MnO_x-CeO_2上表面氧性质及其催化碳烟燃烧性能

运用TPO,XRD,BET,O2-TPD,H2-TPR,XPS等技术,研究了在CeO2中引入不同Mn含量对催化剂表面氧性质的影响,并重点探讨了吸附于氧空位上的原子吸附氧O-与催化碳烟燃烧活性的关联。结果表明:将Mn中引入CeO2后,MnOx-CeO2晶格中可形成较CeO2更多的氧空位,并有利于氧的活化和迁移,生成了较多原子吸附氧O-;MnOx(0.4)-CeO2在碳烟起燃温度区间有最多的原子吸附氧O-,其碳烟起燃活性最高,对应的起燃温度是346℃,比无催化剂时降低了111℃,比CeO2降低了35℃。     

氮化钛、碳化钛、低价钛合量、二氧化钛物相分析的研究

本工作研究了钛精矿氮化、碳化产品中钛化物的物相分析。试料中钛化物主要为氮化钛(TiN)、碳化钛(TiC)、碳氮化钛、钛的各种氧化物(TiO_2、Ti_3O_5、Ti_2O_3、TiO)、钛铁矿等。氮化钛、碳化钛的物相分析一般为两种方法:一是通过测定其中氮或碳,确定氮化钛、碳化钛的含量。二是使各种钛化物彼此分离,分别测定钛,确定其各组分含量。金属试料中钛化物的物相分析多用此法。我们采用选择性溶解法。有关氮化钛、碳化钛、各种氧化物,在一些溶剂及它们混合物中的稳定性已有介绍。但由于钛化物的状态及实验条件不同,结论并非一致。因此,本实验室制备了几种钛化物以及光谱纯二氧化钛、金红石、碳化钛、金属钛试剂进行了试验,建立了氮化钛、碳化钛、低价钛(TiO、Ti_2O_3、黑钛石)合量以及二氧化钛的测定方法。     

基于黄药子药渣制备微孔碳材料及其吸附氯霉素的研究

本文通过NaCl/KCl活化黄药子残渣制备微孔碳材料(DBL-800-AC)用于氯霉素的吸附研究。采用粉末X射线衍射仪(PXRD)、拉曼光谱仪(Raman)、比表面积及孔径分析仪(BET)等仪器表征碳材料稳定性、化学组成、石墨化程度和孔隙结构。探讨NaCl/KCl活化物、溶液pH、温度、氯霉素初始浓度和离子强度对氯霉素吸附性能的影响。采用NaCl/KCl活化剂进行活化后,DBL-800-AC的比表面积达到1634 m²/g,总的孔体积为0.85 m²/g,表明DBL-800-AC微孔碳具有丰富的孔隙结构。当pH值为5时,温度35℃时,DBL-800-AC吸附氯霉素的吸附量约900 mg/g。吸附过程中动力学模型符合二级动力学模型,等温模型可用Freundlich吸附等温模型描述。中药药渣制备的微孔碳材料是有效的去除水中氯霉素的吸附剂。     

生物碳质吸附剂对水中有机污染物的吸附作用及机理

以松针为生物质代表,通过控制不同炭化温度（100～700℃）,制备了一系列生物碳质吸附剂,表征了其结构和表面特征;以4-硝基甲苯为目标,探讨吸附剂在水中对有机污染物的吸附性能、机理及与其结构特征之间的定量关系,为制备经济高效吸附剂和预测其吸附性能与机制提供理论依据．结果表明,生物碳质吸附剂的芳香性随炭化温度的升高而急剧增加、极性指数（（N＋O）/C）则急剧降低,逐渐从“软碳质”过渡到“硬碳质”,同时其比表面积则迅速增大．生物碳质吸附剂对水中4-硝基甲苯具有强的吸附能力,等温吸附曲线符合Freundlich方程,N指数和1gKf与其芳香性呈良好的线性关系．定量描述了分配作用与表面吸附对生物碳质总的吸附作用的贡献．表面吸附的贡献量随炭化温度升高而迅速增大,表面饱和吸附量与吸附剂的比表面积呈良好的线性正关系;硬碳质吸附剂的最大表面吸附量（Qmax,SA）与理论计算值（2．45μmol／m^2）相当,而软碳质吸附剂的Qmax．SA值则高于理论值．生物碳质的分配作用（Kom）取决于分配介质与有机污染物的“匹配性”和“有效性”,Kom值随（N＋O）/C降低呈现先升高后降低的趋势．     

