Fe3+改性纳米ZnO光催化降解壬基酚聚氧乙烯醚

采用氨浸法制备了不同Fe3 含量的Fe3 /ZnO光催化剂,并用X射线衍射、N2吸附、X射线光电子能谱和紫外-可见漫反射光谱对纳米Fe3 /ZnO进行了表征.以壬基酚聚氧乙烯醚(NPE-10)为模型污染物,分别在紫外光和可见光下考察了纳米Fe3 /ZnO的光催化活性.结果表明,该方法能成功地将Fe掺杂到ZnO晶体上,且随着Fe3 添加量的增加,ZnO的晶粒尺寸逐渐减小,比表面积逐渐增大.与纳米ZnO样品相比,Fe3 /ZnO中Fe2p结合能减小,而Zn2p和O1s结合能增大,ZnO表面的羟基氧和吸附氧含量增加,光催化活性提高.当Fe3 的添加量大于0.5%时,Fe3 /ZnO样品的吸收光谱发生红移,在可见光区出现吸收.光催化降解结果显示,0.5?3 /ZnO样品的光催化活性最高,在紫外光和可见光照射3h后对NPE-10的降解率分别比纯ZnO提高18%和69%.     

聚乙烯醇纤维金属配合物的合成和表征

以聚乙烯醇纤维(PVA)为配体原料,分别与FeCl3、NiCl2、CuCl2和Pb(Ac)2反应,制备了宏观上仍保持原纤维形态的PVA Fe(Ⅲ)、PVA Ni(Ⅱ)、PVA Cu(Ⅱ)、PVA Pb(Ⅱ)纤维配合物(用PVA M表示).用红外光谱仪分别对PVA和4种配合物在4000～400cm-1范围进行傅立叶变换红外光谱测量,对各PVA M的FTIR主要吸收峰做了经验归属,并与PVA的相应吸收峰做对比分析,结果表明,与金属离子形成配合物后,PVA分子中O—H氢键缔合状态被破坏,向高波数位移了65～86cm-1,PVA中的羟基氧与金属离子发生配位作用.PVA Fe(Ⅲ)的XPS显示,PVA中O1s只出现532.5eV单峰,而PVA Fe(Ⅲ)中O1s分裂为531.4eV和532.3eV两个峰,且Fe2p只有一个峰710.9eV,比FeCl3的结合能值711.2eV下降,说明OH氧与Fe3+形成配位键.     

纳米Fe2O3/高氯酸铵复合粒子的制备及其热分解性能研究

用溶剂-非溶剂法制备了纳米Fe2O3／高氯酸铵(AP)复合粒子,并用TEM,SEM,XRD和ICP对其进行了表征．为了研究纳米复合粒子中纳米Fe2O3对AP热分解的催化性能,将相同比例的微米Fe2O3和纳米Fe2O3与AP分别简单混合后作对比,并用DTA对三种样品进行了热分析．结果表明,三种样品中的Fe2O3粒子都能催化AP的热分解;但纳米Fe2O3粒子的催化性能优于微米Fe2O3粒子,纳米Fe2O3／AP复合粒子中纳米Fe2O3对AP的催化性能优于纳米Fe2O3与AP简单混合物．与纳米Fe2O3与AP简单混合的样品相比,纳米复合粒子中的AP高温分解峰温降低20．1℃,低温分解峰几乎消失,表观分解热由850．2J／g提高到1080．8J／g．证明纳米Fe2O3与AP的复合处理能显著提高纳米Fe2O3对AP热分解的催化性能．并用不同样品中AP热分解的动力学参数对所得结果进行了理论分析．     

超级铝热剂Al/Fe2O3的制备、表征及对环三亚甲基三硝胺热分解的影响

采用水热法制备了中空短棒状纳米Fe2O3,并用超声分散法将其与纳米Al颗粒复合为单金属氧化基超级铝热剂.利用X射线粉末衍射(XRD)、傅里叶变换红外(FTIR)光谱、扫描电镜及能量散射光谱仪(SEM-EDS)对样品进行表征.并运用差示扫描量热法(DSC)对比研究了超级铝热剂Al/Fe2O3、Al粉和纳米Fe2O3对环三亚甲基三硝胺(RDX)热分解特性的影响.结果表明:超级铝热剂的加入改变了RDX的热分解过程,并加剧了RDX的二次气相反应;随着超级铝热剂含量的增加,RDX的分解峰峰形发生了明显的改变;Al/Fe2O3、Al粉和Fe2O3对RDX热分解的作用主要表现为二次分解峰逐渐明显且峰温降低.     

