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1.
Samples of [Ni4Al(OH)10]OH were prepared by co-precipitation with the existence of calcium and subsequent hydrothermal treatment. Inductively coupled
plasma (ICP) measurements show that the composition of prepared samples does not change very much with the initial concentration
of Ca2+ in the mother solution, which may be related to the high solubility of Ca(OH)2. Powder X-ray diffraction measurements show that the modification does not change the lattice parameters of [Ni4Al(OH)10]OH a lot, but scanning electron microscope images show some morphological differences between the sample without Ca and the
sample after the modification of calcium hydroxide. However, those changes in composition and morphology do improve the reversibility
and charge efficiency of [Ni4Al(OH)10]OH, especially at a higher temperature of 65 °C. For example, the difference between the oxidation peak and oxygen evolution
peak in the cyclic voltammetric diagrams at 65 °C becomes large, a better charge/discharge performance at high current density
can be observed. In addition, the charge-transfer resistance (R
t) of the electrode according to the electrochemical impedance spectra increases after the modification of calcium and become
larger as the temperature is elevated for 20 to 65 °C. 相似文献
2.
On the Sodium Tetrahydroxoaluminate Chloride Na2[Al(OH)4]Cl The hitherto unknown compound Na2[Al(OH)4]Cl was prepared by crystallisation from a NaCl containing sodium aluminate solution. According to the X-ray single crystal investigation (tetragonal, space group P4/nmm, a = 7.541 Å, c = 5.059 Å, Z = 2) the compound represents the first example of a crystalline hydroxoaluminate with monomeric [Al(OH)4]? anions. Cl? shows a quadratic anti prismatic coordination to 4 Na+ and over hydrogen bonds to 4 O2? while Na+ is octahedrally coordinated by 4 O2? and 2 Cl? (axial). The results of the crystal structure analysis are confirmed by 27Al and 23Na MAS NMR investigations. Na2[Al(OH)4]Cl decomposes at about 200°C without intermediates under formation of β-NaAlO2 and NaCl. 相似文献
3.
Hydroxo Compounds. 10. The Sodium Oxohydroxostannates(II) Na4[Sn4O(OH)10] and Na2[Sn2O(OH)4] Na4[Sn4O(OH)10] = Na4[Sn(OH)3]2[Sn2O(OH)4] ( I ) and Na2[Sn2O(OH)4] ( II ) have now been doubtlessly characterized as the first Na-hydroxostannates(II). I crystallizes monoclinic in P21/n (a = 1522.4(5) pm, b = 830.0(2) pm, c = 1276.0(3) pm, β = 104.8(2)°, Z = 4, R = 0.047, 1137 Ihkl); II crystallizes orthorhombic in P212121 (a = 1450(2) pm, b = 1665(2) pm, c = 590.7(8) pm, Z = 8, R = 0.042, 1208 Ihkl). II is identical with the compound which was described up to now as “Na[Sn(OH)3]”. The new compounds contain the complex anions [Sn(OH)3]? and [Sn2O(OH)4]2?, whose structures are now proved. The oxotetrahydroxo-distannate(II) anion [Sn2O(OH)4]2? exhibits a syn-conformation with respect to the projection along the (Sn? Sn) vector. The two compounds crystallize with pronounced layer structures, which show direct topotactical relations with one another as well as with SnO. This relates closely to the fast formation of SnO from crystals of I and II . 相似文献
4.
[Me4N]10[Fe4(OH)4(PW10O37)2] · 15H2O was synthesized by the reaction of FeCl3 ·6H2O, with △-Na8HPW9O34 and Me4NBr. Crystal data: M = 6225.75, space group P21/c with the monoclinic parameters: a = 1.3228(5), b = 3.5634(3), c = 1.5226(2) nm, β = 94.20(2)°, V = 7.1576nm3, 7 = 2,DC = 2.888 g/cm3, Mo Kαradiation (λ = 0.071069 nm), μ= 168.534 cm-1, F(000)=5576, final R = 0.0428 and Rw = 0.1204 for 7086 observed reflections with I > 2σ( I) . The structure of the title compound is the first structurally characterized heteropolymetalate with hydroxo-bridging metal aggregation Fe4OH4 encapsulated in the dimer of Keggin polyoxoanion. 相似文献
5.