离子交换树脂基多孔碳材料的制备及其CO_2吸附性能研究

以废弃的阳离子交换树脂为原料,采用Zn Cl2活化法,在原料与活化剂质量比为1:2情况下,研究了不同的活化温度(300℃、400℃、500℃、600℃)对多孔碳材料孔隙结构和CO2吸附性能的影响。通过N2吸附脱附、扫描电子显微镜(SEM)、透射电镜(TEM)等对样品的孔隙结构和形貌进行了表征。采用变压吸附法,在常温常压下测试了样品对CO2的吸附性能,结果表明,随着活化温度的升高,多孔碳材料的比表面积、孔容、平均孔径等随之减小,当活化温度为400℃时,其微孔孔容比达到最大值49.6%,比表面积达到最大值1136 m2/g;当活化温度为600℃时,CO2吸附量达到了最大值9.2wt%(常温常压下),表明了CO2吸附量与比表面积大小无直接关系,受超微孔孔径分布的影响更大。     

碱活化多孔碳用于分离甲苯及活化/吸附机理

采用生物质木质素磺酸钠(SLS)为碳源, 先与硬模板NaCl混合预碳化, 再加入活化剂NaOH在氮气保护下升温至850 ℃碳化, 得到SLS基碱活化的多孔碳吸附剂(SPCN). 将SPCN用于吸附液体石蜡中芳香烃甲苯, 对比研究了不同活化剂加入量对SPCN结构、 性质及吸附效果的影响. 结果表明, SPCN表面具有丰富的官能团和发达的微/介孔结构, 活化剂加入量对比表面积的影响为先增大后减小, 碱/碳质量比为1∶1时比表面积达到最大值(710.4 m ²/g); 吸附量与比表面积呈正相关, 样品SPCN-1的最大吸附量为2875.17 mg/g, 远高于商业吸附剂, 经5次吸附-解吸循环后仍保持92.5%的吸附效率. 探究了活化机理, NaOH、 碳质和气体发生氧化还原反应释放气体留下孔隙, 经充分酸洗、 水洗后得到永久孔道. 最后, 结合扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 拉曼光谱(Raman)、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)和比表面积分析等结果证明了吸附机理主要是孔隙填充效应、 范德华力、 π-π相互作用及电子供/受体作用的共同作用. 首次报道了SPCN应用的新方向并探究了活化与吸附机理, 制备方法简易、 经济, 产品循环稳定性好、 无污染, 有望用于工业化生产.     

球状纳米介孔碳和HZSM-5分子筛在二苯并噻吩吸附脱硫中的应用

采用软模板法制备了粒径范围为50 nm～100 nm的球状纳米介孔碳(MCN),与HZSM-5分子筛机械混合获得介/微孔混合吸附剂,用于二苯并噻吩的吸附脱硫研究。XRD、BET、SEM和TEM等分析结果表明,MCN比表面积为214 m²/g,孔径为5.1 nm,混合吸附剂的比表面积、孔容、孔径均处于MCN和HZSM-5分子筛两者之间,且两者混合均匀。吸附脱硫实验表明,HZSM-5分子筛对二苯并噻吩的吸附脱硫率最差(脱硫率4.8%),而MCN的脱硫性能最优(脱硫率70%),混合吸附剂中随MCN含量增加二苯并噻吩的吸附脱硫性能逐渐提高,且MCN表现出了较好的可重复性能,经过4次循环后吸附容量保留率为79%。Freundlich等温模型比Langmuir等温模型更适合描述二苯并噻吩在上述吸附剂表面的吸附过程,吸附动力学实验数据说明二苯并噻吩在该系列吸附剂上的吸附更符合二级动力学模型。     

