固体表面化学发光分析 Ⅱ.单矿物和钢中镍的微量测定

本文建立了Ｎｉ（ＯＨ）＾２－ｎｎ催化剂Ｈ２Ｏ２氧化Ｌｕｍｉｎｏｌ的化学发光反应，与Ｎｉ＾２＋的催化化学发光反应比较，它更适合于固体表面化学发光分析。利用Ｎｉ＾２＋在用丙酮－盐酸－水作展开剂的纸上色谱行为中Ｒｔ值为零的特点，与大多数干扰离子进行分离，实现了单矿物和钢铁中镍的快速纸上色谱－固体表面化学发光分析。     

卟啉化合物电化学性质研究 Ⅰ.5,10,15,20-四-(4-乙酰氧基苯)卟吩及其Cu、Zn、Fe、Co、Ni配合物的合成及循环伏安研究

本文报道了５，１０，１５，２０－四（４－乙酰氧基苯）卟吩（Ｔ（４ＡＯＰ）Ｐ）及其Ｃｕ，Ｚｎ，Ｆｅ，Ｃｏ，Ｎｉ配合物的合成及其在ＣＨ２Ｃｌ２－０．１ｍｏｌ／ＩＴＢＡＰ体系中的循环伏安（ＣＶ）。研究结果。ＣＶ实验表明：Ｃｕ＾２＾＋，Ｚｎ＾２＾＝，Ｎｉ＾２＾＋离子以稳定的＋２价存在于Ｔ（４ＡＯＰ）Ｐ中，电子转移反应在卟啉环上进行，而Ｆｅ＾３＾＋，Ｃｏ＾２＾＋离子在氧化还原过程中发生价态变化。实验发现...     

Ni－B超细非晶合金的化学制备、反应机理及性质研究

本文研究了水溶液中ＮｉＣｌ２与ＫＢＨ４的反应及其产物Ｎｉ－Ｂ超细非晶合金的性质。详细探讨了反应的电化学基础和反应过程机理。发现Ｎｉ＾２＋与ＢＨ＾－４的反应独立的基本反应组成，其中不可避免地存在ＢＨ＾－４的分解即与Ｈ２Ｏ的反应，Ｎｉ－Ｂ则产生于Ｎｉ＾２＋的还原     

Ni－Cu和TiO_2－SiO_2间的相互作用及其对催化性能的影响

用表面反应改性法制备了ＴｉＯ２－ＳｉＯ２（ＴＳＯ）表面复合物载体．采用ＴＰＲ，ＩＲ，ＴＰＤＭＳ和ＴＰＳＲ－ＭＳ等技术研究了ＮＩ－Ｃｕ／ＴＳＯ间的相互作用及其对ＣＯ加氢反应的催化性能．结果表明，ＮｉＯ－ＣｕＯ与ＴＳＯ间的相互作用导致ＣｕＯ的还原温度降低和ＮｉＯ的还原温度升高，并有少量表面物种生成；还原后的Ｎｉ－Ｃｕ／ＴＳＯ催化剂表面上存在着两类活性中心，即合金相中的Ｎｉ及载体相中的Ｔｉｎ＋（或Ｔｉｎ＋－Ｏ）；ＣＯ在催化剂表面存在孪生、线式、桥式和卧式等４种吸附态；Ｈ２在催化剂表面上发生解离吸附形成Ｎｉ－Ｈ和Ｔｉｎ＋－Ｈ，前者比较活泼，是加氢反应的主要Ｈ源；卧式吸附态极易在催化剂表面裂解形成Ｎｉ－Ｃ和Ｔｉｎ＋－Ｏ，前者是加氢反应的Ｃ源，使ＣＯ加氢生成烃类的反应在Ｎｉ中心上按＂表面碳＂机理进行，其生成乙烯的选择性大于６０％．Ｈ２Ｏ的生成反应在Ｔｉｎ＋中心上按Ｔｉｎ＋－Ｏ与Ｔｉｎ＋－Ｈ或Ｎｉ－Ｈ反应的途径进行．     

