Experimental study on in situ dissociation kinetics of CO 2 hydrate in pure water and water/sediments systems

2021 ◽  
Vol 11 (2) ◽  
pp. 331-341
Author(s):  
Jie Wang ◽  
Airong Li ◽  
Faping Liu ◽  
Zedong Luo
Keyword(s):  
Experimental Study ◽  
Pure Water ◽  
Dissociation Kinetics ◽  
Kinetics Of

Manipulating the water dissociation kinetics of Ni3N nanosheets via in situ interfacial engineering

2019 ◽  
Vol 7 (18) ◽  
pp. 10924-10929 ◽  
Author(s):  
Shuwen Niu ◽  
Yanyan Fang ◽  
Jianbin Zhou ◽  
Jinyan Cai ◽  
Yipeng Zang ◽  
...  
Keyword(s):  
Water Dissociation ◽  
Dissociation Kinetics ◽  
Interfacial Engineering ◽  
Kinetics Of

The sluggish water dissociation kinetics of Ni3N is significantly accelerated by in situ interfacial engineering. Owing to the unique synergy between Ni3N and MoO2, Ni3N/MoO2 displays exceptional alkaline HER activity.

scholarly journals Oxygen Affinity of Transition Metal Cations: A Coherent Descriptor in Catalytic Oxygenate Transformations

2021 ◽  
Author(s):  
Huixiang Li ◽  
Peifang Yan ◽  
B.Q. Xu ◽  
Conrad Zhang
Keyword(s):  
Interaction Strength ◽  
Oxygen Affinity ◽  
Metal Cations ◽  
Intrinsic Property ◽  
Far Infrared ◽  
Dissociation Kinetics ◽  
Metal Chlorides ◽  
Glucose Isomerization ◽  
Kinetics Of

This work reports a complementary descriptor to acidity for metal cations, oxygen affinity, to scale the interaction strength of metal cations with oxygenate groups. A method for measuring oxygen affinity is developed in alkyl methylimidazolium chloride solvents using in-situ far infrared (FIR) spectroscopy. The relative oxygen affinity values of metal cations in metal chlorides with model compounds including cyclopentanol (for alcohols), cyclohexanone (for ketones), ethylene glycol diethyl ether (for ethers), and H2O are measured from the dissociation kinetics of the metal-oxygenate complexes. The concentrations of metal-chloride and metal-oxygenate complexes are determined during evaporative removal of oxygenate molecules according to the FIR absorbance of metal-Cl bonds. The oxygen affinity values are shown to reasonably account for the catalytic performances of metal cations in furfural-acetone condensation and glucose isomerization reactions. The oxygen affinity descriptor could be potentially exploited as an intrinsic property of metal cations broadly in metal chlorides and metal oxides.

FORMATION OF NICKEL NANOPARTICLES IN SOLUTIONS OF A HYDROPHILIC GRAFT COPOLYMER

2021 ◽  
Vol 43 (2) ◽  
pp. 79-94
Author(s):  
Т.B. ZHELTONOZHSKAYA ◽  
◽  
N.М. PERMYAKOVA ◽  
A.S. FOMENKO ◽  
L.R. KUNITSKAYA ◽  
...  
Keyword(s):  
Graft Copolymer ◽  
Nickel Nanoparticles ◽  
Pure Water ◽  
In Situ Synthesis ◽  
Simple Method ◽  
Resonance Band ◽  
Vis Spectroscopy ◽  
Copolymer Matrices ◽  
Kinetics Of

