Effect of BaO on Catalytic Activity of Pt-Rh TWC

The effect of BaO doping to the Pt-Rh catalysts on its three-way catalytic activity and water-gas transfer was investigated. The results show that the light-off temperatures of hydrocarbon and carbon monoxide and nitrogen oxides have little difference in the fresh catalysts. But after the hydrothermal-aged 5 h at 1000 ℃, the catalysts containing CeO2-ZrO2-BaO has lower light-off temperature and better catalytic activity than the catalysts containing BaO and CeO2-ZrO2,     

Influence of Ce0.35Zr0.55Y0.10 Solid Solution on Performance of Pt-Rh Three-Way Catalysts

Ce0.35Zr0.55Y0. 10 solid solution was prepared by co-precipitation technique and characterized by specific surface area measurements （BET） and X-ray diffraction （XRD）. Ce0.35Zr0.55Y0.10 was used to prepare low Pt-Rh threeway catalyst （TWC）, and its influence on the performance of TWC was investigated. The results revealed that Ce0.35 Zr0.55Y0.10 had a cubic structure similar to Ce0.50Zr0.50O2 and its specific surface area can maintain higher than Ce0.50 Zr0.50O2 after 1000 ℃ calcination for 5 h. Being hydrothermal aged at 1000 ℃ for 5 h, the catalyst containing Ce0.35 Zr0.55Y0.10 still exhibited higher conversion of C3H8, CO and NO and lower light-off temperature in comparison with Ce0.50Zr0.50O2 TWC.     

Preparation of Ce0.65Zr0.35O2 by co-precipitation： The role of hydrogen peroxide

The effect of H2O2 on the properties of Ce0.65Zr0.35O2 was explored by treating cerium nitrate and zirconium nitrate with a mixed aqueous solution of ammonia and ammonia-carbonate in the presence/absence of H2O2 . The resultant products were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption/desorption, oxygen storage capacity (OSC) and H2-temperature-programmed reduction (H2-TPR). The presence of H2O2 was found to have profound effect on powder properties such as surface area, crystallite size of the samples. It was also shown that the addition of H2O2 favored the incorporation of Zr4+ into CeO2 lattice, which facilitated the formation of CeO2-ZrO2 solid solution, and enhanced the thermal stability of the samples. OSC and H2-TPR studies indicated that the use of H2O2 enhanced the OSC and redox properties. Catalytic activity tests showed that as a support, the Ce0.65Zr0.35O2 prepared in the presence of H2O2 was more suitable for three-way catalyst. The corresponding Pd-only three-way catalyst demonstrated outstanding performance: wide air to fuel operation window, low light-off and total conversion temperature for the conversion of C3H8, NO and CO.     

Magnetic Properties and Activity of Pt-Er/γ-Al2O3 Catalysts

A series of Pt-Er/γ-Al2O3 catalysts containing 0.5%(mass fraction) platinum and 0.05%-1.5% Er were prepared by impregnation of γ-Al2O3 supported with different concentrations of erbium chloride solution. The surface properties of the catalysts were studied by methods of temperature programmed reduction and temperature programmed desorption. The magnetic behavior of Pt-Er-γ-Al2O3 catalysts were studied with a Faraday magnetic balance and the results show that the addition of Er can affect the surface properties, the catalytic activities, and magnetic behavior of the reforming catalysts. It is found that there is a corresponding relationship between the susceptibility and selectivity of Pt-Er-γ-Al2O3 catalysts. The experimental results show that Er plays the role of electron promoter.     