C(2×2)S/Fe(001)吸附体系的SCF-Xa-MS研究

采用SCF-X_α-MS方法, 对于C(2×2)S/Fe(001)吸附体系, 选择Fe_5S和Fe_9S两种原子簇模型, 研究了该吸附体系的电子结构、吸附成键特征及其相互作用图象。结果表明, S吸附于Fe(001)单晶表面具有较强的定域性质, S原子与底物Fe原子之间的吸附相互作用主要表现为S(3p)-Fe(4s,3d)之间的轨道相互作用。通过对表面吸附键长的优化, 其结果与X.S.Zhang等的ARPEFS的实验结果一致。     

C(2×2)S/Fe(001)吸附体系的SCF-X_α-MS研究

采用SCF-X_α-MS方法,对于C(2×2)S/Fe(001)吸附体系,选择Fe_5S和Fe_9S两种原子簇模型,研究了该吸附体系的电子结构、吸附成键特征及其相互作用图象。结果表明,S吸附于Fe(001)单晶表面具有较强的定域性质,S原子与底物Fe原子之间的吸附相互作用主要表现为S(3p)-Fe(4s,3d)之间的轨道相互作用。通过对表面吸附键长的优化,其结果与X.S.Zhang等的ARPEFS的实验结果一致。     

复合氧化物LaMn1-xFexO3(x=0-1)的XPS研究

用XPS方法研究了具有ABO3结构的LaMn1-xFexO3（x＝0－1）氧化物的氧化还原性能、表面组成和吸附氧种．样品经还原和再氧化处理后，Mn2p和Fe2p结合能的变化对Fe和Mn之间发生的氧化还原提供了明显的证据．可表示如下：Me4＋＋Fe（3－δ）→Mn（4－δ）＋＋Fe3＋通过计算机用三种氧物种（OⅠ，OⅡ和OⅢ）对O1s峰进行拟合，确定了每种氧物种的状态．同时，以氧物种含量随还原、再氧化的变化，确定了发生在表面上的氧化还原反应同OⅠ和OⅡ吸附氧物种有关．在此基础上，对吸附位与氧之间的电子转移过程进行了讨论．     

纳米Fe2O3的制备及其对高氯酸铵热分解的催化性能

 用两相体系方法制备了纳米Fe2O3，并用X射线衍射、红外光谱和粒度分析对其结构进行了表征．结果表明，当有机溶胶的pH＝6，油酸与Fe3＋的摩尔比为1∶3．5时，Fe（OH）3在油相中的萃取率可高达90％，将有机溶胶在120℃回流8h后可得到非晶态、窄粒度分布的纳米Fe2O3粒子，其粒径在12nm左右．分别采用恒容燃烧热和差热分析研究了纳米Fe2O3对高氯酸铵热分解的催化性能．结果表明，在模拟固体推进剂中分别加入4．7％微米Fe2O3和4．7％纳米Fe2O3后，恒容燃烧热分别提高了2350．84和5095．70J／g．在高氯酸铵中加入5％微米Fe2O3可使高氯酸铵两个放热峰的出现分别提前1．10和62．25℃，而加入5％纳米Fe2O3时分别提前61．89和118．82℃，这说明纳米Fe2O3的催化活性优于微米Fe2O3．     

铁氰化镨修饰的电化学传感器的研制及其对半胱氨酸的测定

采用循环伏安法在PrCl3+K3Fe(CN)6溶液中于石墨电极表面电沉积铁氰化镨(PrHCF)薄膜,制备PrHCF修饰电极。对该修饰电极电化学的行为进行分析,包括扫描速度、K+浓度以及阴、阳离子对膜电极的影响。同时,以红外和XPS对膜进行了表征,IR谱图中氰基的伸缩振动峰证明了膜的存在;而XPS谱图中Fe2p1/2和Fe2p3/2能级的分裂说明了在成膜过程中Fe的价态发生变化,据此提出了可能的电聚合机理。同时,此修饰电极对半胱氨酸具有电催化氧化活性,并对其响应进行了研究。     

Fe原子活化乙烷的微观反应机理

本文采用密度泛函理论B3LYP方法在6-311 G(d,p)基组水平上研究了Fe原子催化乙烷反应的微观反应机理,优化了反应过程中各反应物、中间体、过渡态和产物的构型,并在同一水平上计算了反应中各驻点的振动频率,运用自然键轨道理论(NBO)方法分析了各物质的成键情况和轨道间相互作用。Fe原子对乙烷的活化过程可分为C-C键活化及C-H键活化,分别释放出CH4和H2。     