Murrie M Biner D Stoeckli-Evans H Güdel HU 《Chemical communications (Cambridge, England)》2003,(2):230-231
The role of temperature in the formation of high nuclearity nickel(II) citrate spin clusters is explored, revealing how changes in structure and hence magnetic properties can be triggered through desolvation and ligand reorganisation. 相似文献
6.
M. J. Hernández M. A. Ulibarri J. Cornejo 《Journal of Thermal Analysis and Calorimetry》1986,31(3):633-641
The kinetics of thermal dehydration of [Ni2Al(OH)6]2SO4.nH2O has been studied through the analysis of isothermal weight loss data. The results obtained seem to indicate that the process is governed by a diffusion mechanism up to an value which is dependent on the temperature. An explanation is provided for this behaviour on the basis of the structural properties of the compound and the nature of the water loss.
Zusammenfassung Die Kinetik der thermischen Dehydratisierung von [Ni2Al(OH)6]2SO4.nH2O wurde mittels isothermer TG untersucht. Die Ergebnisse scheinen darauf hinzudeuten, daß der Prozeß bis zu einem von der Temperatur abhängigen -Wert von einem Diffusionsmechanismus bestimmt wird. Für dieses Verhalten wird basierend auf den strukturellen Eigenschaften der Verbindung und der Natur der Wasserabgabe eine Erklärung gegeben.
, [Ni2Al(OH)6]2SO4.nH2O. , , . , .相似文献
7.
A novel zinc borophosphate Zn[BPO(4)(OH)(2)] with moganite-type topology (a rare polymorph of silica) has been prepared from a mixture of ZnO, B(2)O(3), and P(2)O(5) by hydrothermal treatment at 443 K. The crystal structure was determined from single-crystal X-ray data (orthorhombic, Pbcn (no. 60), a=915.07(3), b=897.22(3), c=1059.19(3) pm, V=869.62(5)x10(6) pm(3), Z=8, R1=0.028, wR2=0.075). The crystal structure comprises unbranched vierer-single borophosphate chains running along [010] and interconnected via ZnO(2)(OH)(2)-tetrahedra by sharing common vertices. The resulting topology of the three-dimensional tetrahedral framework structure is described by the Schl?fli symbol (4(2).6(2).8(2))(4.6(4).8)(2). Although showing Zn in a tetrahedral coordination, the title compound does not belong to the group of zincoborophosphates but is a special case of a borophosphate containing vierer single rings of tetrahedra with the sequence Zn-B-Zn-P. 相似文献
8.
Agnieszka Kapałka Audrey Cally Stefano Neodo Christos Comninellis Michael Wächter Kai M. Udert 《Electrochemistry communications》2010,12(1):18-21
The electrochemical oxidation of ammonia was investigated on a Ni/Ni(OH)2 electrode prepared by potential cycling of a Ni electrode in 1 M NaClO4. It was found that oxidation of ammonia is strongly pH dependent and proceeds mainly at pH values above 7. This indicates that NH3 rather than is oxidized on nickel electrodes. Oxidation of ammonia occurs in the potential region of Ni(II)/Ni(III) redox activity resulting in formation of a clear peak. Ni/Ni(OH)2 is not deactivated during ammonia oxidation even at high ammonia concentrations. A considerable fraction of the ammonia was oxidized to nitrate (11%), while the rest were gaseous nitrogen compounds. It is postulated that nitrogen was formed via a mechanism involving direct electron transfer from ammonia to the anode whereas the formation of nitrate involved oxygen transfer from water to an ammonia molecule. 相似文献
9.
Jun Zhang Lingzhi Shangguan Shaomin Shuang Chuan Dong 《Russian Journal of Electrochemistry》2013,49(9):888-894
A nickel hydroxide-modified nickel electrode (Ni(OH)2/Ni) was successfully prepared by the cyclic voltammetry (CV) method and the electrocatalytic properties of the electrode for formaldehyde and methanol oxidation have been investigated respectively. The Ni(OH)2/Ni electrode exhibits high electrocatalytic activity in the reaction. A new method has been developed for formaldehyde determination at the nickel hydroxide-modified nickel electrode and the experimental parameters were optimized. The oxidation peak current is linearly proportional to the concentration of formaldehyde in the range of 7.0 × 10?5 to 1.6 × 10?2 M with a detection limit of 2.0 × 10?5 M. Recoveries of artificial samples are between 93.3 and 103.5%. The effect of scan rate and methanol concentration on the electrochemical behavior of methanol were investigated respectively. 相似文献
10.
