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Pr-Zr固溶体的制备及其氧化性能研究 被引量:2
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作者 杜云鹏 魏永刚 +2 位作者 王华 李孔斋 祝星 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2014年第4期891-895,共5页
通过共沉淀法制备了Pr0.7Zr0.3O2-δ复合氧化物氧载体,考察了制备温度、老化时间、pH以及母液浓度对Pr-Zr固溶体形成的影响,借助XRD、H2-TPR、O2-TPD和甲烷气-固反应等手段,进行了Pr-Zr固溶体制备最优路径的探索与其氧化性能的研究。结... 通过共沉淀法制备了Pr0.7Zr0.3O2-δ复合氧化物氧载体,考察了制备温度、老化时间、pH以及母液浓度对Pr-Zr固溶体形成的影响,借助XRD、H2-TPR、O2-TPD和甲烷气-固反应等手段,进行了Pr-Zr固溶体制备最优路径的探索与其氧化性能的研究。结果表明:以Pr(NO3)3·6H2O和Zr(NO3)4为前驱盐,沉淀温度20℃、pH=12、800℃焙烧可制得Pr0.7Zr0.3O2-δ完美固溶体,固溶体的形成可增强材料晶格氧的移动性,从而提高其与甲烷的反应活性。 展开更多
关键词 pr-zr固溶体 制备方法 氧载体 甲烷部分氧化
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Pr掺杂Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)用于三效催化(TWC)反应:缺陷性质-活性关系 被引量:1
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作者 张彤 李巧艳 +2 位作者 王小燕 梁美生 莱卓君 《中国环境科学》 EI CAS CSCD 北大核心 2023年第10期5257-5269,共13页
为探究稀土金属掺杂CeZrO_(x)催化剂引发的缺陷结构对汽车尾气污染控制的影响,合成了不同Pr掺杂量的Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)系列催化剂,并对其进行了TWC催化活性评价、耐SO_(2)性能测试和系统性表征,研究Pr掺杂引... 为探究稀土金属掺杂CeZrO_(x)催化剂引发的缺陷结构对汽车尾气污染控制的影响,合成了不同Pr掺杂量的Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)系列催化剂,并对其进行了TWC催化活性评价、耐SO_(2)性能测试和系统性表征,研究Pr掺杂引起的缺陷性质对催化性能的影响.结果表明,Pr掺杂Ni~(Ce-Zr)O_(2)/Al_(2)O_(3)产生两种缺陷:氧空位(O_(v))和晶格扭曲,Pr的掺杂水平控制着缺陷位的类型和浓度.O_(v)在TWC反应中起关键作用.在Pr掺杂的Ni~(Ce_(6)Zr_(4-x)Pr_(x))O_(2)/Al_(2)O_(3)催化剂中,TWC的催化性能显著地依赖于O_(v)浓度,Pr掺杂产生的O_(v)可改善NiO的分散,加速本体氧的迁移和扩散,促进大量活性氧物种的形成,促进CO和HC的吸附和氧化,也可激活和削弱N-O键促进NO的解离.具有最多O_(v)数量的Ni~(Ce6Zr3Pr1)O_(2)/Al_(2)O_(3)在200~600℃时表现出最突出的三效催化性能和较好的抗硫性能,而晶格扭曲对催化性能影响并不大. 展开更多
关键词 Ni~(Ce-Zr-Pr)O_(2) Pr掺杂 氧空位(Ov) 晶格扭曲 构效关系
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Pr/Zr原子比对Pr_(x)Zr_(1−x)O_(2−δ)催化氧化脱硝活性的影响
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作者 龚宥精 何人广 +5 位作者 赵光垒 贾丽娟 高冀芸 王访 段开娇 刘天成 《燃料化学学报(中英文)》 EI CAS CSCD 北大核心 2023年第7期996-1006,共11页
采用溶胶-凝胶法制备了不同Pr/Zr原子比的Pr_(x)Zr_(1−x)O_(2−δ)催化剂用于催化氧化脱硝。结果表明,催化氧化脱硝效率随Pr原子比的增加而先提高后降低;当Pr/Zr原子比为5∶5时,在250°C下,最佳脱硝活性可达94.62%。采用SEM、N_(2)吸... 采用溶胶-凝胶法制备了不同Pr/Zr原子比的Pr_(x)Zr_(1−x)O_(2−δ)催化剂用于催化氧化脱硝。结果表明,催化氧化脱硝效率随Pr原子比的增加而先提高后降低;当Pr/Zr原子比为5∶5时,在250°C下,最佳脱硝活性可达94.62%。采用SEM、N_(2)吸附-脱附、XRD、XPS、H_(2)-TPR和FT-IR对催化剂进行了表征。结果表明,活性最好的催化剂(Pr_(0.5)Zr_(0.5)O_(2−δ))具有“层状”形貌,表面孔隙多,比表面积大,孔体积分别为77.74 m^(2)/g和0.66 cm^(3)/g。此外,随着Pr原子的增加,晶相从c-ZrO_(2)转变为Pr_(2)Zr_(2)O_(7)。XPS和H_(2)-TPR结果表明,表面化学吸附氧和表面Pr^(4+)氧化物增加,Pr原子比的上升有利于产生氧空位(Vӧ),有利于提高催化氧化脱硝效率。FT-IR表征结果表明,Pr_(0.5)Zr_(0.5)O_(2−δ)固溶体具有较高的NO选择性,有利于NO的催化氧化。抗SO_(2)和H_(2)O毒性实验表明,5∶5的Pr/Zr原子比的催化剂具有更好的抗毒性。此外,利用IC分析吸收产物,结果表明,吸收液中的主要产物是NO_(2)^(-)和NO_(3)^(-)。 展开更多
关键词 催化氧化 氮氧化物 Pr_(x)Zr_(1-x)O_(2-δ) Pr/Zr原子比
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Selective oxidation of methane to syngas using Pr_(0.7)Zr_(0.3)O_(2-δ): Stability of oxygen carrier
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作者 杜云鹏 祝星 +2 位作者 王华 魏永刚 李孔斋 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第4期1248-1253,共6页
Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical pro... Pr0.7Zr0.3O2-δ solid solution was prepared by co-precipitation method and used as an oxygen carrier in the selective oxidation of methane to syngas(methane/air redox process). The evolution on the physicochemical properties of Pr0.7Zr0.3O2-δ during the redox process was studied by means of X-ray diffraction(XRD), H2 temperature-programmed reduction(H2-TPR), O2temperature-programmed desorption(O2-TPD), Brunauer-Emmett-Teller(BET) surface area measurement