Ni－Cu和MgO－SiO_2间的相互作用及其对催化性能的影响

本文用ＴＰＲ，ＩＲ，ＴＰＤ和ＴＰＳＲ等技术研究了以表面改性法制备的ＭｇＯ－ＳｉＯ２（ＭＳＯ）表面复合物担载的Ｎｉ－ＣＵ合金间的相互作用及其对ＣＯ加氢反应催化性能的影响．结果表明，ＮｉＯ－ＣｕＯ与ＭＳＯ间的相互作用导致部分ＭＯ与ＭＳＯ形成表面物种从而使金属组分氧化物还原温度明显升高；还原后的Ｎｉ－Ｃｕ／ＭＳＯ表面上存在着两类活性中心，即合金相中的Ｎｉ与载体相中的Ｍｇ２＋（或Ｍｇ２＋－Ｏ）；在两类活性中心的协同作用下，ＣＯ吸附除有孪生、线式和桥式吸附态物种外，还有一种新的卧式吸附态（Ｎｉ．．．Ｃ＝Ｏ→Ｍｇ２＋）．这种吸附态的活化程度较高，易在表面上发生裂解形成Ｎｉ－Ｃ和Ｍｇ２＋－Ｏ，其中Ｎｉ－Ｃ是加氢反应的碳源；Ｈ２在催化剂表面上发生解离吸附形成Ｎｉ－Ｈ和Ｍｇ２＋－ＯＨ，前者比较活泼，是加氢反应的氢原．ＣＯ加氢生成烃类的反应在Ｎｉ中心上按＂表面碳＂机理进行，其生成ＣＺＨ４的选择性高于８０％；Ｈ２Ｏ的生成反应按２（Ｍｇ２＋－ＯＨ）－→Ｍｇ２＋＋（Ｍｇ２＋－Ｏ）＋Ｈ２Ｏ方式进行．     

ABO3,A2BO4型复合氧化物催化剂用于CO,CH4,NH3完全氧化的比较

本文探讨了ＣＯ，ＣＨ４和ＮＨ３在ＬａＮｉＯ３，Ｌａ２ＮｉＯ４和ＬａＳｒＮｉＯ４三个催化剂上的氧化行为，并得出结论：对于ＣＯ氧化，关键步骤在于ＣＯ在催化剂表面上的络合活化。Ｎｉ＾３＋含量越高，越利于ＣＯ的络合活化。对于氨氧化，催化反应遵循氧化－还原机理。Ｎｉ＾３＋是主要的活性离子，晶格氧是主要活性氧种。对于ＣＨ４氧化，催化机理较复杂，只是发现Ａ２ＢＯ４型氧化物（Ｌａ２ＮｉＯ４，ＬａＳｒＮｉＯ４）比Ａ     

铈离子清除超氧物自由在的机理

以光辐照核黄素作为超氧物自由基（Ｏ２）源，研究了Ｃｅ＾３＋、Ｃｅ＾４＋对硝基四氮唑蓝（ＮＢＴ）还原、羟胺化的抑制作用和铈离子存在时Ｈ２Ｏ２含量、核黄素光分解、溶解氧消耗和变化以及铈离子价态的变化。从而得知，铈离子可清除Ｏ２，其机理为：Ｃｅ＾３＋供给Ｏ２电子氧化为Ｃｅ＾４＋、Ｏ２还原为Ｈ２Ｏ２；Ｃｅ＾４＋从Ｏ２获得电子还原为Ｃｅ＾３＋，Ｏ２氧化为Ｏ２。所以微量的铈离子可清除大量的Ｏ２。     

CO2加H2合成甲醇Cu—Zn—O催化剂表面化学态研究

应用ＸＲＤ、ＥＳＲ、ＵＲＤＳ、ＸＰＳ及ＸＡＥＳ等手段研究了ＣＯ２加Ｈ２合成甲醇Ｃｕ－Ｚｎ－Ｏ催化剂在还原后和反应状态下的表面化学状态。结果表明，在还原及反应状态下，催化剂表面仅能检测到ＣＵ＾０，而未发现稳定的Ｃｕ＾２＋和Ｃｕ＾＋存在；ＺｎＯ被 部分还原产生低价锌Ｚｎ＾（２－δ）＋（０＜δ＜２）。关联活性测试结果认为：Ｃｕ＾ｏ／Ｚｎ＾（２－δ）＋Ｏ构成ＣＯ２加Ｈ２合成甲醇反应的活性中心。     

PTFE—乙醚柱反相萃取层析连续分离和测定镓（Ⅲ）铟（Ⅲ）的研究

研究了在抗坏血酸存在下的６ｍｏｌ／Ｌ ＨＢｒ介质作流动相，以ＰＴＦＥ（聚四氟乙烯）负载的乙醚作固定相，反相萃取层析使微量Ｇａ（Ⅲ），Ｉｎ（Ⅲ）与Ｆｅ＾３＋、Ｔｌ＾３＋、Ｍｏ＾６＋、Ａｕ＾３＋、Ｔｉ＾４＋、Ｂｉ＾３＋、Ａｌ＾３＋、Ｍｇ＾２＋、Ｃａ＾２＋、Ｎｉ＾２＋、Ｃｏ＾２＋、Ｃｄ＾２＋、Ｚｎ＾２＋、Ｐｂ＾２＋、Ｃｕ＾２＋等多种离子分离。留于柱上的铟、镓分别用ＨＣｌ（４ｍｏｌ／Ｌ）－Ｈ２Ｏ２（３％）     