Synthesis of neodymium modified CeO2-ZrO2-Al2O3 support materials and their application in Pd-only three-way catalysts

Ce-Zr-Al-Nd2O3 (CZAN) support materials were prepared by co-precipitation and impregnation methods, respectively. They were characterized by X-ray diffraction (XRD), low temperature nitrogen adsorption-desorption, oxygen pulsing technique, H2-temperature pro-grammed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). The Pd-only three-way catalysts (Pd-TWC) supported on these materials were prepared by incipient wetness method and studied by activity tests. The results demonstrated that the CZAN supports obtained by the two methods showed better structural, textural and redox properties than the CZA without Nd2O3, and the addition of Nd2O3 improved the catalytic activity of TWC. Especially, the CZAN-i support prepared by impregnation method had better thermal stability and redox prop-erty. Meanwhile, the Pd/CZAN-i catalyst exhibited the best catalytic performance. XPS measurements indicated that the Nd-modified sam-ples possessed more Ce3+ and oxygen vacancies on the surface of samples, which led to a better redox property. The excellent redox property of support materials helped to improve the catalytic activity of TWC.     

Li2O、Na2O、K2O、BaO对CaO基钢包渣系性能影响的实验研究

为改善钢包渣性能以控制钢包中钢液回磷,以Li2O、Na2O、K2O、BaO作添加剂替代模拟的CaO基钢包渣系中等质量的CaO,研究添加剂对渣系的熔点、粘度和脱磷能力的影响,并推荐Li2O作为CaO基钢包 渣系的添加剂。     

Quaternary Oxide of Cerium, Terbium, Praseodymium and Zirconium for Three-Way Catalysts

Inthelastdecadethethree waycatalystshave beenremarkablyimproved.Oxygenstoragecapacity(OSC)ofthecatalystwasdeterminedbyTPR.The measuredvalueisactuallyapartoftheoxygentransfer capacity(OTC)offluorite typeoxidescontainingCe,and orPr,and orTb[1,2].Theseoxides,Ce1-x-y PrxTbyO2-δ(0≤x≤1,0≤y≤1,0≤δ≤0.5)can releasetheirlatticeoxygenwhenthetemperatureisin creasedunderdifferentoxygenpartialpressureinclud inghydrogenflow,buttheywillabsorboxygenfromits vicinityenvironmentwhenthetemperatureisde…     

Oxides Catalysts of Rare Earth and Transient Metal for Catalytic Oxidation of Benzene

The catalysts of CeO2 and the mixture of CeO2 and CuO were prepared, and the activities of these catalysts for completely oxidizing benzene were studied.The results show that the optimal proportion of CeO2/CuO is 6: 4.The highest temperature at which benzene was completely oxidized on these catalysts at different airspeed was measured.Compared these catalysts with the noble metal used, our catalysts had superiority in the resources and the industrial cost besides good activities.     

Preparation and characterization of Ce1-xFexO2 complex oxides and its catalytic activity for methane selective oxidation

A series of Ce1-xFexO2 （x=0, 0.2, 0.4, 0.6, 0.8, 1） complex oxide catalysts were prepared using the coprecipitation method. The catalysts were characterized by means of XRD and H2-TPR. The reactions between methane and lattice oxygen from the complex oxides were investigated. The characteristic results revealed that the combination of Ce and Fe oxide in the catalysts could lower the temperature necessary to reduce the cerium oxide. The catalytic activity for selective CH4 oxidation was strongly influenced by dropped Fe species. Adding the appropriate amount of Fe2O3 to CeO2 could promote the action between CH4 and CeO2. Dispersed Fe2O3 first returned to the original state and would then virtually form the Fe species on the catalyst, which could be considered as the active site for selective CH4 oxidation. The appearance of carbon formation was significant and the oxidation of carbon appeared to be the rate-determining step; the amounts of surface reducible oxygen species in CeO2 were also relevant to the activity. Among all the catalysts, Ce0.6Fe0.402 exhibited the best activity, which converted 94.52% of CH4 at 900 ℃.     