玻碳电极上Ru（bpy）3^2＋的吸附及其电致化学发光的研究

通过电化学循环伏安法和电致化学发光方法,研究了Ru(bpy)32 在玻碳电极上的吸附,研究结果表明,2Ru(bpy)3 的浓度和与玻碳材料接触的时间,直接影响了Ru(bpy)32 在玻碳上的吸附.还考察了吸附的Ru(bpy)32 在玻碳电极上被氧化后脱附的情况.     

功能化有序介孔碳对重金属离子Cu(Ⅱ)、Cr(Ⅵ)的选择性吸附行为

以三嵌段共聚物F127为模板剂,酚醛树脂为碳源,正硅酸乙酯为硅源,三组分共组装合成介孔碳-氧化硅纳米复合物,再经HF去除氧化硅,得到有序介孔碳(OMC).X射线衍射(XRD)、透射电子显微镜(TEM)、低温N2吸脱附(BET)等测试表明,所得样品具有高度有序的介孔结构,比表面积和孔容分别为1330m2·g-1和2.13cm3·g-1,平均孔径6.4nm.对其先氧化、后氯化、再胺化,得到不同胺基接枝量的胺化介孔碳(C-NH2(m),m为加入的乙二胺的质量(g)).傅里叶变换红外(FT-IR)光谱表征结果证实,胺基官能团成功接枝到有序介孔碳表面.TEM测试表明介孔碳的有序孔道结构得到了较好的保持.以有序介孔碳、胺化介孔碳作吸附剂对Cu(Ⅱ)、Cr(Ⅵ)进行选择性吸附研究.结果表明:功能化修饰前,样品对Cu(Ⅱ)、Cr(Ⅵ)饱和吸附量分别为213.33、241.55mg·g-1;修饰后饱和吸附量可分别达到495.05、68.21mg·g-1.功能化介孔碳表现了较强的选择性吸附Cu(Ⅱ)的能力.     

玻碳电极上Ru(bpy)23+的吸附及其电致化学发光的研究

通过电化学循环伏安法和电致化学发光方法,研究了Ru(bpy)23+在玻碳电极上的吸附,研究结果表明,Ru(bpy)23+的浓度和与玻碳材料接触的时间,直接影响了Ru(bpy)23+在玻碳上的吸附.还考察了吸附的Ru(bpy)23+在玻碳电极上被氧化后脱附的情况.     

Surface-Modified Metallic Biomaterials in Contact with Blood and Endothelial Cells

Summary : The experimental procedures were undertaken in order to characterize of surface-modified metallic substrates. Results revealed that carbon layers coating the substrates made metallic surface generally more biocompatible and more resistant to biofilm formation. Titanium-nitride or titanium carbo-nitride layers on the titanium alloy (Ti6Al4V) allow for modulation of thrombogenity degree of the surface. Our investigations employed several methods: fluorescence and electron microscopy techniques, SPR-biosensor technology, 2D-electrophoresis and flow cytofluorymetry.     

Small cluster models of the surface electronic structure and bonding properties of titanium carbide, vanadium carbide, and titanium nitride

