Coupling mechanism of CO insertion in promoting aromatization of light alkanes

ABSTRACT The definition of a RECEPTOR* in terms of a receptive site, an executive site and a coupling mechanism, is followed by a general consideration of four binding criteria, which include hormone specificity, tissue specificity, high affinity and saturation, essential for distinguishing between specific and nonspecific binding. Experimental approaches are proposed for choosing an experimental system (either organized or soluble) and detecting the presence of protein binding sites. Techniques are then presented for evaluating the specific protein binding sites (receptors) in terms of the four criteria. This is followed by a brief consideration of how receptors may be located in cells and characterized when extracted. Finally various examples of oestrogen, androgen, progestagen, glucocorticoid and mineralocorticoid binding to their respective target tissues are presented, to illustrate how researchers have identified specific corticoid and mineralocorticoid binding in their respective target tissue receptors.

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Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

10.26434/chemrxiv.10028603.v1 ◽

2019 ◽

Author(s):

Paul Pearce ◽

Gaurav Assat ◽

Antonella Iadecola ◽

François Fauth ◽

Rémi Dedryvère ◽

...

Keyword(s):

Analytical Techniques ◽

Charge Compensation ◽

Coupling Mechanism ◽

Redox Processes ◽

Positive Electrodes ◽

X Ray ◽

Electrochemical Cycling ◽

Li Ion ◽

Electrochemical Instability ◽

High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

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Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

10.26434/chemrxiv.10028603 ◽

2019 ◽

Author(s):

Paul Pearce ◽

Gaurav Assat ◽

Antonella Iadecola ◽

François Fauth ◽

Rémi Dedryvère ◽

...

Keyword(s):

Analytical Techniques ◽

Charge Compensation ◽

Coupling Mechanism ◽

Redox Processes ◽

Positive Electrodes ◽

X Ray ◽

Electrochemical Cycling ◽

Li Ion ◽

Electrochemical Instability ◽

High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

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Highly active carbon nanotube–promoted Rh-Mn-Li/SiO2 catalysts for the synthesis of C2+ oxygenates from syngas

Journal of Chemical Research ◽

10.1177/1747519820984728 ◽

2021 ◽

pp. 174751982098472

Author(s):

Jun Yu ◽

Ying Han ◽

Guoqing Chen ◽

Xiuzhen Xiao ◽

Haifang Mao ◽

...

Keyword(s):

Carbon Nanotubes ◽

Photoelectron Spectroscopy ◽

Co Hydrogenation ◽

X Ray ◽

Highly Active ◽

Transmission Electron ◽

Co Insertion ◽

Temperature Programmed Surface Reaction ◽

Temperature Programmed ◽

Oxygenate Synthesis

The effect of carbon nanotubes on the catalytic properties of Rh-Mn-Li/SiO2 catalysts was investigated for CO hydrogenation. The catalysts were comprehensively characterized by means of X-ray power diffraction, N2 sorption, transmission electron microscope, H2–temperature-programmed reduction, CO–temperature-programmed desorption, temperature-programmed surface reaction, and X-ray photoelectron spectroscopy. The results showed that an appropriate amount of carbon nanotubes can be attached to the surface of the SiO2 sphere and can improve the Rh dispersion. Moderate Rh-Mn interaction can be obtained by doping with the appropriate amount of carbon nanotubes, which promotes the formation of strongly adsorbed CO and facilitates the progress of CO insertion, resulting in the increase in the selectivity of C2+ oxygenate synthesis.

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Shale gas revolution: catalytic conversion of C1–C3 light alkanes to value-added chemicals

Chem ◽

10.1016/j.chempr.2021.02.002 ◽

2021 ◽

Author(s):

Xinyu Li ◽

Chunlei Pei ◽

Jinlong Gong

Keyword(s):

Shale Gas ◽

Value Added ◽

Catalytic Conversion ◽

Light Alkanes

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Highly selective separation of acetic acid and hydrochloric acid by alkylamide based on double hydrogen bond coupling mechanism

Separation and Purification Technology ◽

10.1016/j.seppur.2021.119110 ◽

2021 ◽

pp. 119110

Author(s):

Yaqiang Li ◽

Lijuan Liu ◽

Qifeng Wei ◽

Xiulian Ren ◽

Maozhong An

Keyword(s):

Hydrogen Bond ◽

Acetic Acid ◽

Hydrochloric Acid ◽

Selective Separation ◽

Coupling Mechanism ◽

Double Hydrogen

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Remote Sensing of Ecosystem Water Use Efficiency: A Review of Direct and Indirect Estimation Methods

Remote Sensing ◽

10.3390/rs13122393 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2393

Author(s):

Wanyuan Cai ◽

Sana Ullah ◽

Lei Yan ◽

Yi Lin

Keyword(s):

Remote Sensing ◽

Water Use Efficiency ◽

Analytical Model ◽

Water Use ◽

Estimation Methods ◽

Retrieval Algorithm ◽

Canopy Conductance ◽

Coupling Mechanism ◽

Indirect Methods ◽

Use Efficiency

Water use efficiency (WUE) is a key index for understanding the ecosystem of carbon–water coupling. The undistinguishable carbon–water coupling mechanism and uncertainties of indirect methods by remote sensing products and process models render challenges for WUE remote sensing. In this paper, current progress in direct and indirect methods of WUE estimation by remote sensing is reviewed. Indirect methods based on gross primary production (GPP)/evapotranspiration (ET) from ground observation, processed models and remote sensing are the main ways to estimate WUE in which carbon and water cycles are independent processes. Various empirical models based on meteorological variables and remote sensed vegetation indices to estimate WUE proved the ability of remotely sensed data for WUE estimating. The analytical model provides a mechanistic opportunity for WUE estimation on an ecosystem scale, while the hypothesis has yet to be validated and applied for the shorter time scales. An optimized response of canopy conductance to atmospheric vapor pressure deficit (VPD) in an analytical model inverted from the conductance model has been also challenged. Partitioning transpiration (T) and evaporation (E) is a more complex phenomenon than that stated in the analytic model and needs a more precise remote sensing retrieval algorithm as well as ground validation, which is an opportunity for remote sensing to extrapolate WUE estimation from sites to a regional scale. Although studies on controlling the mechanism of environmental factors have provided an opportunity to improve WUE remote sensing, the mismatch in the spatial and temporal resolution of meteorological products and remote sensing data, as well as the uncertainty of meteorological reanalysis data, add further challenges. Therefore, improving the remote sensing-based methods of GPP and ET, developing high-quality meteorological forcing datasets and building mechanistic remote sensing models directly acting on carbon–water cycle coupling are possible ways to improve WUE remote sensing. Improvement in direct WUE remote sensing methods or remote sensing-driven ecosystem analysis methods can promote a better understanding of the global ecosystem carbon–water coupling mechanisms and vegetation functions–climate feedbacks to serve for the future global carbon neutrality.

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