Sol-gel spin coated well adhered MoO3 thin films as an alternative counter electrode for dye sensitized solar cells

In this work, we aim to develop a viable, inexpensive and non-toxic material for counter electrodes in dye sensitized solar cells (DSSCs). We employed an ultra-simple synthesis process to deposit MoO₃ thin films at low temperature by sol-gel spin coating technique. These MoO₃ films showed good transparency. It is predicted that there will be 150 times reduction of precursors cost by realizing MoO₃ thin films as a counter electrode in DSSCs compared to commercial Pt. We achieved a device efficiency of about 20 times higher than that of the previous reported values. In summary we develop a simple low cost preparation of MoO₃ films with an easily scaled up process along with good device efficiency. This work encourages the development of novel and relatively new materials and paves the way for massive reduction of industrial costs which is a prime step for commercialization of DSSCs.     

Physical properties of molybdenum monoboride: Ab-initio study

The Ab initio investigations on structural, electronic, optical and thermal properties of MoB have been reported using full potential linearised-augmented plane wave method within the framework of density functional theory. The exchange and correlation potentials were calculated using the Perdew-Burke-Ernzerhof-Sol generalised gradient approximation. The calculated equilibrium lattice constants and cell volume are in excellent agreement with the experimental results as compared to the available theoretical data. Electronic band structure shows that MoB is metallic in nature. From the partial densities of states of MoB it has been found that major contribution on the Fermi level is due to Mo-4d states. Among the reported optical parameters the large value of reflectivity at low energy shows that MoB can be used as a coating material in IR region. Maximum absorption in extreme UV region shows that it can be used in production of electricity through solar power in space vehicles. Various thermal properties have been calculated in a wide temperature range at high pressures. Change in thermal expansion coefficient with respect to temperature shows that anharmonic effect in MoB is very weak at high temperature. The optical and thermal properties of MoB are presented for the first time in this work.     

The First Molybdenum Oxo‐iodide Cluster – [Mo4OI12]2–

Reaction of Mo(CO)₆ with Bu₄NI and I₂ in diglyme yielded a new butterfly Mo^III cluster [Mo₄OI₁₂]^2–. The structure of tetraphenylphosphonium salt was determined by X‐ray single crystal diffraction. Ph₄P⁺ and Bu₄N⁺ salts were further characterized by elemental analysis, mass spectrometry, energy‐dispersive X‐ray (EDX), IR, Raman, and UV/Vis spectroscopy and CVA studies. The cluster anion has a butterfly array of molybdenum atoms and can be represented as [Mo₄(μ₄‐O)(μ₃‐I)₂(μ₂‐I₄)I₆]^2–.     

Kinetic–catalytic–spectrophotometric determination of low concentrations of molybdenum in white wines

The paper describes the determination of the molybdenum content in white wines based on its catalytical action on the kalium iodide oxidation by hydrogen peroxide in acid medium.

The optimum reaction conditions (the catalyst, KI and H₂O₂ concentrations, the pH value, the order of the reagent additions, the temperature) have been found by studying the effect of the reaction variables.

The influence of some metallic ions (Ca²⁺, Mg²⁺, Zn²⁺, Cd²⁺, Fe²⁺ and Fe³⁺) and complexing anions (F⁻, C₂O²⁻₄, EDTA⁴⁻) on the catalyzed reaction rate was elucidated.

The molybdenum concentration was estimated by the tangent, fixed-time and fixed-absorbance method. The obtained average values for molybdenum content in white wines are within the 1.77×10⁻⁷–1.83×10⁻⁷ mol l⁻¹ range.     

Ligand substitution kinetics in M(CO)4(η-norbornadiene) complexes (M=Cr, Mo, W): displacement of norbornadiene by bis(diphenylphosphino)alkanes

The thermal substitution kinetics of norbornadiene (NBD) by bis(diphenylphosphino)alkanes (PP), (C₆H₅)₂P(CH₂)_nP(C₆H₅)₂ (n=1, 2, 3) in M(CO)₄(η^2:2-NBD) complexes (M=Cr, Mo, W), were studied by quantitative FT-IR spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of the leaving NBD ligand and on the concentration and the nature of the entering PP ligand. In the proposed mechanism there are two competing initial steps: an associative reaction involving the attachment of the entering PP ligand to the transition metal center and a dissociative reaction involving the stepwise detachment of the diolefin ligand from the transition metal center. A rate law is derived from the proposed mechanism. The activation parameters are obtained from the evaluation of the kinetic data. It is found that at higher concentrations of the entering ligand, the associative path is dominant, while at lower concentrations the contribution of the dissociative path becomes significant. Both the observed rate constant and the activation parameters show noticeable variation with the chain length of the diphosphine ligand.     