过渡元素Dawson结构的钨钒磷四元杂多配合物的合成与表征

制备了两个系列１２种尚未见文献报道的过渡金属Ｄａｗｓｏｎ结构的钨钒磷四元杂多配合物。经元素分析和热重分析确定配合物通式为Ｋ９，１０［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１５Ｖ２Ｏ６１］．ｘＨ２Ｏ和Ｋ１０，，１１［Ｐ２Ｍ（Ｈ２Ｏ）Ｗ１４Ｖ３Ｏ６１］．ｘＨ２Ｏ）（Ｍ＝Ｆｅ＾３＾＋，Ｃｏ＾３＾＋，Ｎｉ＾２＾＋，Ｍｎ＾２＾＋，Ｃｕ＾２＾＋，Ｚｎ＾２＾＋＿），采用ＩＲ，ＵＶ，ＮＭＲ，ＥＳＲ和ＸＲＤ等方法进行了结构表征。     

Adsorption of carbon dioxide by X zeolites exchanged with Ni2+ and Cr3+: isotherms and isosteric heat

The adsorption of CO2, at intervals of 30 K from 303 K was carried out on M(n+)X zeolites (M(n+)=Ni2+ or Cr3+) exchanged at different degrees. The structural regularity of the zeolite lattice of NaX and the existence of well-defined cavities within which the adsorbate molecules are lodged suggest that it should be possible to use various isotherm equations. Several models were thus used to describe the experimental isotherms. The best fit of adsorption isotherm data is obtained with the Sips model. The Volmer model also describes satisfactorily the isotherms of CO2 adsorption by NaX, Ni(x)X, and Cr(x)X. Analysis of the isosteric heat reveals a character energetically heterogeneous for NaX and Ni(x)X samples exchanged at a higher degree of Ni2+ exchange and at low coverage. Specific interaction is also obtained between the adsorbate molecules and Cr(x)X exchanged at a lower degree. From these considerations, hypotheses will be advanced to describe the behavior of the adsorbed phase within zeolitic cavities.     

以水滑石及类水滑石为前体制备的Ni、Mg、Al混合氧化物的合成和表征

采用了BET、XRD、TG-DSC、TPR、FTIR、微量量热吸附和异丙醇催化反应等测试方法，对以共沉淀法合成的水滑石(HT)和类水滑石(HTLcs)为前体制备的4Mg/Al、3Ni/Mg/Al、3.5Ni/0.5Mg/Al和4Ni/Al混合氧化物和前体进行了研究。测定表明：制备的混合氧化物的比表面积较大、随着镍含量的增大而降低。由于Ni²⁺离子的氧化还原属性，Ni²⁺离子进入后，削弱了HT层对阴离子的键合能力，从而使得样品的热分解温度及热稳定性降低，导致焙烧后     

Homogeneous precipitation of layered Ni(II)-Cr(III) double hydroxides

An adequate account of the hydrolytic properties of Cr3+ and Ni2+ allows setting the conditions for homogeneous nucleation of layered Ni(II)-Cr(III) double hydroxides; water exchange and hydrolysis rate constants indicate that, at very high rates of base dosing, formation of heteronuclear Cr(III)-Ni(II) hydroxo species should prevail over precipitation of active Cr(OH)3. This is realized by the urea method under microwave-assisted hydrothermal conditions. This approach yields crystalline Ni1-xCrx(OH)2(CO3)x/2nH2O (x approximately 0.32-0.36) in less than 5 min at 453 K; higher degrees of crystallinity are obtained at higher temperatures and/or longer aging times. Formation of Ni(II)-Cr(III) LDHs upon microwave-assisted hydrothermal aging of freshly coprecipitated Ni(OH)2+Cr(OH)3 mixtures takes longer, due to a different operating mechanism. The implications of the advanced rationale for the design of synthesis procedures are stressed. It is proposed that homogeneous nucleation of Ni(II)-Cr(III) LDHs involves the edge-on condensation of planar heteronuclear Cr(III)-Ni(II) hydroxo trimers. Ordered aggregation of primary particles leads to the final platelet crystals, a process that involves the exchange of CO2-(3) ions dangling at the crystallites' edges by bridging OH-.     