Wei Song Guangjie Shao Guiling Wang Zhipeng Ma Shuang Liu Jianjun Song Caixia Wang 《Journal of Solid State Electrochemistry》2014,18(11):3173-3180
Ni(OH)2 was compounded to MnO2 in an easy liquid phase process to improve the diffusion process of the electrode. The as-prepared materials were a mixture of amorphous and nanocrystalline with aggregated nanoparticles forming slit-shaped pore structures. The composite has higher specific surface area and smaller pore volume compared with pristine MnO2. Electrochemical properties of the electrodes were carried out with cyclic voltammetry (CV), galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy (EIS). The MnO2/Ni(OH)2 composites exhibited enhanced electrochemical properties than that of pristine MnO2. Remarkably, the composite which contains 3 % Ni(OH)2 exerted the best discharged specific of 408 F g?1 under 0.2 A g?1, much higher than 247 F g?1 of pristine MnO2 at the same current density. Better rate capability and cycling stability were also realized by the same composite in comparison. 相似文献
11.
A new ligand capable of producing calcium-selective electrodes with excellent characteristics is presented. The ligand (1) is a calix[4]arene bearing phosphine oxide ligating groups on the lower rim and this is the first report that such ligands can discriminate in favour of calcium ions against magnesium ions and the alkali metal ions. This calcium selectivity is in complete contrast to the behaviour of the well-known calix[4]arene tetraester derivatives (such as 2) which are selective for sodium against other alkali metal ions and group II ions. Electrodes based on PVC membranes incorporating ligand 1 display almost nernstian slopes and excellent selectivity against common interferants, including magnesium (log K(Ca,Mg)(pot)). The electrodes have demonstrated effective lifetimes of at least 7 weeks (duration of the study) and very fast response times. 相似文献
12.
《无机化学与普通化学杂志》2018,644(1):50-57
To provide a better understanding of the recently published pure metalorganic NiI species, [Ni(cod)2][Al(ORF)4] ( 1 ) [cod = 1,5‐cyclooctadiene, RF = C(CF3)3], further characterizations were performed and analyzed. Thus, the solvation of 1 in THF was examined by EPR, surprisingly disclosing the initiation of a disproportionation reaction to [NiII(THF)6][Al(ORF)4]2 ( 3 ) and Ni0. Further studies concerning the ability of 1 to activate small molecules exhibit the formation of a remarkable [Ni3S2(cod)3]2+ cluster ( 5 ) in an oxidation reaction with S8, while EPR measurements of the resulting product in a reaction with oxygen indicate a possible coordination of O2. Single crystal X‐ray structures as well as spectroscopic analyses of 3 and 5 are described. 相似文献
13.
Platinum electrodes modified with Mn(II) 5-(N-(8-pyrrole-yl-3,6-dioxa-1-aminooctane)phenylamide-10,15,20-trimethoxyphenylporphyrin (Mn(II)triOMeTCPPyP) using multi-sweep cyclic voltammetry and differential pulse amperometry were evaluated as electrocatalytic surfaces for the oxidation of nitric oxide. The electrodes modified using the pulse amperometric approach were more sensitive towards the detection of nitric oxide. The increased sensitivity led to the attainment of a wider linear dynamic range for the quantification of nitric oxide. 相似文献
14.
Jan Ellermeier Ralph Sthler Wolfgang Bensch 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m70-m73
Both title compounds, bis[tris(2‐aminoethyl)amine]nickel(II) dichloride, [Ni(tren)2]Cl2, (I), and bis[tris(2‐aminoethyl)amine]nickel(II) tetrathiotungstate, [Ni(tren)2]WS4, (II), contain the [Ni(tren)2]2+ cation [tren is tris(2‐aminoethyl)amine, C6H18N4]. The tren molecule acts as a tridentate ligand around the central Ni atom, with the remaining primary amine group not bound to the central atom. In (I), Ni2+ is located on a centre of inversion surrounded by one crystallographically independent tren molecule. In the [Ni(tren)2]2+ cation of (II), the Ni atom is bound to two crystallographically independent tren molecules. The Ni atoms in the [Ni(tren)2]2+ complexes are in a distorted octahedral environment consisting of six N atoms from the chelating tren molecules. The counter‐ions are chloride anions in (I) and the tetrahedral [WS4]2? anion in (II). Hydrogen bonding is observed in both compounds. 相似文献
15.