Synthesis and characterization of oxo---imido and alkyl---imido complexes of molybdenum(VI)

Treatment of the complex Mo(Nmes)(O)Cl₂(dme) (mes=2,4,6-trimethylphenyl; dme=1,2-dimethoxyethane) with KTp^Me2, NaCp and bipy gives the corresponding derivatives (Tp^Me2)Mo(Nmes)(O)Cl (1), CpMo(Nmes)(O)Cl (2) and Mo(Nmes)(O)Cl₂(bipy) (3). Other oxo---imido compounds of composition Mo(Nmes)(O)(S₂CNR₂)₂ (R₂=C₄H₄ 4, C₅H₁₀ 5, ⁱPr₂ 6) can be obtained by reacting Mo(Nmes)(O)Cl₂(dme) with the appropriate dithiocarbamate salt. The NMR properties of 4–6 are consistent with the presence of two rapidly equilibrating dithiocarbamate ligands. The reaction of Mo(Nmes)(O)Cl₂(dme) with different Grignard reagents, Mg(R)X, produces the trialkyl imido complexes Mo(Nmes)R₃Cl (R=Me 7, CH₂C(Me)₂Ph 8, CH₂SiMe₃ 9).     

催化极谱法测定产妇、新生儿全血和胎盘中的微量钼

在０－２２５ ｍｏｌ／ＬＨ２ＳＯ４ － ０－２５ ％ 苯羟乙酸－ ３ ％ ＫＣ１Ｏ３ 底液体系中, 钼有一个灵敏的极谱催化波, 用于测定临床样品中的Ｍｏ , 其峰电位－ ０－３０ Ｖ（ 对Ｓ－Ｃ－Ｅ） 。２３ 种共存离子的含量低于允许存在量, 不干扰测定。方法的检出限１－４ ×１０ － １０ ｇ／ｍＬ, 线性范围０－００１ ～０－５００ ｍｇ／Ｌ, １１ 次测定的相对标准偏差为１－８９ ％ ～３－４２ ％ , 标准回收率９７－２ ％ ～１０２－８ ％ 。方法简便、快速。测定了西宁市３５ 例分娩孕妇全血、新生儿脐血和胎盘中的钼, 获得了理想的结果。     

Mo-La2O3模拟阴极的高温XPS/AES研究Ⅰ. 表面氧状态及其性质

对稀土氧化物体系Ｌａ２Ｏ３中Ｏｌｓ的超高温原位ＸＰＳ进行研究,着重讨论了Ｍｏ－Ｌａ２Ｏ３阴级激活过程中温度变化导致表面氧状态改变的过程,并初步分析其对电子发射性能的影响。高温１３００℃以上,存在两类不同氧种的氧,低结合能端的氧是表面晶格氧,高结合能端的氧为吸附氧;     

Kaliumtetrachlorooxomolybdat(V), KMoOCl4

Potassium Tetrachlorooxomolybdate(V), KMoOCl₄ KMoOCl₄ was obtained at 200 °C in small yield as a side‐product from the reaction of S₂Cl₂ with molybdenum which contained 0.7% of potassium (the main product was MoS₂Cl₃). Attempts to increase the yield by adding stoichiometric amounts of KOH or of KCl + H₂O failed. An attempt to produce KMoOCl₄ by the reduction of MoOCl₄ with KI yielded K₃Mo₂Cl₉ and a small amount of K₂MoOCl₅. The crystal structure of KMoOCl₄ is monoclinic, space group P2₁/c, a = 657,1; b = 901,6; c = 2327,3 pm; β = 92,81°, Z = 8. Square‐pyramidal MoOCl₄^– ions are associated to infinite zigzag chains by Mo…Cl contacts.     

Sulfinylamid-Metathese und Nitren-Transfer an Komplexen des sechswertigen Molybdäns und Wolframs

Sulfinylamide Metathesis and Nitrene Transfer at Complexes of Hexavalent Molybdenum and Tungsten Protolysis of tungsten hexachloride with tosyl amide offers a direct access to [W(NTos)₂Cl₂]_n ( 1 a) . In presence of donor ligands coordination polymer 1 a can be converted into molecular complexes, e. g. [W(NTos)₂Cl₂(dme)] ( 1 b ), [W(NTos)₂Cl₂(PMe₃)₂] ( 1 c ) and [W(NTos)₂Cl₂(4,4′-Me₂bipy)] ( 1 d ). The synthesis of the homologous molybdenum compound [Mo(NTos)₂Cl₂]_n ( 2 a) can be achieved via metathesis of [Mo(O)₂Cl₂]_n with sulfinyl amide Tos-NSO. An attempt to synthesize a molybdenum phosphine complex in an analogous manner as 1 c , but starting from 2 a or its base adduct [Mo(NTos)₂Cl₂(dme)] ( 2 b ), leads to nitrene transfer to the phosphine. Me₃P=NTos can be detected and the d² molybdenum complex [Mo(NTos)Cl₂(PMe₃)₃] ( 3 ) is isolated. 3 is characterized by a crystal structure analysis. In phosphine complex 1 c , a similar nitrene abstraction is inhibited, in contrast 1 d is reacting with PMe₃ under nitrene abstraction to yield [W(NTos)Cl₂(4,4′-Me₂bipy)(PMe₃)₂] ( 4 ). This observation is in accord with a nitrene transfer induced via direct attack of the phosphine on the nitrogen atom of 1 d .