A graft copolymer of poly(vinyl alcohol) and polyacrylamide (PVA-g-PAAm) with interacting main and grafted chains was synthesized by radical matrix polymerization of PAAm from the PVA backbone in an aqueous medium. Its basic molecular parameters including the number and length (molecular weight) of grafts were determined using elemental analysis, DTGA and viscometry. The copolymer macromolecules formed special monomolecular micelles of elipsoidal shape and length ~18-64 nm in aqueous solutions due to the formation of intramolecular polycomplexes between the main and grafted chains. This copolymer was used as a hydrophilic matrix for the in situ synthesis of nickel nanoparticles (NiNPs) in aqueous solutions.On the basis of UV-Vis spectroscopy, an original and simple method for monitoring the kinetics of the formation and yield of metal nanoparticles in systems in which a surface plasmon resonance band does not appear has been proposed and implemented. Using this approach, the kinetics of borohydride reduction of Ni-salt to NiNPs in pure water and PVA-g-PAAm solutions was studied depending on the concentrations of Ni-salt and copolymer matrices. An increase in the initial rate of accumulation and yield of NiNPs with an increase in the concentration of Ni-salt and a decrease in both parameters in copolymer solutions in comparison with pure water was established. At the same time, the accumulation rate and NiNP yield in a complex way was depended on the matrix concentration that was determined by the ratio of such factors as a decrease in the diffusion rate of NaBH4 molecules in copolymer solutions and the accumulation of Ni2+-ions in matrix particles due to complexation with active chemical groups at the first stage of reduction process. The morphology and main structural elements of the NiNPs/PVA-g-PAAm composition were revealed using TEM. It was shown that the in situ synthesis of NiNPs in copolymer matrices was accompanied by the “detachment” of PAAm grafts from the main PVA chains and led to the appearance of two new structures, such as “hairy coils” and “hairy rods”, containing small spherical NiNPs (d~0,5–12,0 nm) in isolated and chain states, respectively. The appearance of the latter structures was explained by the formation of coordination complexes of Ni2+-ions with active groups of both PVA and PAAm chains at the first stage of the reduction reaction.

An In situ Experimental Study on Solidification Kinetics of Polyolefins: Effect of Cooling Conditions

2015 ◽  
Vol 55 (1) ◽  
pp. 99-113
Author(s):  
Bin Yang ◽  
Yan-Dong Guo ◽  
Ru Xia ◽  
Ji-Bin Miao ◽  
Li-Feng Su ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cooling Conditions ◽  
Solidification Kinetics ◽  
Kinetics Of

Influence of the supersaturation on the nucleation-growth process of scale electrodeposition by in situ observation through a transparent quartz crystal microbalance

2004 ◽  
Vol 49 (2) ◽  
pp. 145-152 ◽  
Author(s):  
O. Devos ◽  
C. Gabrielli ◽  
B. Tribollet
Keyword(s):  
Growth Process ◽  
Quartz Crystal ◽  
Pure Water ◽  
In Situ Observation ◽  
Nucleation Process ◽  
Mass Measurements ◽  
Kinetics Of ◽  
Scale Deposition ◽  
Nucleation Growth

An original technique allowed three in situ measurements to be obtained simultaneously, i.e. electrochemical and mass measurements and a microscope image of the interface between electrode and solution. The nucleation-growth process of CaCO3 deposition was investigated by varying different parameters which influenced the supersaturation coefficient, the Ca2+ concentration, pH and convection of the carbonically pure water near the substrate. The results showed that the variation of the scaling rate was due, for the two first cases, to an influence of the nucleation process whereas for the last case, the kinetics of scale deposition were modified by a shift of the growth rate.

In Situ Raman Study of the Formation and Dissociation Kinetics of Methane and Methane/Propane Hydrates

2020 ◽  
Vol 34 (5) ◽  
pp. 6288-6297
Author(s):  
Hai S. Truong-Lam ◽  
SeongDeok Seo ◽  
Suhkmann Kim ◽  
Yongwon Seo ◽  
Ju Dong Lee
Keyword(s):  
Dissociation Kinetics ◽  
In Situ Raman ◽  
Raman Study ◽  
Kinetics Of

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

Growth kinetics of Al2Cu in an Al-1.5Cu thin film by in Situ TEM

1993 ◽  
Vol 51 ◽  
pp. 1172-1173
Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson
Keyword(s):  
Thin Film ◽  
In Situ Tem ◽  
Collector Plate ◽  
Transmission Electron ◽  
Device Processing ◽  
Corrosion Susceptibility ◽  
Precipitation Phenomena ◽  
Semiconductor Chips ◽  
Kinetics Of

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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