以ZrO2为载体,制备出TiO2-SiO2/ZrO2催化剂,用XRD和SEM对其进行表征;并将催化剂用于甲苯的催化燃烧,探讨了温度、气流速率、进气浓度等因素对甲苯催化效率和反应产物CO、CO2选择性的影响。结果表明:催化剂中的TiO2呈锐钛矿晶型,催化剂颗粒成功负载于ZrO2表面;随着温度升高,甲苯催化效率增大,350℃时能达到最大值100%,CO2选择性随之增大,但CO选择性却减少;气流速率增大导致甲苯催化效率增大,CO选择性稍稍增大,而CO2选择性减小;进气浓度从25 mg/L增加到100 mg/L时,甲苯催化效率逐渐减小,CO2选择性减小,CO选择性稍有增大。 展开更多
关键词 TiO2-SiO2/ZrO2催化剂 催化燃烧 甲苯
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Catalytic decomposition of N2O over potassium-modified Cu-Co spinel oxides 认领 引用 被引量：21
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作者 DOU Zhe ZHANG Hai-jie +1 位作者 PAN Yan-fei XU Xiu-feng 《燃料化学学报》 CSCD 北大核心 2014年第2期238-245,共8页
Cu-Co spinel oxides with different compositions were prepared for N2O catalytic decomposition in the presence ofoxygen.The active catalyst of Cu0.8Co0.2Co2O4was incipiently impregnated by alkali metal s... Cu-Co spinel oxides with different compositions were prepared for N2O catalytic decomposition in the presence ofoxygen.The active catalyst of Cu0.8Co0.2Co2O4was incipiently impregnated by alkali metal salt solutions to prepare the modifiedcatalysts.These catalysts were characterized by BET,XRD,SEM and XPS techniques,and their catalytic activity for N2Odecomposition was tested.The effect of alkali metal species,potassium precursors and potassium loadings on catalytic activity wasinvestigated.It was found that the catalytic activity of Cu0.8Co0.2Co2O4modified by K2CO3was much higher than that of bareoxide,while Cs/Cu0.8Co0.2Co2O4was inferior to Cu0.8Co0.2Co2O4for N2O decomposition.In the case of K/Cu0.8Co0.2Co2O4withdifferent potassium precursors,the catalyst activity was largely enhanced by the addition of K2CO3,while the doping of KNO3and CH3COOK notably depressed the catalytic activity.Over the optimal catalyst of 0.05K/Cu0.8Co0.2Co2O4,100%and 87.6%conversion of N2O was reached at 400℃under the atmosphere of oxygen only and oxygen-steam together,respectively.Inaddition,K2CO3-modified catalyst in both reaction atmospheres showed higher stability than un-modified catalyst. 展开更多
关键词 catalytic decomposition of N2O Cu-Co mixed oxides potassium additive catalytic activity
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制备条件对Ni/ZrO_2-SiO_2催化剂煤气甲烷化的影响 认领 引用 被引量：8
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作者 刘文燕 赵安民 +2 位作者 张海涛 应卫勇 房鼎业 《燃料化学学报》 CSCD 北大核心 2012年第1期86-92,共7页
采用浸渍法制备了ZrO2-SiO2复合载体和Ni质量分数为6%的Ni/ZrO2-SiO2催化剂,考察了载体制备时浸渍溶液pH值、焙烧温度和催化剂制备时的焙烧温度对Ni/ZrO2-SiO2催化剂煤气甲烷化反应性能的影响。采用X射线衍射、程序升温还原和扫描电子... 采用浸渍法制备了ZrO2-SiO2复合载体和Ni质量分数为6%的Ni/ZrO2-SiO2催化剂,考察了载体制备时浸渍溶液pH值、焙烧温度和催化剂制备时的焙烧温度对Ni/ZrO2-SiO2催化剂煤气甲烷化反应性能的影响。采用X射线衍射、程序升温还原和扫描电子显微镜等方法对催化剂进行了表征。结果表明,载体浸渍溶液pH值为8.0～9.0,载体焙烧温度为550℃,催化剂焙烧温度为450℃时,Ni/ZrO2-SiO2催化剂在煤气甲烷化反应中显示了最优的催化性能,CO转化率100%,CO2转化率1.8%,CH4生成速率16.6 mmol/(h.g)。进一步表征发现,制备ZrO2-SiO2复合载体时,增大浸渍溶液的pH值有利于形成粒径较小的亚稳态四方晶相ZrO2,可见四方晶相ZrO2更有利于甲烷化反应;载体焙烧温度会影响到NiO粒径的大小和其在催化剂表面的分散,温度过高和过低都会导致NiO粒径大小的不适宜以及分散性的降低;催化剂焙烧温度过高则会导致NiO与载体间的相互作用减弱,NiO分散性降低。 展开更多
关键词 镍 ZrO2-SiO2 一氧化碳 二氧化碳 甲烷化
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