Solubility and solubility product of crystalline Ni(OH)2

The solubility of crystalline Ni(OH)₂ was studied in solutions of 0.01M NaC10₄ with pH ranging from 7 to near 14. Equilibrium was approached both from over-and undersaturation, and the equilibration times extended from 3 to 90 days. The solubility of Ni(OH)₂(c) in the pH range of approximately 7 to 11.3 was effectively modeled by including aqueous Ni²⁺ and NiOH⁺ species. Values of the logarithm of the thermodynamic equilibrium constants for the reactions [Ni(OH)₂(c) ⇌ Ni²⁺ + 2OH^-] and [Ni²⁺ + OH^- ⇌ Ni(OH)⁺] were determined to be -16.1±0.1 and 5.65 ± 0.10, respectively. These data, in conjunction with Pitzer ion interaction parameters given in the literature, were used to model the reported solubilities of Ni(OH)₂(c) in chloride, sodium acetate, and potassium chloride solutions. The model predictions for these systems were in excellent agreement with the experimental data from the literature.     

ZnO/γ-Al2O3体系的状态和表面结构的研究(Ⅰ)

本文用X射线衍射和X射线光电子能谱法研究了用浸渍法制取的ZnO/γ-Al_2O_3样品。实验表明, ZnO 极易与γ-Al_2O_3发生固相反应, 经240 ℃烘烤就可以观察到反应的进行。样品的结构和形态依其组成和焙烧条件而异。氧化锌含量较低的样品由缺锌铝酸锌构成, 基表相Zn浓度取决于样品组成和焙烧温度。氧化锌含量较高的样品分两种情况: 低温焙烧的样品由Zn_xAl_2O_(3+x)(x<1)和晶相ZnO构成; 高温焙烧的样品可生成化学计量比的ZnAl_2O_4, 其上还单层分散着一层ZnO。仅当ZnO/ZnAl_2O_4中ZnO的含量超过此分散量时, 才有晶相ZnO析出。     

Boosting Hydrogen Oxidation Activity of Ni in Alkaline Media through Oxygen‐Vacancy‐Rich CeO2/Ni Heterostructures

The search for highly efficient platinum group metal (PGM)‐free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline electrolytes remains a great challenge in the development of alkaline exchange membrane fuel cells (AEMFCs). Here we report the synthesis of an oxygen‐vacancy‐rich CeO₂/Ni heterostructure and its remarkable HOR performance in alkaline media. Experimental results and density functional theory (DFT) calculations indicate the electron transfer between CeO₂ and Ni could lead to thermoneutral adsorption free energies of H* (ΔG_H*). This, together with the promoted OH* adsorption strength derived from the abundance of oxygen vacancies in the CeO₂ species, contributes to the excellent HOR performance with the exchange current density and mass activity of 0.038 mA cm_Ni^?2 and 12.28 mA mg_Ni^?1, respectively. This presents a new benchmark for PGM‐free alkaline HOR and opens a new avenue toward the rational design of high‐performance PGM‐free electrocatalysts for alkaline HOR.     

Hydration/expansion and cation charge compensation modulate the Brønsted basicity of distorted clay water

This letter addresses how iron redox cycling and the hydration properties of the exchangeable cation influence the Br?nsted basicity of adsorbed water in 2:1 phyllosilicates. The probe pentachloroethane undergoes facile dehydrochlorination to tetrachloroethene, attributed to increases in the Br?nsted basicity of near-surface hydrating water molecules following the reduction of structural Fe(III) to Fe(II). This dehydrochlorination process is studied in the presence of Na(+)- or K(+)-saturated Upton montmorillonite [(Na0.82 (Si7.84 Al0.16)(Al3.10 Fe(3+)0.3 Mg0.66) O20 (OH)4] or ferruginous smectite [(Na0.87 Si7.38 Al0.62)(Al1.08) Fe(3+)2.67 Fe(2+)0.01 Mg0.23) O20 (OH)4]. The effect of iron redox cycling on pentachloroethane dehydrochlorination is studied using reduced or reduced and reoxidized smectite samples saturated with Na+ (fully expanded clay) or K+ (fully collapsed clay). Variations in the clay Br?nsted basicity following Na+ -for- K+ exchange are explained by cationic charge compensation or interlayer hydration/expansion imposed by the nature of the exchangeable cation. Inverse relations between K+ fixation and clay water content as well as trends in pentachloroethane transformation indicate that increases in the Br?nsted basicity result from increases in the clay hydrophilicity and shifts in the local activity of distorted clay water. Potassium fixation causes partially collapsed smectites bearing low amounts of structural Fe(II) to have a similar reactivity to that of fully expanded smectites (Na+ form) bearing higher amounts of structural Fe(II). In particular, the conversion of up to 80% of the pentachloroethane to tetrachloroethane by K+ -saturated, reoxidized Upton was explained because the fixation of K+ causes nonreversible expansion and incomplete reoxidation of structural Fe(II), which contributes to the stabilization of charge density near sites bearing Fe(II). Higher pentachloroethane conversions by Upton montmorillonite over ferruginous smectite, however, suggest that charge dispersion rather than site specificity contributes predominantly to clay reactivity. Thus, clay interlayer hydration/expansion imposed by the nature of the exchangeable cation alters water dissociation and proton exchange in Fe(II)-Fe(III) phyllosilicates susceptible to iron redox cycling.     