and X-ray photoelectron spectroscopy(XPS) technologies. The results indicated that Pr0.7Zr0.3O2-δ solid solution showed the high activity for the methane conversion to syngas with a high CO selectivity in the range of 83.5%-88.1%. Though Pr-Zr solid solution possessed high thermal stability, lattice oxygen was obviously reduced for the recycled sample due to decreased surface oxygen which promoted oxygen vacancies. The increased oxygen vacancies seemed to enhance the oxygen transfer ability in the redox process and provided sufficient oxygen for the methane selective oxidation, resulting in a satisfactory activity. The problem of hot pot was avoided by comparing fresh, aged and recycle sample in the reaction. 展开更多
关键词 METHANE selective oxidation oxygen carrier pr-zr solid solution SYNGAS STABILITY
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(Ce-Zr-Pr)O_2在三效催化剂中的应用 被引量:7
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作者 袁慎忠 肖彦 +4 位作者 张燕 薛群山 刘毅 鞠文鹏 陈楠 《中国稀土学报》 CAS CSCD 北大核心 2006年第z1期66-68,共3页
采用共沉淀方法制备了(Ce-Zr-Pr)O2样品,利用XRD,BET对样品进行了表征,并将样品用于三效催化剂的制备,利用实验室配气装置模拟尾气条件,对催化剂性能进行了评价。结果表明,(Ce-Zr-Pr)O2具有立方萤石结构,耐热稳定性较好,所制备的催化剂... 采用共沉淀方法制备了(Ce-Zr-Pr)O2样品,利用XRD,BET对样品进行了表征,并将样品用于三效催化剂的制备,利用实验室配气装置模拟尾气条件,对催化剂性能进行了评价。结果表明,(Ce-Zr-Pr)O2具有立方萤石结构,耐热稳定性较好,所制备的催化剂具有更好的氧化还原活性,表现为起燃温度较低,NOx的净化效率较高。 展开更多
关键词 (Ce-Zr-Pr)O2 三效催化剂 稀土
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Zr对P-Fe-B非晶合金晶化形成纳米晶合金的作用 被引量:4
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作者 刘建华 张朋越 +5 位作者 杨丽 谌岩 关颍 张克勤 张静武 张湘义 《功能材料》 EI CAS CSCD 北大核心 2002年第3期260-261,共2页
从非晶合金晶化激活能的角度 ,分析了Pr Fe B非晶合金在退火过程中晶粒粗大的原因 ,揭示了Zr元素在其晶化过程中的作用。结果表明 ,Zr能改变Pr Fe B非晶合金中α Fe相的晶化行为 ,有助于形成尺寸细小的α
关键词 非晶合金 纳米晶合金
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掺杂方式对纳米(Ce-Zr-Pr)O_2/γ-Al_2O_3陶瓷载体涂层性能的影响 被引量:1
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作者 田久英 卢菊生 +1 位作者 吴宏 杜百祥 《高校化学工程学报》 EI CAS CSCD 北大核心 2013年第1期152-158,共7页
采用在拟薄水铝石溶胶中分别掺杂纳米(Ce-Zr-Pr)O2固溶体粉末和前驱体溶胶的方式,制备(Ce-Zr-Pr)O2/γ-Al2O3蜂窝陶瓷载体涂层。并利用XRD、H2-TPR、BET和氧脉冲等手段研究掺杂方式对涂层的晶相结构、还原性能、比表面积和储氧性能的影... 采用在拟薄水铝石溶胶中分别掺杂纳米(Ce-Zr-Pr)O2固溶体粉末和前驱体溶胶的方式,制备(Ce-Zr-Pr)O2/γ-Al2O3蜂窝陶瓷载体涂层。并利用XRD、H2-TPR、BET和氧脉冲等手段研究掺杂方式对涂层的晶相结构、还原性能、比表面积和储氧性能的影响,由SEM照片观察涂层的表面形貌。结果表明,两种掺杂方式制备(Ce-Zr-Pr)O2/γ-Al2O3涂层均具有较好的织构和储氧性能。其中前驱体溶胶掺杂方式制备涂层液的粒径小,分布范围窄,且涂层表面光滑均匀,比表面积和储氧性能较高。(Ce-Zr-Pr)O2/γ-Al2O3蜂窝陶瓷载体涂层负载的单Pd三效催化剂具有低的起燃温度和优异的三效催化转化活性。 展开更多
关键词 掺杂方式 纳米(Ce-Zr-Pr)O2固溶体 蜂窝陶瓷载体 涂层
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Influence of Water Pollution on MIC of Stainless Steel 304L 被引量:1
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作者 LING Yun CHEN Z G GUEMPL P KAESSER M 《Journal of Iron and Steel Research International》 SCIE CAS CSCD 2002年第2期45-48,共4页
Crystallization kinetics of Pr 8Fe 86 x Zr x B 6 ( x =0, 1, 2) amorphous alloys was studied by DTA and XRD methods. The experimental results showed that the crystalline phases of Pr 8Fe 86 B 6 ... Crystallization kinetics of Pr 8Fe 86 x Zr x B 6 ( x =0, 1, 2) amorphous alloys was studied by DTA and XRD methods. The experimental results showed that the crystalline phases of Pr 8Fe 86 B 6 alloy are composed of α Fe phase, Pr 2Fe 23 B 3 and Pr 2Fe 14 B, when crystallization temperature is below 900 ℃. The activation energy of α Fe phase remains relatively constant about 306.09 kJ/mol, as the crystalline fraction of α Fe phase is below 8 %. At the beginning of crystallization, the activation energy of Pr 2Fe 23 B 3 and Pr 2Fe 14 