Investigation of the Fe K-edge XANES spectra from Fe(1-x)Ga(x)SbO4: local versus nonlocal excitations

The Fe K-edge X-ray absorption near-edge (XANES) spectra from Fe(1-x)Ga(x)SbO(4), having a rutile-like structure, have been investigated. Similar to the Ti K-edge XANES spectrum from TiO(2) (rutile), the low-energy pre-edge region observed in the Fe K-edge spectra is too broad to be representative of only a local, quadrupolar 1s → 3d excitation. The broadness of this peak results from the presence of a nonlocal transition, referred to as an intersite hybrid, which involves the excitation of 1s electrons to unoccupied 3d states of a next-nearest-neighbor Fe atom. (These 3d states overlap Fe 4p states of the absorbing atom through O 2p states.) With increasing Ga concentration, the intensity of the intersite hybrid peak decreases because of a deficiency of unoccupied next-nearest-neighbor 3d states. This observation provides important information on how the peak intensities of these nonlocal excitations are affected by substitution of the constituent elements.     

Spectroscopic investigations of Fe2+ complexation on nontronite clay

Diffuse reflectance (visible) and attenuated total internal reflection Fourier-transform infrared (ATR-FTIR) spectroscopies were used to examine a colloidal nontronite clay in the presence of Fe2+(aq). pH-dependent changes are observed in both types of spectra. In the visible region, a broad feature at approximately 750 nm appears as the pH is raised to circumneutral values. This absorbance band overlaps with a portion of the spectrum of the chemically reduced clay which is dominated by an intervalence charge-transfer transition between Fe2+ and Fe3+ within the mineral structure. The similarities between these spectra suggest that Fe2+(aq) adsorbs to the clay in such a way that it can undergo charge transfer with structural Fe3+ within the clay. ATR-FTIR spectra at pH 5-8 reveal a transformation in the Si-O stretching region between pH 6 and pH 7 with a shift of the component peaks to lower frequency. Taken together, these spectroscopic studies indicate that Fe2+ forms an inner-sphere complex with the clay at higher pH values. The pH threshold for these observed changes in physical and electronic structure is in good agreement with the point of zero charge (pzc) of the hydroxyl groups on the edge surfaces of the clay, suggesting that complexation of Fe2+ to deprotonated edge sites leads to the observed spectroscopic features.     

Investigation of multiplet splitting of Fe 2p XPS spectra and bonding in iron compounds

Ferrous (Fe²⁺) and ferric (Fe³⁺) compounds were investigated by XPS to determine the usefulness of calculated multiplet peaks to fit high‐resolution iron 2p_3/2 spectra from high‐spin compounds. The multiplets were found to fit most spectra well, particularly when contributions attributed to surface peaks and shake‐up satellites were included. This information was useful for fitting of the complex Fe 2p_3/2 spectra for Fe₃O₄ where both Fe²⁺ and Fe³⁺ species are present. It was found that as the ionic bond character of the iron —ligand bond increased, the binding energy associated with either the ferrous or ferric 2p_3/2 photoelectron peak also increased. This was determined to be due to the decrease in shielding of the iron cation by the more increasingly electronegative ligands. It was also observed that the difference in energy between a high‐spin iron 2p_3/2 peak and its corresponding shake‐up satellite peak increased as the electronegativity of the ligand increased. The extrinsic loss spectra for ion oxides are also reported; these are as characteristic of each species as are the photoelectron peaks. Copyright © 2004 John Wiley & Sons, Ltd.     

Investigation of Spectra（NMR,Mass）of Some Fe3S3Cluster Compounds

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Fe_3O_4/Au composite nano-particles and their optical properties

The colloid gold and magnetic particle modified with various chemical groups have been widely used in the areas of biomedical and molecular biology[1―6]. Therefore, a great deal of attention has been given to the preparation and application of colloid go…     

X-ray induced damage in DNA monitored by X-ray photoelectron spectroscopy

In this work, the chemical changes in calf thymus DNA samples were analyzed by X-ray photoelectron spectroscopy (XPS). The DNA samples were irradiated for over 5 h and spectra were taken repeatedly every 30 min. In this approach the X-ray beam both damages and probes the samples. In most cases, XPS spectra have complex shapes due to contributions of C, N, and O atoms bonded at several different sites. We show that from a comparative analysis of the modification in XPS line shapes of the C 1s, O 1s, N 1s, and P 2p peaks, one can gain insight into a number of reaction pathways leading to radiation damage to DNA.     