Density functional theory (DFT) calculations on stoichiometric, high-symmetry clusters have been performed to model the (100) and (111) surface electronic structure and bonding properties of titanium carbide (TiC), vanadium carbide (VC), and titanium nitride (TiN). The interactions of ideal surface sites on these clusters with three adsorbates, carbon monoxide, ammonia, and the oxygen atom, have been pursued theoretically to compare with experimental studies. New experimental results using valence band photoemission of the interaction of O(2) with TiC and VC are presented, and comparisons to previously published experimental studies of CO and NH(3) chemistry are provided. In general, we find that the electronic structure of the bare clusters is entirely consistent with published valence band photoemission work and with straightforward molecular orbital theory. Specifically, V(9)C(9) and Ti(9)N(9) clusters used to model the nonpolar (100) surface possess nine electrons in virtually pure metal 3d orbitals, while Ti(9)C(9) has no occupation of similar orbitals. The covalent mixing of the valence bonding levels for both VC and TiC is very high, containing virtually 50% carbon and 50% metal character. As expected, the predicted mixing for the Ti(9)N(9) cluster is somewhat less. The Ti(8)C(8) and Ti(13)C(13) clusters used to model the TiC(111) surface accurately predict the presence of Ti 3d-based surface states in the region of the highest occupied levels. The bonding of the adsorbate species depends critically on the unique electronic structure features present in the three different materials. CO bonds more strongly with the V(9)C(9) and Ti(9)N(9) clusters than with Ti(9)C(9) as the added metal electron density enables an important pi-back-bonding interaction, as has been observed experimentally. NH(3) bonding with Ti(9)N(9) is predicted to be somewhat enhanced relative to VC and TiC due to greater Coulombic interactions on the nitride. Finally, the interaction with oxygen is predicted to be stronger with the carbon atom of Ti(9)C(9) and with the metal atom for both V(9)C(9) and Ti(9)N(9). In sum, these results are consistent with labeling TiC(100) as effectively having a d(0) electron configuration, while VC- and TiN(100) can be considered to be d(1) species to explain surface chemical properties.     

Nucleophilic attack toward group 4 metal complexes bearing reactive 1-Aza-1,3-butadienyl and imido moieties

Unique (1-aza-2-butenyl)titanium complexes bearing a phosphonium ylide moiety [Ti=NTbt{C(Me)(PR3)CH=C(Me)N(Mes)}Cl] (3-5, Tbt = 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl, Mes = 2,4,6-trimethylphenyl) were formed by the nucleophilic attack of PMe3, P(n-Bu)3, and 1,2-bis(dimethylphosphino)ethane (dmpe) toward the corresponding (1-aza-1,3-butadienyl)titanium complex, [Ti=NTbt{C(Me)CHC(Me)N(Mes)}(mu-Cl)2Li(tmeda)] (2a). The reaction of a lithium beta-diketiminate, [Li{N(Tbt)C(Me)CHC(Me)N(Mes)}] (1) with [TiIICl2(dmpe)2] also resulted in the formation of the same complex 5. Density functional theory calculation indicated that the negative charge of the model molecule of 3 was slightly delocalized to the C3N plane. In addition, the calculation of the model molecule of 2a suggested the electrophilicity of 2a at the carbon atom connecting to the titanium atom. Interestingly, the reaction of zirconium and hafnium analogues (2b and 2c) with PMe3 and dmpe did not proceed. In contrast to the cases of phosphine reagents, pyridine which was found to undergo the nucleophilic attack toward the titanium center of 2a gave the pyridine-coordinated titanium-imide [Ti=NTbt{C(Me)CHC(Me)N(Mes)}Cl(py)] (7).     

Heterobimetallic reductive cross-coupling of benzonitrile with carbon dioxide, pyridine, and benzophenone

Described herein are heterobimetallic radical cross-coupling reactions between the benzonitrile adduct of the molybdenum(III) complex Mo(N[t-Bu]Ar)3 (Ar = 3,5-C6H3Me2) and titanium(III) complexes with carbon dioxide, pyridine, and benzophenone. The titanium(III) system employed was either Ti(N[t-Bu]Ar)3 (Ar = 3,5-C6H3Me2) or Ti(N[t-Bu]Ph)3. Crystal structure studies are described for the Mo/PhCN/CO2/Ti coupled system and for an analogue of the Mo/PhCN/Ph2CO/Ti coupled system in which PhCN is replaced with 2,6-Me2C6H3CN. In the case of the couplings involving pyridine and benzophenone, C-C bond formation takes place with dearomatization, with the new C-C bond being formed between the nitrile carbon of PhCN and the para carbon of pyridine or one of the benzophenone phenyl groups. Of the radical metal complex/substrate adducts invoked in this work, that between titanium(III) and CO2 is the only one not directly observable. In all cases, the selective cross-coupling reactions are interpreted as arising by heterodimerization of titanium(III) substrate complexes (substrate = CO2, py, or Ph2CO) with the persistent molybdenum-PhCN radical adduct. All of the heterobimetallic coupling products are diamagnetic, and the metal ions Ti and Mo in them both are assigned to the formal 4+ oxidation state.     