B phases are 510.85 kJ/mol and 725.97 kJ/mol, respectively, and then the activation energy of three phases declines with increasing the crystalline fraction. The crystallization behavior of α Fe and Pr 2Fe 14 B essentially results in the formation of a α Fe/Pr 2Fe 14 B composite microstructure with a coarse grain size in annealed Pr 8Fe 86 B 6 alloy, which is attributed to a difficult nucleation and an easy growth for both the α Fe and Pr 2Fe 14 B in the alloy. Zr can be used to change the crystallization behavior of the α Fe phase in Pr Fe B amorphous alloy, which is helpful to the formation of the α Fe/Pr 2Fe 14 B nanocomposite microstructure with a fine grain size for the α Fe phase in the alloy. 展开更多
关键词 Pr 8Fe86-x Zr xB 6 amorphous alloy crystallization kinetics activation energy
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Effects of Zr on crystallization kinetics of Pr-Fe-B amorphous alloys 被引量:1
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作者 刘建华 李伟 +1 位作者 谌岩 关颖 《中国有色金属学会会刊:英文版》 CSCD 2002年第3期466-469,共4页
The effects of Zr on crystallization kinetics of Pr Fe B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr 8Fe 86- x Zr x B 6 ( x =0, 1, 2) amorphous alloys, the final crystalliz... The effects of Zr on crystallization kinetics of Pr Fe B amorphous alloys have been investigated by DTA and XRD methods. It was found that for Pr 8Fe 86- x Zr x B 6 ( x =0, 1, 2) amorphous alloys, the final crystallized mixture is α Fe and Pr 2Fe 14 B, and the metastable Pr 2Fe 23 B 3 phase occurs during crystallization of Pr 8Fe 86 B 6 amorphous alloy, not during crystallization of Pr 8Fe 86- x Zr x B 6( x =1, 2) amorphous alloys. By analyzing the activation energy of crystallization, the formation of an α Fe/Pr 2Fe 14 B composite microstructure with a coarse grain size in annealed Pr 8Fe 86 B 6 alloy, is attributed to a difficult nucleation and an easy growth for both the α Fe and Pr 2Fe 14 B in the alloy. The addition of Zr can be used to change the crystallization behavior of the α Fe phase in Pr Fe B amorphous alloy, which is helpful to reduce the grain size for the α Fe phase. 展开更多
关键词 非晶合金 结晶 动力学 Pr-Fe-B合金
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Influences of (Ce-Zr-La-Pr)O Contents on Three-Way Catalyst Performances 被引量:1
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作者 张爱敏 宁平 马丽萍 《Journal of Rare Earths》 SCIE EI CAS CSCD 2005年第S1期65-69,共5页
A series of catalysts with (Ce-Zr-La-Pr)O contents range from 0 to 50% in coating and single-palladium loads on substrates were prepared to study effects of (Ce-Zr-La-Pr)O contents on catalytic activities and durabili... A series of catalysts with (Ce-Zr-La-Pr)O contents range from 0 to 50% in coating and single-palladium loads on substrates were prepared to study effects of (Ce-Zr-La-Pr)O contents on catalytic activities and durability by contrasting the characteristics of light-off, A/F and catalytic conversions of the fresh catalysts with that of the aged catalysts. The results show that (Ce-Zr-La-Pr)O can enhance the catalysts light-off characteristics, widen A/F windows and increase catalytic conversions at a certain extent through optimizing physical structural and chemical property of the mixed coating. However, (Ce-Zr-La-Pr)O contents influence greatly on the catalysts activities and durability, and the catalysts with contents ranging from 10% to 30% exhibited better integrative properties in all samples, and 10% was the optical content to make the catalyst performance highest in this thesis. It is indicated that an suitable content of (Ce-Zr-La-Pr)O plays an important role in assisting catalysis, enhancing durability and increasing oxygen storage capability. 展开更多