Studies on optical absorption and structural properties of Fe doped CdS quantum dots

Fe doped CdS quantum dots have been prepared using simple precursors by chemical precipitation technique. Fe doped CdS quantum dots have been synthesized by mixing cadmium nitrate, sodium sulfide and adding Fe under suitable conditions. X-ray diffraction analysis reveals that undoped and Fe doped CdS crystallizes in hexagonal structure. The lattice constants of Fe doped CdS nanoparticles decreased slightly with incorporation of Fe and no secondary phase was observed. The average grain size of the nanoparticles is found to lie in the range of 2.8–4.2 nm. HRTEM results show that undoped and 3.75% Fe doped CdS nanoparticles exhibit a uniform size distribution and average size of the nanoparticles is about 2–3 nm. Raman spectra show that 1LO and 2LO peaks of the Fe doped CdS samples are slightly red shifted compared with those of undoped CdS. Optical absorption spectra of Fe doped CdS nanoparticles exhibited red shift.     

Ultrafast hybridization screening in Fe3+ aqueous solution

We report here on the electron binding energies and ultrafast electronic relaxation of the Fe(3+)(aq) complex in FeCl(3) aqueous solution as measured by soft X-ray photoelectron (PE) spectroscopy from a vacuum liquid microjet. Covalent mixing between the 3d valence orbitals of the iron cation and the molecular orbitals of water in the ground-state solution is directly revealed by spectroscopy of the highest partially occupied molecular orbitals. Valence PE spectra, obtained for photon energies near the iron 2p absorption edge, exhibit large resonant enhancements. These resonant PE features identify 3d-O2p transient hybridization between iron and water-derived orbitals and are an indication of charge transfer within the electronically excited Fe(3+)(aq)* complex. Charge transfer from water to iron is also revealed by the 2p core-level PE spectrum, and the asymmetric peak shape additionally identifies the characteristic multiplet interactions in the 2p core-hole state. The electronic structure of water molecules in the first hydration shell is selectively probed by Auger decay from water molecules, at excitation energies well below the O1s absorption edge of neat water. These experiments lay the groundwork for establishing resonant PE spectroscopy for the study of electronic-structure dynamics in the large family of transition metal (aqueous) solutions.     

Second chemiluminescence behavior of Fe2+, Fe3+ and Cr3+ in the luminal-KMnO4 system.

A novel flow injection chemiluminescence (CL) method has been developed for the determination of three metal ions, namely Fe2+, Fe3+ and Cr3+, based on the second CL (SCL) signal of the mixture of luminal with KMnO4 in a sodium hydroxide medium by the catalysis of Fe2+, Fe3+ or Cr3+. The possible CL mechanism of the systems, the influencing factors, and the optimum conditions for the reactions were investigated based upon the kinetic curve of the CL reaction, CL spectra, UV-visible spectra and some other experiments. Under the optimum conditions, the SCL intensity was directly proportional to the concentration of these metal ions in solution in the range of 0.10 - 100.00 mg l(-1) for Fe(2+), 0.50 - 7.50 and 7.50 - 200.00 mg l(-1) for Fe3+, 0.01 - 0.25 and 0.25 - 10.00 mg l(-1) for Cr3+. The detection limits (3 sigma/s) were 9.87 x 10(-6) g l(-1), 2.71 x 10(-6) g l(-1) and 5.25 x 10(-7) g l(-1) for Fe2+, Fe3+ and Cr3+, respectively.     

铁助剂对Rh-Mn-Li/SiO2催化剂表面上的CO脱附和CO加氢行为的影响

 采用一氧化碳程序升温脱附（CO－TPD）和吸附的一氧化碳加氢程序升温表面反应（TPSR）考察了Fe助剂对Rh基催化剂上CO的脱附行为及吸附CO的加氢行为的影响．CO－TPD实验表明，在Rh／SiO2催化剂上CO有三个脱附峰．在Rh－Mn－Li／SiO2中加入0．05％Fe后，高温脱附CO比Rh／SiO2催化剂上相应的CO量大．增加Fe的负载量，CO的脱附量减少．TPSR实验中，CO加氢反应的主要产物是甲烷．不同组分的催化剂上甲烷的生成温度有如下顺序：Rh／SiO2（482K）＜Rh－Mn－Li／SiO2（489K）＜Rh－Fe／SiO2（494K）＜Rh－Mn－Li－Fe／SiO2（501K）．甲烷峰的产生伴随着CO（s）高温脱附峰的消失，说明甲烷是由强吸附的CO加氢生成的．