Catalytic Oxidative Properties and Characterization of CuO／CeO2 Catalysts

ＣｅＯ2 ｏｒｍａｔｅｒｉａｌｓｃｏｎｔａｉｎｉｎｇＣｅＯ2 ｐｏｓｓｅｓｓｕｎｉｑｕｅｒｅｄｏｘｐｒｏｐｅｒｔｉｅｓｉｎｃａｔａｌｙｔｉｃｐｒｏｃｅｓｓｅｓ[1～ 3] ,ａｎｄｃａｎｉｍｐｒｏｖｅｄｉｓｐｅｒｓｉｏｎｏｆａｃｔｉｖｅｃｏｍｐｏｎｅｎｔｓｏｎｔｈｅｓｕｐ ｐｏｒｔｓａｎｄｔｈｕｓｅｎｈａｎｃｅｔｈｅｉｒｔｈｅｒｍａｌｓｔａｂｉｌｉｔｙａｎｄｃａｔａｌｙｔｉｃａｃｔｉｖｉｔｙ .ＭｏｓｔｓｔｕｄｉｅｓｈａｖｅｕｓｅｄＣｅＯ2 ａｓａｎａｄｄｉｔｉｖｅ[4 ] ａｎｄｅｘａｍｉｎｅｄｉｔｓｉｎｔｅｒａ…     

Effect of Cerium on Activity of α-Amylase from Porcine Pancreas

Ｒａｒｅｅａｒｔｈｓｃａｎａｆｆｅｃｔｃｈｌｏｒｏｐｌａｓｔｕｌｔｒａ ｓｔｒｕｃｔｕｒｅ[1～ 3 ] ａｎｄｅｎｚｙｍｅａｃｔｉｖｉｔｙ[4～ 7] ,ｂｙｗｈｉｃｈｏｆｌｏｗｃｏｎｃｅｎｔｒａｔｉｏｎ ,ｂｉｏｌｏｇｉｃａｌｆｕｎｃ ｔｉｏｎｓａｒｅａｃｃｅｌｅｒａｔｅｄ ,ｂｕｔｒｅｓｔｒａｉｎｅｄａｔｈｉｇｈｃｏｎｃｅｎｔｒａｔｉｏｎ .α Ａｍｙｌａｓｅ ,ｗｈｉｃｈｂｉｎｄｓ 4ｏｒ 5ｃａｌｃｉｕｍｉｏｎｓｉｎｆｏｒｍｏｆｄｉｐｏｌｙｍｅｒ[7] ,ｐｌａｙｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｔｈｅｃｏｕｒｓｅｏ…     

渣中BaO和TiO2在常压和真空下对钢液氮含量影响

为了研究钢包顶渣中BaO和TiO2在常压和真空下对钢液氮含量的影响,选用CaO—SiO2—Al2O2碱性渣作为基础渣系,通过分析试验结果得出,在真空下渣系中的BaO和TiO2对钢液氮含量的影响作用明显强于常压条件下的作用,同时得出,无论是常压下还是真空下,向熔渣中同时添加BaO和TiO2配成的渣系对钢液脱氮作用强于单独加入。     

Effect of Novel Supporter on Catalytic Combustion of Methane

A new catalyst support, Ce-Mg-O, was prepared in a novel way macromolecule surfactant modified method and was used as a catalyst support for low-temperature methane combustion. The results indicate that the new type of FeOx/Ce- Mg-O catalyst exhibits high activity in low-temperature methane combustion, such that the T90 at which 90% conversion of methane occurs can be obtained at 560 ℃. The structure of the catalyst and the effect of the supporter on catalytic activity were characterized by transmission electronic microscopy （TEM）, X-ray diffraction （XRD）, and temperature-programmed reduction （TPR）. The results indicate that the high catalytic activity of FeOx/Ce-Mg-O over methane combustion is strongly dependent on the particle size, typical crystal phase of the Ce-Mg-O, and the interaction of FeOx and Ce-Mg-O.     

