Techniques for the kinetic study of fast reactions in solution

Kruger, H.

doi:10.1039/cs9821100227

Cited by 19 publications

(10 citation statements)

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“…11d) A condition for the uptake is therefore that the affinity of Ca 2+ ions for the H 2 O ligands is not too strong. This condition is met in this case as the water ligand “mean residence time” is of the order around 10 −8 s at room temperature,12 which is comparable to the published water exchange rate constant of 6–9⋅10 8 s −1 13a, b. 14 As [Ca(H 2 O) 6 ] 2+ shows a much greater lability compared to the related Be 2+ and Mg 2+ hydrate complexes, Be 2+ and Mg 2+ should therefore both show a different behavior with respect to their interactions with the capsule(s) 14.…”

supporting

confidence: 51%

Porous Capsules Allow Pore Opening and Closing That Results in Cation Uptake

et al. 2005

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supporting

confidence: 51%

Porous Capsules Allow Pore Opening and Closing That Results in Cation Uptake

et al. 2005

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“…Thus, Ba and Sr alkoxides hydrolyze faster upon exposure to water than the other alkoxide components. 32 , 35 This in turn enhances the olation condensation mechanism since the aqua or alcohol moieties are good leaving groups. 36 To see the effect of this on the fully formed oxide films, analysis of atomic composition of the two samples was undertaken by XPS (Figure S3, Supporting Information ).…”

Section: Resultsmentioning

confidence: 99%

High Performance, Low Temperature Solution-Processed Barium and Strontium Doped Oxide Thin Film Transistors

et al. 2014

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Amorphous mixed metal oxides are emerging as high performance semiconductors for thin film transistor (TFT) applications, with indium gallium zinc oxide, InGaZnO (IGZO), being one of the most widely studied and best performing systems. Here, we investigate alkaline earth (barium or strontium) doped InBa(Sr)ZnO as alternative, semiconducting channel layers and compare their performance of the electrical stress stability with IGZO. In films fabricated by solution-processing from metal alkoxide precursors and annealed to 450 °C we achieve high field-effect electron mobility up to 26 cm2 V–1 s–1. We show that it is possible to solution-process these materials at low process temperature (225–200 °C yielding mobilities up to 4.4 cm2 V–1 s–1) and demonstrate a facile “ink-on-demand” process for these materials which utilizes the alcoholysis reaction of alkyl metal precursors to negate the need for complex synthesis and purification protocols. Electrical bias stress measurements which can serve as a figure of merit for performance stability for a TFT device reveal Sr- and Ba-doped semiconductors to exhibit enhanced electrical stability and reduced threshold voltage shift compared to IGZO irrespective of the process temperature and preparation method. This enhancement in stability can be attributed to the higher Gibbs energy of oxidation of barium and strontium compared to gallium.

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“…As a consequence, Cr(III) ions produce amorphous gels whose compositions range from Cr(OH) 3 37,38 . In all cases, the kinetics of polymerization in an aqueous medium strongly depend on the charge, size, electronegativity and electronic configuration of the metallic ion 39,40 : the smaller the charge and the larger the ionic radius the faster will be the process. As a consequence, the dimerization rate constant of the Fe(III) precursor is rather low (k = 10 -1 -10…”

Section: Discussionmentioning

confidence: 99%

Chromium and Copper-Doped Magnetite Catalysts for the High Temperature Shift Reaction

Quadro¹,

Dias²,

Amorim³

et al. 1999

J. Braz. Chem. Soc.

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Foi obtida magnetita pura e dopada com cromo e cobre, visando produzir catalisadores, na fase ativa, destinados à conversão de monóxido a dióxido de carbono a altas temperaturas (reação de HTS). As amostras foram preparadas por aquecimento do hidroxoacetato de misto ferro (III), IHA, na faixa de 150-400 °C, e caracterizados por análise química, difração de raios-X, análise térmica (DSC e TG), espectroscopia no infravermelho, medidas de área específica, microscopia eletrônica de varredura e microssonda eletrônica de raios X. Observou-se que a presença do cobre favorece a formação da magnetita mas não afeta a cristalinidade dos sólidos, de modo significativo. Ambos os dopantes melhoram o desempenho dos catalisadores: o cromo atua como estabilizador, enquanto o cobre aumenta a atividade intrínseca. Entretanto, este último favorece a sinterização, levando à formação de sólidos com baixas áreas superficiais. O efeito sinérgico desses dopantes é aumentar a atividade catalítica e a área superficial dos sólidos.Copper and chromium-doped magnetite was prepared to be used as catalysts, in the active phase, in the high temperature shift (HTS) reaction. Samples were produced by heating a mixed hydrate ferric oxyhydroxide (IHA) in the range of 150-400 °C and characterized by means of chemical analysis, X-ray diffraction, thermal analysis (DSC and TG), infrared spectroscopy, surface area measurements, scanning electron microscopy and X-ray microanalysis. It was found that copper favors magnetite formation but does not affect significantly the crystallinity of the solids. Both chromium and copper improve the performance of the catalysts towards the HTS reaction: chromium acts as a stabilizer whereas copper increases the intrinsic activity. However, copper favors sinterization leading to solids with low surface areas. The increase in the catalytic activity and in the surface area of the solids reflects the synergy of these dopants.

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Techniques for the kinetic study of fast reactions in solution

Cited by 19 publications

References 0 publications

Porous Capsules Allow Pore Opening and Closing That Results in Cation Uptake

Porous Capsules Allow Pore Opening and Closing That Results in Cation Uptake

High Performance, Low Temperature Solution-Processed Barium and Strontium Doped Oxide Thin Film Transistors

Chromium and Copper-Doped Magnetite Catalysts for the High Temperature Shift Reaction

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