关键词 (Ce-Zr-La-Pr)O mixed oxide three-way catalyst catalytic activity durability rare earths
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Influences of Platinum Precursors and Solution Acidities on REO-Based Catalysts Performances
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作者 张爱敏 宁平 《Journal of Rare Earths》 SCIE EI CAS CSCD 2006年第z2期39-41,共3页
Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as P... Important effects exist between precious metals and rare earths oxides in three-way catalyst, especially the coordinated effects. These effects were studied by using H2PtCl6, Pt(NH3)2(NO2)2 and Pt(OH)2(C2H5ONH2)2 as Pt precursors, and the mixed oxide of (Ce-Zr-La-Pr)O as base material to prepare a series of catalysts, and their performances of the catalysts were studied by TPR and CO pulse titration technologies. The results shown that Pt precursors and their solutions pH values influenced the oxygen storage capabilities, the active metal distribution degrees of the catalysts obviously, and every catalyst prepared by different precursors had an optimal pH values. It indicates that the active metals precursors and their solutions acidities have outstanding influences on the catalysts performances for the mutual effects existing between the active metals and the Rare Earth metal oxides, which results from the mate groups of the precursors and the solution acidity. 展开更多
关键词 Pt precursors (Ce-Zr-La-Pr)O mixed oxide three-way catalyst catalyst performances solution acidity rare earths
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Effect of Zr on Microstructure and Magnetic Properties of Nanocrystalline (Nd, Pr)FeB/α-Fe Composite Alloys
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作者 刘锦云 刘颖 +2 位作者 王克强 查五生 涂铭旌 《Journal of Rare Earths》 SCIE EI CAS CSCD 2004年第S1期108-111,共4页
For nanophase (Nd, Pr)FeB/α-Fe composite alloys were prepared by melt spinning, the appreciable addition of Zr reduces their average grain size. Observed by atom force microscopy (AFM), the average grain diameter of ... For nanophase (Nd, Pr)FeB/α-Fe composite alloys were prepared by melt spinning, the appreciable addition of Zr reduces their average grain size. Observed by atom force microscopy (AFM), the average grain diameter of crystallized ribbons on their free surface, reduces from 175 nm of Zr-free alloy to 79 nm of Zr-1at%, by about 55%. If the concentration exceeds 1%, the effects of Zr on fining grain size are evidently weakened. The average grain size on free surface of Zr-1.5at% is 72 nm. With the addition of 1at% Zn, the bonded magnets has the best combination of properties: B_r=0.675 T, H_(ci)=616 kA·m^(-1), (BH)_(max)=77 kJ·m^(-3). Below 1at%, the coarser grains lead to a lower magnetic property. Beyond 1at%, the layer of Zr-rich intergranular phase will thicken, which results in weakening of the exchange coupling among adjacent grains, and then causes degrading of magnetic properties of magnets. 展开更多
关键词 metal materials Pr-based permanent magnets nanocrystalline composite Zr dopant melt spining (microstructure ) magnetic properties rare earths
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