Catalytic Activity of Ceria-Zirconia Nanostructured Materials Prepared via Reversed Microemulsion Method

CeO2-ZrO2mixed oxides have a number of i mpor-tant catalytic applications[1].They are extensively em-ployed in current automotive three-way catalysts(TWCs)as the oxygen storage promoters,i.e.materi-als that regulate the oxygen partial pressure throughtheC…     

REO/γ-Al2O3催化剂上频那酮的合成研究

以特戊酸和乙酸为原料脱羧合成频那酮,首次全面考察了催化剂的制备条件对催化剂活性的影响,并对催化剂寿命、再生以及稳定性进行了研究。反应在固定床反应器中进行,采用气相色谱对合成液进行分析。结果表明,催化剂活性物质为La2O3或Pr6O11时催化活性最高;当La2O3负载量为15%,浸渍时间大于5 h,焙烧温度在560~640℃之间时制得的催化剂活性较优;催化剂寿命大于300 h,结构稳定,再生方法简单有效。     

Effect of refining slag containing Ce_2O_3 on steel cleanliness

The effect of pre-melting refining slag containing different contents of Ce2O3 on the absorption and modification of Al2O3 inclusion in an Al-killed steel was investigated through the slag/steel reaction experiment at 1600 oC.It was found that the replacement of 10 wt.% Al2O3 with Ce2O3 for 50 wt.%CaO-33 wt.%Al2O3-7 wt.%MgO-10 wt.%SiO2 refining slag promoted the slag absorption ability of alumina inclusion,which made the total oxygen content determined by infrared absorption method decrease from 100 to 25 ppm in 15 min.The Mg-Al-Ce-O type inclusion was also detected in the as-solidified samples by scanning electron microscopy(SEM).Thermodynamic analysis indicated that the Ce2O3.Al2O3 type inclusions would be formed with the cerium content in the range of 6.9 ppb to 3.6 ppm when the content of aluminum was 0.01 wt.%.     

Effect of Lanthanum on RuBPCase Activity of Tobacco Seedlings

Ｉｔｗａｓｐｒｏｖｅｄ[1] ｔｈａｔｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔｓ(ＲＥＥ)ｐｒｏｍｏｔｅｔｈｅｇｒｏｗｔｈａｎｄｄｅｖｅｌｏｐｍｅｎｔｏｆｐｌａｎｔｓ ,ａｎｄｉｎｃｒｅａｓｅｔｈｅｙｉｅｌｄｏｆｃｒｏｐｓ .Ｈｏｗ ｅｖｅｒ ,ｔｈｅｉｒｍｅｃｈａｎｉｓｍａｒｅｓｔｉｌｌｌｉｔｔｌｅｋｎｏｗｎ .ＩｔｗａｓｋｎｏｗｎｔｈａｔＲＥＥｉｎｃｒｅａｓｅｓｔｈｅａｃｔｉｖｉｔｉｅｓｏｆｓｏｍｅｅｎｚｙｍｅｓａｎｄａｃｃｅｌｅｒａｔｅｓｔｈｅｐｒｏｃｅｅｄｉｎｇｏｆｐｈｏｔｏｓｙｎｔｈｅｓｉｓｉｎｐｌａｎｔｓ …     

Catalytic Reduction of SO2 on CeO2-La2O3 Rare Earth Mixed Compounds

Adding rare earth oxide CeO2 with variable valences to La2O3 formed a mixture of rare earth oxides. By means of dipping CeO2, La2O3 and their mixture, whose carriers were all γ-Al2O3, were used as the catalyst for the reduction of SO2 by CO. The activation process of this catalyst and the impact of temperature and reactant concentration on the activation process were investigated. Using X-ray diffraction, the structure characteristics of catalyst before and after reaction were analyzed to reveal the change of phase structure. The result shows that the rare earth oxide mixtures composing of CeO2 and La2O3, as the catalyst for the reduction of SO2 by CO, diminish activation temperature 50～100℃ less and have higher activity than a single oxide CeO2 or La2O3. The reason possibl is that La2O3 goes into in the lattice of CeO2 to form solid phase complex CeO2-La2O3 and increases the capability of CeO2-La2O3/γ-Al2O3 catalyst to store oxygen, which supplies the redox of CeO2 reaction with a better condition. At the same time, elemental sulfur formed in the redox reaction impels La203 to be transformed to activation phase La2O2S in a lower temperature, which can be explained with the synergism between redox reaction and COS intermediate mechanism reaction.