Synthesis of CoOOH nanorods and application as coating materials of nickel hydroxide for high temperature Ni-MH cells

Studies on nanoscale materials have received great interest in both fundamental and applied aspects in recent years. In this letter, we report the synthesis of CoOOH nanorods and their possible applications as coating materials on nickel hydroxide for high-temperature nickel-metal hydride (Ni-MH) cells. The morphology and structure of CoOOH nanorods and coated nickel hydroxide particles are investigated by transmission electron microscopy, X-ray diffraction, and scanning electron microscopy, respectively. The electrochemical properties in the cylindrical AA size Ni-MH cells are evaluated. Our results show that the Ni-MH cells, where the positive electrodes are composed of such nanometer sized CoOOH coatings, have a higher capacity available and good performance at elevated temperatures of >50 degrees C.     

Bonding and stability of the hydrogen storage material Mg(2)NiH(4)

Structural stability and bonding properties of the hydrogen storage material Mg(2)NiH(4) (monoclinic, C2/c, Z = 8) were investigated and compared to those of Ba(2)PdH(4) (orthorhombic, Pnma, Z = 8) using ab initio density functional calculations. Both compounds belong to the family of complex transition metal hydrides. Their crystal structures contain discrete tetrahedral 18 electron complexes T(0)H(4)(4-) (T = Ni, Pd). However, the bonding situation in the two systems was found to be quite different. For Ba(2)PdH(4), the electronic density of states mirrors perfectly the molecular states of the complex PdH(4)(4-), whereas for Mg(2)NiH(4) a clear relation between molecular states of TH(4)(4-) and the density of states of the solid-state compound is missing. Differences in bonding of Ba(2)PdH(4) and Mg(2)NiH(4) originate in the different strength of the T-H interactions (Pd[bond]H interactions are considerably stronger than Ni[bond]H ones) and in the different strength of the interaction between the alkaline-earth metal component and H (Ba[bond]H interactions are substantially weaker than Mg[bond]H ones). To lower the hydrogen desorption temperature of Mg(2)NiH(4), it is suggested to destabilize this compound by introducing defects in the counterion matrix surrounding the tetrahedral Ni(0)H(4)(4-) complexes. This might be achieved by substituting Mg for Al.     

Methane to Liquid Hydrocarbons over Tungsten-ZSM-5 and Tungsten Loaded Cu/ZSM-5 Catalysts

Metal containing ZSM-5 can produce higher hydrocarbons in methane oxidation. Many researchers have studied the applicability of HZSM-5 and modify ZSM-5 for methane conversion to liquid hydrocarbons, but their research results still lead to low conversion, low selectivity and low heat resistance. The modified HZSM-5, by loading with tungsten (W), could enhance its heat resistant performance, and the high reaction temperature (800℃) did not lead to a loss of the W component by sublimation. The loading of HZSM-5 with tungsten and copper (Cu) resulted in an increment in the methane conversion as well as CO2 and C5 selectivities. In contrast, CO, C2-3 and H2O selectivities were reduced. The process of converting methane to liquid hydrocarbons (C5 ) was dependent on the metal surface area and the acidity of the zeolite. High methane conversion and C5 selectivity, and low H2O selectivity are obtained over W/3.0Cu/HZSM.     

Dealuminated ZSM-5 Zeolite Catalyst for Ethylene Oligomerization to Liquid Fuels

Ethylene oligomerization using ZSM-5 zeolite was investigated to study the role of Bronsted acid sites in the formation of higher hydrocarbons. The oligomerization of olefins, dependent on the acidity of ZSM-5 zeolite, is an important step in the conversion of natural gas to liquid fuels. The framework Si/Al ratio reflects the number of potential acid sites and the acid strength of the ZSM-5 catalyst. ZSM-5 with the mole ratio SiO2/Al2O3 equal to 30 was dealuminated for different periods of time according to the acidic ion-exchange method to produce ZSM-5 with various Si/Al ratios. The FT-IR analysis revealed that the integrated framework aluminum band, non-framework aluminum band, and silanol groups areas of the ZSM-5 zeolites decreased after being dealuminated. The performance of the dealuminated zeolite was tested for ethylene oligomerization. The results demonstrated that the dealumination of ZSM-5 led to higher ethylene conversion, but the gasoline selectivity was reduced compared to the performance     

The mass spectral fragmentation of copper(II) complexes of cyclic β-diketones

Summary Electron impact mass spectra of several bis(2-trifluoroacetylcycloalkanonato) copper(II) and bis(2-acetylcycloalkanonato) copper(II) chelates, in which the cyclic -diketonate moiety comprises five-, six-, seven-, and eight-membered ring systems, have been recorded. Compared with other copper(II) chelates of acyclic -diketonates, the present series of copper(II) cyclic -diketonates exhibited more pronounced intramolecular reduction reactions accompanied by a remarkably facile hydrogen migration resulting in the formation of the [LCu^(I)-H]⁺ ion as the base peak in all complexes investigated. The proposed fragmentation pathways leading to the formation of a number of important copper-containing daughter ions have been confirmed by metastable scanning of the corresponding parent ion spectra using the defocusing technique.

