纳米CeO2/聚苯乙烯杂化材料的制备及表征

用反相胶束微乳液法制备了纳米CeO2/聚苯乙烯杂化材料 .XRD分析表明,纳米CeO2/聚苯乙烯杂化材料中,CeO2是无定形粒子.XPS分析表明,杂化材料并非简单的物理混合,CeO2纳米粒子与有机物之间存在着一定强度的化学键.FTIR分析表明,CeO2粒子的吸收存在蓝移现象.     

钕, 铈掺杂的正极材料尖晶石型LiMn2O4的制备及性能

通过掺杂不同含量的Ｎｄ,Ｃｅ制备ＬｉＭｎ２－ｘＲＥｘＯ４（ＲＥ＝Ｃｅ,Ｎｄ;ｘ＝０,０．０５,０．１,０．１５,０．２）锂离子电池正极材料,研究稀土元素拓杂对尖晶石ＬｉＭｎ２Ｏ４正极材料电化学性质的影响。掺杂Ｎｄ,Ｃｅ后ＬｉＭｎ２Ｏ４正极材料更适合于锂离子的嵌入和脱出,电池的循环性能提高,但充放电容量随掺杂量的增加而下降。Ｘ射线光电子能谱分析表明掺杂Ｎｄ,Ｃｅ的ＬｉＭｎ２Ｏ４正极材料,其Ｍｎ＾４＋     

纳米复合固体超强酸SO42-/CoFe2O4的制备和表征

采用纳米化学制备技术合成了新型的纳米复合固体超强酸催化剂ＳＯ４＾２－／ＣｏＦｅ２Ｏ４。用ＸＲＤ、ＴＥＭ、ＸＰＳ、红外光谱和比表面测定等技术研究了该催化剂的结构形态,结果表明：所研制的ＳＯ４＾２－／ＣｏＦｅ２Ｏ４２催化剂为晶态纳米粒子（〈５０ｎｍ）,比表面积很大（１５７ｍ＾２．ｇ＾－１）,ＳＯ４＾２－与氧化物的金属离子呈无机齿螯合状配位化合物的结合形式。以乙酸乙酯合成为模型反应考究了该催化剂的催化活     

CuO／CeO_2／γ－Al_2O_3催化剂的结构及氧物种

应用ＸＲＤ、ＥＳＲ及ＸＰＳ方法研究了ＣｕＯ／ＣｅＯ２／γ－Ａｌ２Ｏ３催化剂的体相及表面结构，并对催化剂表面氧物种进行了表征．实验结果表明，ＣｅＯ２使Ｃｕ２＋还原为低价钢离子和增加钢化合物的分散性．催化剂中ＣｅＯ２含量高时，表面有Ｏ２－和Ｏ－物种，而ＣｅＯ２含量低时，只有Ｏ２－物种．     

NaCl和B2O3在修饰FeOχ催化剂中的协同作用

应用连续催化反应，ＸＰＳ，ＸＲＤ，Ｈ２－ＴＰＲ，Ｏ２－ＴＰＤ和Ｉｎ－ｓｉｔｕ Ｍｏｓｓｂａｕｅｒ谱等方法表征了一系列组成不同的ＮａＣｌ／Ｂ２Ｏ３／Ｆｅ２Ｏ３催化剂。结果表明ＮａＣｌ与Ｂ２Ｏ３在修饰ＦｅＯｘ催化剂上存在明显的协同作用，Ｂ２Ｏ３调变了ＦｅＯｘ的还原能力，ＮａＣｌ修饰了Ｂ２Ｏ３／ＦｅＯｘ使之具有很高的还原速度与晶格氧气化速度。催化剂的催化性能同这种协同作用密切相关。     

CuO／CeO2和CuO／Al2O3催化剂的催化性能

本文以ＣＯ氧化为模式反应考察了ＣｅＯ２和Ａｌ２Ｏ３负载氧化铜催化剂的氧化活性，运用ＸＲＤ和ＴＰＲ技术研究了催化剂的还原性能和物相结构，结果表明：载体性质对负载ＣｕＯ催化剂的ＣＯ氧化活性有很大影响，ＣｕＯ／ＣｅＯ２催化剂活性明显高于ＣｕＯ／Ａｌ２Ｏ３催化剂．催化剂的还原特性随载体不同而不同．同时发现，热处理对催化剂铜物种的存在形式，晶粒大小、还原特性及其催化活性有明显影响，ＣｕＯ／Ａｌ２Ｏ３催化剂活性下降的主要因素是生成了活性较低的ＣｕＡｌ２Ｏ４相，而ＣｕＯ／ＣｅＯ２催化剂活性下降是由于ＣｕＯ和ＣｅＯ２发生烧结，晶粒变大     