Dissolution kinetics of titanium dioxide nanoparticles: the observation of an unusual kinetic size effect

Different types of industrially produced titanium dioxide nanoparticles and a precipitated titanium dioxide have been dissolved in aqueous NaCl solutions at temperatures of 25 and 37 degrees C. The titanium concentration in solution with regard to dependence on time has been determined up to 3000 h after starting the dissolution experiment. The effect of particle size, pH value, temperature, background electrolyte concentration, and mass concentration of titanium dioxide exposed to the liquid phase has been studied. The nanoparticles have been characterized by N2 physisorption measurements and XRD. The total dissolved titanium in solution has been determined by adsorptive stripping voltammetry (AdSV) and inductively coupled plasma mass spectrometry (ICP-MS). A new kinetic size effect has been observed. It turns out that this effect can be explained by applying an already existing phenomenological thermodynamic and kinetic model. The model describes all possible phenomena in a colloidal dispersion, nucleation, growth of particles, Ostwald ripening, and dissolution of particles using a uniform concept.     

Metallorganic routes to nanoscale iron and titanium oxide particles encapsulated in mesoporous alumina: formation, physical properties, and chemical reactivity

Iron and titanium oxide nanoparticles have been synthesized in parallel mesopores of alumina by a novel organometallic "chimie douce" approach that uses bis(toluene)iron(0) (1) and bis(toluene)titanium(0) (2) as precursors. These complexes are molecular sources of iron and titanium in a zerovalent atomic state. In the case of 1, core shell iron/iron oxide particles with a strong magnetic coupling between both components, as revealed by magnetic measurements, are formed. M?ssbauer data reveal superparamagnetic particle behavior with a distinct particle size distribution that confirms the magnetic measurements. The dependence of the M?ssbauer spectra on temperature and particle size is explained by the influence of superparamagnetic relaxation effects. The coexistence of a paramagnetic doublet and a magnetically split component in the spectra is further explained by a distribution in particle size. From M?ssbauer parameters the oxide phase can be identified as low-crystallinity ferrihydrite oxide. In agreement with quantum size effects observed in UV-visible studies, TEM measurements determine the size of the particles in the range 5-8 nm. The particles are mainly arranged alongside the pore walls of the alumina template. TiO2 nanoparticles are formed by depositing 2 in mesoporous alumina template. This produces metallic Ti, which is subsequently oxidized to TiO2 (anatase) within the alumina pores. UV-visible studies show a strong quantum confinement effect for these particles. From UV-visible investigations the particle size is determined to be around 2 nm. XPS analysis of the iron- and titania- embedded nanoparticles reveal the presence of Fe2O3 and TiO2 according to experimental binding energies and the experimental line shapes. Ti4+ and Fe3+ are the only oxidation states of the particles which can be determined by this technique. Hydrogen reduction of the iron/iron-oxide nanoparticles at 500 degrees C under flowing H2/N2 produces a catalyst, which is active towards formation of carbon nanotubes by a CVD process. Depending on the reaction conditions, the formation of smaller carbon nanotubes inside the interior of larger carbon nanotubes within the alumina pores can be achieved. This behavior can be understood by means of selectively turning on and off the iron catalyst by adjusting the flow rate of the gaseous carbon precursor in the CVD process.     

