Magnetic and catalytic properties of the Ni system on kieselgur

The composition, crystal structure, and character of the magnetic susceptibility of nickel—kieselgur catalyst were studied. The connectivity of the activity and selectivity of the nickel catalyst with local and collective properties of the catalyst surface was established. It was discovered that under the influence of a reaction medium, the magnetic properties of the catalyst differ substantially from its initial properties, due to the formation of clusters on the surface forming an active phase.     

Ni掺杂对Ni/MgO体系中电荷分配影响

采用密度泛函理论(DFT)计算方法,研究了载体Ni掺杂对Ni/MgO催化剂的电子结构及其对CH_4/CO_2重整反应的影响。结果显示,随着载体Ni:Mg比的增加,CH_4解离吸附和CH_x氧化过程的反应能垒均会随之升高,CH也更容易产生热解C,从而导致催化剂的活性和稳定性的下降。通过分析重整过程的Hirshfeld电荷分配,发现金属载体之间电子转移的方向会随着载体中Ni含量的上升由载体向Ni金属转移变为由Ni金属向载体转移。当Ni金属富电子时,反应物活化时电子的转移主要发生在表层Ni原子与吸附物种之间,参与氧化的CH_x物种为CH_2;当Ni金属缺电子时,反应物活化时Ni簇的电子结构基本保持稳定,电子主要在载体表层的Ni原子与反应物之间转移,CH是主要参与氧化的CH_x物种。     

Hydrogenolysis of spiro[2,3]hexane on platinized kieselguhr

Conclusions The hydrogenolysis of spiro[2,3]hexane on Pt/kieselguhr at 100° in a flow system proceeds selectively, with a cleavage of the cyclopropane C-C bond furthest away from the quaternary carbon atom, and leads to the formation of gem-dimethylcyclobutane. At 140–150° the direction of the reaction changes toward the predominant formation of ethylcyclobutane.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2806–2807, December, 1973.     

非晶态Ni基合金电极电子结构的XPS研究

用XPS测定了含P、Ce、La的Ni基合金的费米能级及各元素的芯级电子结合能,讨论了合金的电子结构以及它与析氢反应的电催化活性即析氢超电势之间的联系。结果表明：合金中各元素的原子间存在着电荷传输,它对析氢反应活性起重要作用。     

Influence of Ni nanoparticle addition and spark plasma sintering on the TiNiSn–Ni system: Structure,microstructure, and thermoelectric properties

The electronic and thermal properties of thermoelectric materials are highly dependent on their microstructure and therefore on the preparation conditions, including the initial synthesis and, if applicable, densification of the obtained powders. Introduction of secondary phases on the nano- and/or microscale is widely used to improve the thermoelectric figure of merit by reduction of the thermal conductivity. In order to understand the effect of the preparation technique on structure and properties, we have studied the thermoelectric properties of the well-known half-Heusler TiNiSn with addition of a small amount of nickel nanoparticles. The different parameters are the initial synthesis (levitation melting and microwave heating), the amount of nickel nanoparticles added and the exact pressing profile using spark plasma sintering. The resulting materials have been characterized by synchrotron X-ray diffraction and microprobe measurements and their thermoelectric properties are investigated. We found the lowest (lattice) thermal conductivity in samples with full-Heusler TiNi₂Sn and Ni₃Sn₄ as secondary phases.     

Electronic structure and magnetic properties of the graphene/Fe/Ni111 intercalation-like system

The electronic structure and magnetic properties of the graphene/Fe/Ni(111) system were investigated via combination of the density functional theory calculations and electron-spectroscopy methods. This system was prepared via intercalation of thin Fe layers (1 ML) underneath graphene on Ni(111) and its inert properties were verified by means of photoelectron spectroscopy. Intercalation of iron in the space between graphene and Ni(111) changes drastically the magnetic response from the graphene layer that is explained by the formation of the highly spin-polarized 3d(z(2)) quantum-well state in the thin iron layer.     

Electron correlation effects on magnetic properties of BH

The nuclear magnetic shielding and magnetizability tensors for the BH molecule are calculated by the coupled-Hartree–Fock method and many-body perturbation theory. As in the case of H₂, HF, and F₂, the second-order non-CHF diagrams make an inappreciable contribution.     

Electron distribution of small Ni particles and Ce ions in X and Y zeolites related to their catalytic properties

Catalytic behaviour of nickel particles smaller than 1.3 nm, encaged in X and Y zeolites, in the presence of Ce³⁺, is related to their electronic properties. In general the rates of reaction are lower than those of a standard catalyst made of 2.5 nm nickel particles on SiO₂; this is attributed to the strong localization of the Ni 3d states due to the size effect. However a high rate, more than twice the standard, is found for Ni in X zeolite, in relation with a Ni 3d ¹⁰ configuration. On the other hand the fragmentation of butane is deeper with Ni in Y support than in X support and this corresponds to a high density of Nid states at the Fermi level.     

硫在Ni_(110)表面偏析的角分辨俄歇研究

本实验采用LEED及角分辨俄歇两种手段,对硫在Ni_(110)表面的偏拆作了详细的分拆。角分辨俄歇表明:Ni_(110)表面硫的偏折存在一硫的深度分布,分布层厚度大约为2～3镍原子层厚度。而LEED观察表明,当退火温度达到900℃退火4～5秒,将得到清晰的C_(2×2)图形。     

Effects of lanthanum on the properties of bifunctional Ni/HY catalyst

A series of lanthanum modified-Ni/HY bifunctional catalysts for n-octane hydroconversion were prepared by ion-exchange method, and the influence of lanthanum contents on the activity and the selectivity was investigated. Py-FTIR and CO-DRIFTS results indicated that the addition of lanthanum could adjust the acidity and the metal state over Ni/HY catalyst, and consequently change the ratio of metal to acid functions. It was found that the best catalytic performance at the lanthanum exchange of ca. 8 wt.% was due to the suitable metal/acid ratio.     

Structure and properties of surface raney catalysts from ternary intermetallides of the Fe?Ni?Al system

Raney Ni–Fe catalysts from Fe₃NiAl₁₀ and FeNiAl₉ intermetallides have different phase compositions and structures, as found by BET, X-ray and XPS methods employed. The capacity of the catalysts in NO reduction with carbon monoxide and CH₄ oxidation by oxygen has been evaluated. Their catalytic activity is nearly the same. A higher capacity of the catalysts from FeNiAl₉ is due to their developed and stable surface which is similar to that typical for Raney Ni.

---

, , Ni–Fe- Fe₃NiAl₁₀ FeNiAl₉ . NO CH₄ . . FeNiAl₉ , Ni-.