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Massenspektroskopische Fragmentierung von Kupfer(II)-Komplexen cyclischer -Diketone

Zusammenfassung Es wurden die EI-Massenspektren einiger Bis(2-trifluoracetylcycloalkanato)kupfer(II)-und Bis(2-acetylcycloalkanato)kupfer(II)-Chelate mit fünf-, sechs-, sieben- und achtgliedrigen cyclischen -Diketonat-Liganden gemessen. Im Vergleich zu anderen Kupfer(II)-Chelaten mit offenkettigen -Diketonaten zeigen die cyclischen Komplexe eine ausgeprägte Neigung zu intramolekularen Reduktionsreaktionen, die von einer bemerkenswert leicht erfolgenden Wasserstoffwanderung begleitet sind; dies führt zur Bildung von [LCu^(I)-H]⁺ als Basispeak für alle untersuchten Komplexe. Die vorgeschlagenen Fragmentierungswege, die zur Bildung einer Reihe wichtiger kupferhaltiger Tochterionen führen, wurden durch Untersuchung der entsprechenden metastabilen Mutterionen mittels der Defokussierungsmethode überprüft.

     

Co-Generation of C2 Hydrocarbons and Synthesis Gases from Methane and Carbon Dioxide： a Thermodynamic Analysis

This paper deals with thermodynamic chemical equilibrium analysis using the method of direct minimization of Gibbs free energy for all possible CH4 and CO2 reactions. The effects of CO2/CH4 feed ratio, reaction temperature, and system pressure on equilibrium composition, conversion, selectivity and yield were studied. In addition, carbon and no carbon formation regions were also considered at various reaction temperatures and CO2/CH4 feed ratios in the reaction system at equilibrium. It was found that the reaction temperature above 1100 K and CO2/CH4 ratio=1 were favourable for synthesis gas production with H2/CO ratio unity, while carbon dioxide oxidative coupling of methane （CO2 OCM） reaction to produce ethane and ethylene is less favourable thermodynamically. Numerical results indicated that the no carbon formation region was at temperatures above 1000 K and CO2/CH4 ratio larger than 1.     

Tualang honey protects keratinocytes from ultraviolet radiation-induced inflammation and DNA damage(†)

Malaysian tualang honey possesses strong antioxidant and anti‐inflammatory properties. Here, we evaluated the effect of tualang honey on early biomarkers of photocarcinogenesis employing PAM212 mouse keratinocyte cell line. Keratinocytes were treated with tualang honey (1.0%, v/v) before a single UVB (150 mJ cm^?2) irradiation. We found that the treatment of tualang honey inhibited UVB‐induced DNA damage, and enhanced repair of UVB‐mediated formation of cyclobutane pyrimidine dimers and 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine. Treatment of tualang honey inhibited UVB‐induced nuclear translocation of NF‐κB and degradation of IκBα in murine keratinocyte cell line. The treatment of tualang honey also inhibited UVB‐induced inflammatory cytokines and inducible nitric oxide synthase protein expression. Furthermore, the treatment of tualang honey inhibited UVB‐induced COX‐2 expression and PGE2 production. Taken together, we provide evidence that the treatment of tualang honey to keratinocytes affords substantial protection from the adverse effects of UVB radiation via modulation in early biomarkers of photocarcinogenesis and provide suggestion for its photochemopreventive potential.     

Synthesis and characterization of UV-irradiated silver/montmorillonite nanocomposites

We have successfully developed a simple method for preparing silver nanoparticles (Ag NPs) using UV irradiation of AgNO₃ in the interlamellar space of a montmorillonite (MMT) without any reducing agent or heat treatment. The properties of Ag/MMT nanocomposites were studied as a function of the UV irradiation period. UV irradiation disintegrated the Ag NPs into smaller size until a relatively stable size and size distribution were achieved. The results from UV–vis spectroscopy show that particles size of Ag NPs decrease with the increase of irradiation period. The crystalline structure of Ag NPs was determined by powder X-ray diffraction (PXRD).