Intercalation of vanadate in Ni, Zn layered hydroxyacetates

Interlayer acetate anions in layered double hydroxyacetates of Ni²⁺ and Zn²⁺ have been exchanged by oxovanadates following three synthetic routes (at 60°C, under hydrothermal conditions and after preswelling with caprylate anions) and different pH; direct exchange at room temperature was not successful. Complete exchange was achieved under adequated conditions, and the precise nature of the interlayer anion depends on the pH during exchange: at low pH (4.5), the presence of α-VO₃ chains, with anchoring (grafting) of the species to the hydroxide layers, is proposed. At higher pH (9.5) V₂O₇⁴⁻ species are present in the interlayer. Thermal decomposition of these vanadate-intercalated products leads to formation of orthorhombic Ni²⁺ and Zn²⁺ vanadates, together with NiO.     

In Situ and Theoretical Studies for the Dissociation of Water on an Active Ni/CeO2 Catalyst: Importance of Strong Metal–Support Interactions for the Cleavage of O–H Bonds

Water dissociation is crucial in many catalytic reactions on oxide‐supported transition‐metal catalysts. Supported by experimental and density‐functional theory results, the effect of the support on O? H bond cleavage activity is elucidated for nickel/ceria systems. Ambient‐pressure O 1s photoemission spectra at low Ni loadings on CeO₂(111) reveal a substantially larger amount of OH groups as compared to the bare support. Computed activation energy barriers for water dissociation show an enhanced reactivity of Ni adatoms on CeO₂(111) compared with pyramidal Ni₄ particles with one Ni atom not in contact with the support, and extended Ni(111) surfaces. At the origin of this support effect is the ability of ceria to stabilize oxidized Ni²⁺ species by accommodating electrons in localized f‐states. The fast dissociation of water on Ni/CeO₂ has a dramatic effect on the activity and stability of this system as a catalyst for the water‐gas shift and ethanol steam reforming reactions.     

Synthesis of NiGa layered double hydroxides. A combined EXAFS, SAXS, and TEM study. 2. Hydrolysis of a Ni2+/Ga3+ solution

Takovites are nickel-based layered double hydroxides (LDH) with a general formula that can be written as Ni(1-x)Al(x)(OH)2, A(z-)(x/z), yH(2)O, where A is a compensating interlayer anion. As in some other LDH samples, the positive charge of the layer can be adjusted upon synthesis and various anions can be exchanged in the interlayer region. It is then important to understand the synthesis pathway of these materials. We then undertook a study on the hydrolytic behavior of pure Ni salts and mixtures of Ni and Ga salts. This paper focuses on the hydrolysis of Ni(2+) and Ga(3+) ions, together in solution, carried out by base addition. The samples will be defined by their hydrolysis ratio R = [OH(-)]/([Ni(2+)] + [Ga(3+)]). Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) were used to obtain information on the colloidal species size and shape on a large scale. Each hydrolyzed sample was also studied by Ni K-edge and Ga K-edge extended X-ray absorption fine structure (EXAFS) to obtain information on the local structure of the species in suspension. SAXS curves reveal the presence of bidimensional objects whatever the R values. The platelets formed for R values >/=1.1 are slightly thicker and smaller in size, which may be linked to their different natures. Complementary information is provided by TEM analysis: the first colloids formed have a structure very close to that of alpha-GaOOH, as shown by electronic diffraction. Those structures are progressively replaced by Ni-Ga LDH platelets with increasing hydrolysis ratio, which are the only species in suspension for R = 2.0, as shown by XRD. EXAFS results confirm the complete hydrolysis of gallium before the formation of Ni-Ga LDH phases.