Comparative Electrochemical Study of N‐, C‐terminal and Integral Centrin on Adsorption and Metal‐Binding Properties

The adsorption behavior of apo‐ciliate Euplotes octocarinatus centrin (EoCen) and N(C)‐terminal domain of EoCen (N(C)‐EoCen) at a glassy carbon (GC) electrode is studied by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Interestingly, the adsorption isotherms of C‐EoCen, N‐EoCen and EoCen at a GC surface differ from one another. It is considered to be associated with the different aggregation properties of three proteins. Furthermore, we analyze the metal‐binding properties of centrin and the followed changes in protein structure upon metal‐binding. Corresponding to the four binding sites of EoCen, it shows four no‐equiv signals of CV or EIS change. It indicates that the four different binding sites of EoCen can be discriminated by the EIS titration curves, which is in contrast with conventional use of spectral method. According to the electrostatic potential at the molecular surface of proteins, the favored orientation of N‐EoCen and C‐EoCen on the GC surface is modeled. These models can well explain the results of titration curves of Eu³⁺ to N(C)‐EoCen. This work has established the electrochemical methodology which can be used to measure metal‐binding sites involved and reveal the contribution of each metal site to the whole protein conformational change.     

2-Hydroxy-1-naphthaldoxime as an analytical reagent for titanium(IV)

2-Hydroxy-1-naphthaldoxime is proposed as a new selective and sensitive reagent for titanium. The oxime complex can be dried to constant weight at 105-110 degrees and the conversion factor is 0.1793. The method is sensitive and gives reproducible results. Quantitative separation of titanium(IV) from iron(III) and other metals by this method gives good results. The method has been applied to the gravimetric determination of titanium(IV) in ilmenite and the results are in good agreement with those obtained by the cupferron method. The dried complex has definite composition [TiO(OH)(C(11)H(8)O(2)N)](2) and is a non-electrolyte. The dimeric structure proposed for the complex is based on evidence from elemental analysis, molecular weight determination, magnetic susceptibility and infrared spectral data.     

Sodium niobate adsorbents doped with tantalum (TaV) for the removal of bivalent radioactive ions in waste waters

Mesoporous silica containing a large amount of isolated Ti was prepared from an alkoxytitanosiloxane precursor through a hard template method. Isopropoxytris(tris-tert-butoxysiloxy)titanium (((i)PrO)Ti[OSi(O(t)Bu)(3)](3), TS3) was synthesized and TS3 was mixed with mesoporous carbon (CMK-3), a hard template. The mixture was pyrolyzed at 180 °C to form a composite consisting of titanosilica and the hard template. After calcination at 600 °C for the removal of the carbon template, the titanium species were not transformed to anatase TiO(2), proved by DR-UV-Vis, FTIR, XPS, and XRD, while the ESR results indicated the presence of isolated Ti. The mesoporous structure was verified by SEM, TEM, and N(2) adsorption. The Si/Ti ratio of the product was consistent with that of the precursor. All the results show that the material prepared from the precursor is ordered mesoporous silica containing a large amount of isolated Ti in the frameworks. The use of well-defined alkoxytitanosiloxane precursor leads to the formation of mesoporous silica with exactly controlled composition of titanium with neither loss of Ti nor transformation to anatase.     

Azaphilic versus Carbophilic Coupling at CN Bonds: Key Steps in Titanium‐Assisted Multicomponent Reactions

Consecutive C‐ and N‐arylation of N‐heterocyclic nitriles is mediated by titanium(IV) alkoxides. The carbo‐ and azaphilic arylation step may be separated by choosing the order in which the two equivalents of aryl transfer reagent are added. In the course of this transformation, the ancillary N‐heterocycle acts as both a directing anchor group and electron reservoir. In the selectivity‐determining step, the selectivity is governed by a choice between (direct) C‐ and Ti‐arylation; the latter opens up a reaction pathway that allows further migration to the nitrogen atom. The isolation of metal‐containing aggregates from the reaction mixture and computational studies gave insights into the reaction mechanism. Subsequently, a multicomponent one‐pot protocol was devised to rapidly access complex quaternary carbon centers.