溶胶-凝胶法合成聚甲基丙烯酸甲酯/二氧化钛-二氧化硅杂化聚合物材料

通过溶胶 凝胶过程合成了有机聚合物链段与无机相间有共价键存在的Ｐ（ＭＭＡ ＭＳＭＡ）／ＴｉＯ２ ＳｉＯ２杂化聚合物材料．溶剂抽提结果表明杂化材料体系中凝胶的含量很高．通过ＦＴＩＲ测试对材料进行了结构分析，并且由ＴＧＡ、ＤＳＣ测试分别分析了杂化材料体系中无机组份总量以及Ｔｉ（ＯＣ４Ｈ９）４的含量对材料性能的影响．     

纳米复合固体超强酸SO42-/CoFe2O4的制备和表征

采用纳米化学制备技术合成了新型的纳米复合团体超强酸催化剂ＳＯ４２－／ＣｏＦｅ２Ｏ４。用ＸＲＤ、ＴＥＭ、ＸＰＳ、红 外光谱和比表面测定等技术研究了该催化剂的结构形态,结果表明：所研制的ＳＯ４２－／ＣｏＦｅ２Ｏ４催化剂为晶态纳 米粒子（＜ ５０ｎｍ）,比表面积很大（１５７ｍ２· ｇ－１）,ＳＯ４２－与氧化物的金属离子呈无机双齿螯合状配位化合物的结 合形式。以乙酸乙酯合成为模型反应考察了该催化剂的催化活性,比较了酸性和酸强度,推断出该催化剂的酸 强度Ｈ０＜－１４．５。     

Triton X－100／C_（10）H_（21）OH／H_2O体系层状液晶中水溶性超微粒子材料Na_2C_2O_4的制备

利用溶剂在层状液晶中的渗透性和层状液晶中溶剂层厚度的限定性，在ＴｒｉｔｏｎＸ－１００／Ｃ_（１０）Ｈ_（２１）ＯＨ／Ｈ_２Ｏ体系层状液晶中，以饱和Ｎａ_２Ｃ_２Ｏ_４水溶液代替组分水制备水溶性超微粒子材料Ｎａ_２Ｃ_２Ｏ_４，平均粒径约为６ｎｍ．     

含Ce的水热体系中结构稳定性及变价现象

利用ＸＲＤ、ＩＲ及ＸＰＳ谱研究了含Ｃｅ的水热体系中产物及其经过各种后处理的样品结构稳定性及Ｃｅ离子的价态变化。结果表明，不同的原料导致Ｃｅ离子稳定于不同的价态，如直接形成包括纳米晶在内的ＣｅＯ２及一新相ＣｅＯＨＣＯ３，样品ＣｅＯＨＣＯ３经２ＧＰａ的冷压处理未发生结构转变，经高温焙烧处理得到具有高结晶度的棕红色的ＣｅＯ２，当初始原料为Ｃｅ２（ＳＯ４）３和Ｃｅ（ＮＯ３）３时，产物为ＣｅＯ２；而当初始原     

棒状CeO_2负载Pt催化剂的合成及其电化学性能研究

通过水热法合成棒状纳米Ce O2(Ce O2-R),并将Pt纳米颗粒负载于Ce O2表面,制得甲醇燃料电池的阳极催化剂Pt/Ce O2-R.通过结构与形貌表征,结果表明,Pt/Ce O2-R中Ce O2的暴露晶面为(111)和(002)晶面,改变了Pt周围的电子结构,进而降低了Pt-COads的键能,释放出更多的活性位.另外,Pt纳米颗粒在Ce O2-R表面分散更均匀.利用电化学工作站测试阳极催化剂Pt/Ce O2-R在酸性溶液中的电化学性能,证明Pt/Ce O2-R催化剂的甲醇电氧化性能与抗CO毒害能力较颗粒状Ce O2负载Pt催化剂(Pt/Ce O2-P)都有很大的提高,证明Ce O2-R作为Pt纳米颗粒的载体用于直接甲醇燃料电池的阳极反应具有发展潜力.     

A Highly Reactive and Sinter-Resistant Catalytic System Based on Platinum Nanoparticles Embedded in the Inner Surfaces of CeO(2) Hollow Fibers

Ceria (CeO(2) ) hollow fibers with Pt nanoparticles (Pt?NPs) embedded in their inner surfaces were prepared by sequentially depositing Pt?NPs and CeO(2) sheaths on electrospun fibers of polystyrene, followed by calcination in air at 400?°C. Despite a relatively low Pt loading in this system, the turnover frequency for CO oxidation was 2-3 orders of magnitude higher than those of other systems, and the reactivity was also stable up to 700?°C.     

Electron transfer behavior and water photodecomposition ability of calcined material from a cerium-S-phenylene-O-holmium-O-phenylene-S hybrid copolymer

Calcination of a cerium-S-phenylene-O-holmium-O-phenylene-S hybrid copolymer under a vacuum gave cerium oxide-carbon cluster-holmium oxide composite material. The material calcined at 600 degrees C loaded with Pt particles could decompose water to H2 and O2 with a H2/O2 ratio of 2 under visible light irradiation. ESR spectral examinations of the calcined materials revealed the possibility of a two-step electron transfer in the process of CeO2 --> carbon cluster --> Ho2O3 --> Pt with an oxidation site at CeO2 particles and a reduction site at Pt particles.     