The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM−1, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e− and 2H+ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability. 相似文献
16.
The reaction of ZrCl4 with [gamma-SiW10O36]8- in a potassium acetate buffer results in two different products depending on the reactant ratios. The trimeric species [Zr6O2(OH)4(H2O)3(beta-SiW10O37)3]14- (1) consists of three beta23-SiW10O37 units linked by an unprecedented Zr6O2(OH)4(H2O)3 cluster with C1 point group symmetry. The dimeric species [Zr4O2(OH)2(H2O)4(beta-SiW10O37)2]10- (2) consists of beta22- and beta12-SiW10O37 units sandwiching a Zr4O2(OH)2(H2O)4 cluster, which also has C1 symmetry. Polyanion 1 contains more zirconium centers than any other polyoxometalate known to date. 相似文献
17.
O. A. Plyusnina V. A. Emel’yanov I. A. Baidina I. V. Korol’kov S. A. Gromilov 《Journal of Structural Chemistry》2007,48(1):114-121
Double complex [RuNO(NH3)4OH][PtCl4] (I) and [RuNO(NH3)4OH][PdCl4] (II) salts have been prepared and explored with TGA, IR spectroscopy, powder and single crystals X-ray diffraction. Crystal phases
of I and II are isostructural (space group Cmc21) and have the following crystal chemical characteristics: a = 8.106 Å, b = 18.190(3) Å, c = 8.097 Å, V = 1194.0 Å3, Z = 4, ρcalc = 3.077 g/cm3 (I), and a = 8.116 Å, b = 18.135 Å, c = 8.062 Å, V = 1186.5 Å3, Z = 4, ρcalc = 2.600 g/cm3 (II). The product of thermal decomposition of I in inert and hydrogen atmospheres is a substitution solid solution Pt0.5Ru0.5 with the parameter of the FCC unit cell a = 3.856(3) Å. Thermolysis of II affords two-phase mixtures of limited solid solutions of the metals featuring Ru-based HCP and Pd-based FCC cells.
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Translated from Zhurnal Strukturnoi Khimii, Vol. 48, No.1, pp.114–121, January–February, 2007. 相似文献
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The oligoalumosiloxanes {[Ph2SiO]8[Al(O)OH]4·2,5Et2O·HOtBu} ( 6 ) and {[Ph2SiO]8[Al(O)OH]4·2Et2O·2HOiPr} ( 7 ) have been obtained from the reaction of diphenylsilanediol with aluminium‐tri‐tert‐butoxide and aluminium‐tri‐iso‐propoxide in ethyl ether with reasonable yields. In a 1:1 molar mixture of toluene and the respective alcohol (iso‐propanol or tert‐butanol), the ethyl ether molecules in {[Ph2SiO]8[Al(O)OH]4·4Et2O}, in 6 or 7 can be completely displaced forming the compounds [Ph2SiO]8[Al(O)OH]4·4HOiPr ( 8 ) and [Ph2SiO]8[Al(O)OH]4·nHOtBu ( 9 ). Whereas 6 , 7 and 8 are crystalline, 9 is obtained as a viscous liquid. An X‐ray structure determination on {[Ph2SiO]8[Al(O)OH]4·3Et2O·HOtBu} reveals different bonding modes of the diethyl ether molecules to the oligoalumosiloxane compared to the tert‐butanol, which forms two hydrogen bonds (one to the OH‐group of the inner Al4(OH)4 cycle and one through the alcohol OH‐group to a Si–O–Al moiety. The alcohol adducts have been characterized in solution through 1H‐, 13C‐ and 29Si‐NMR and show dynamic equilibria between the oligoalumosiloxane [Ph2SiO]8[Al(O)OH]4 and the alcohol molecules. 相似文献