CeO2 nanoparticles/graphene nanocomposite-based high performance supercapacitor

CeO(2) nanoparticles/graphene nanocomposite is fabricated by depositing CeO(2) nanoparticles onto three-dimensional graphene material and its supercapacitor performance is further investigated. The nanocomposite shows a high specific capacitance and power density, demonstrating a strong synergistic effect possibly contributed from improved conductivity of CeO(2) and better utilization of graphene.     

CeO2@Au核壳结构纳米粒子的合成与性质研究

采用沉淀法制备了球形CeO2纳米粒子,将其作为核粒子溶液,然后向其中滴加四氯合金酸溶液,在CeO2胶体表面利用柠檬酸钠还原[AuCl4]-离子,得到了CeO2@Au核壳结构纳米粒子。TEM分析表明,CeO2纳米粒子分散效果好,粒径为5 nm;CeO2@Au核壳粒子为球形,无团聚,平均粒径为15 nm。XRD分析表明,CeO2@Au核壳粒子为晶型结构,属于立方晶系,CeO2空间群为O5H-FM3M,Au的空间群为Fm-3m。UV-vis分析发现,CeO2@Au核壳粒子在300和520 nm处呈现出两个比较强的吸收峰,分别对应于CeO2胶体溶液的吸收峰和金粒子的表面等离子共振吸收峰。EDS分析了核壳结构CeO2@Au纳米粒子中存在Ce,O和Au 3种元素。XPS分析表明,Ce3d3/2和Au4f电子结合能与标准结合能相比发生了变化,说明CeO2与Au之间存在着相互作用。     

Production of complex cerium-aluminum oxides using an atmospheric pressure plasma torch

Ceria-alumina particles of a wide variety of structures, from micrometer-sized hollow spheres to nanoparticles, were produced from aerosols of different natures, but all derived from nitrate salts passed through a low power (<1000 W) atmospheric pressure plasma torch. The amount of water present with the nitrate salts was found to significantly affect the morphology of the resulting material. A model was proposed that explains the mechanism in which water acts as a blowing agent to create hollow metal oxide spheres that then shatter to form metal oxide nanoparticles. Further examination of the nanoparticles revealed that they display a core/shell morphology in which the core material is crystalline CeO2 and the shell material is amorphous Al2O3. These unique core/shell materials are interesting candidates for catalyst support materials with high thermal durability. In addition, experiments have shown that the nanoparticles can be readily converted into CeAlO3 perovskite.     

Chemoselective hydrogenation catalysts: Pt on mesostructured CeO2 nanoparticles embedded within ultrathin layers of SiO2 binder

Pt on mesostructured CeO(2) nanoparticles embedded within ultrathin layers of highly structured SiO(2) binder shows highest activity reported with 80% selectivity for the chemoselective hydrogenation of crotonaldehyde. Characterization by transmission electron microscopy (TEM), CO adsorption, and X-ray photoelectron spectroscopy (XPS) show the presence of small Pt metal particles, preferentially located on CeO(2) (70%) together with the formation of Pt-CeO(2-x) sites at the interface between Pt and CeO(2) (4 nm) nanoparticles. These sites are able to polarize the carbonyl group and facilitate the selective hydrogenation of this with respect to the double bond.     

Synthesis, characterization and computational study of nitrogen-doped CeO2 nanoparticles with visible-light activity

Nitrogen-doped CeO2 nanoparticles were synthesized through a wet-chemical route. Nitrogen has been successfully incorporated into CeO2 nanoparticles and the nitrogen-doping level was also successfully controlled. The optical properties due to the different N-doping levels in CeO2 nanoparticles were characterized by UV-Vis diffuse reflectance spectroscopy (DRS), which showed a visible-light absorbance shift. The resulting nanoparticles show enhanced visible-light sensitivity and photocatalytic activity compared to undoped CeO2 nanoparticles. DFT calculations were performed to explore the effect of nitrogen doping versus oxygen vacancies. The calculations show that the change of the electronic structure upon N-doping CeO2 is quite different from that of N-doped TiO2, which has been studied extensively.     

多金核二氧化铈空心球用于硝基苯酚催化加氢

催化剂的微观结构在催化还原反应、有机物氧化反应及有机物转化反应中起着关键作用。本文利用无模板方法合成了多金核中空二氧化铈微球催化剂。将制备好的二氧化铈中空微球浸渍到一定浓度的氯金酸溶液中,然后多次洗涤除去表面吸附的氯金酸离子,最后通过硼氢化钠还原制成中空氧化铈微球包覆的多金核的核壳结构催化剂。将该核壳结构材料用于硝基苯酚加氢反应与金纳米粒子及氧化铈微球相比,多金核中空二氧化铈核壳结构表现出优越的活性和稳定性。通过这种浸渍洗涤再还原的简单方法合成的多金核二氧化铈催化剂有望应用于生物医药和能源环境等领域。