The Experts below are selected from a list of 21303 Experts worldwide ranked by ideXlab platform
Bert M. Weckhuysen - One of the best experts on this subject based on the ideXlab platform.
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Probing the influence of X-rays on aqueous copper solutions using time-resolved in situ combined video/X-ray absorption near-edge/Ultraviolet-Visible Spectroscopy.
The journal of physical chemistry. B, 2006Co-Authors: J. Gerbrand Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.
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probing the influence of x rays on aqueous copper solutions using time resolved in situ combined video x ray absorption near edge Ultraviolet Visible Spectroscopy
Journal of Physical Chemistry B, 2006Co-Authors: Gerbrand J Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.
Leonard J. Barbour - One of the best experts on this subject based on the ideXlab platform.
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Single-Crystal to Single-Crystal Uptake of Volatile Solids and Associated Chromatic Response in a Porous Metallocycle.
Inorganic chemistry, 2018Co-Authors: Marike Du Plessis, Varvara I. Nikolayenko, Leonard J. BarbourAbstract:Guest molecules have been absorbed into crystals of a metallocyclic host by sublimation of volatile solids at room temperature. The guest exchanges are accompanied by color changes. Since the crystals remain intact, evidence of guest inclusion could be obtained using single-crystal X-ray diffraction. The results are also supported by thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), Fourier transform infrared Spectroscopy (FT-IR), and Ultraviolet–Visible Spectroscopy (UV–vis).
Atsushi Urakawa - One of the best experts on this subject based on the ideXlab platform.
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Unravelling the Role of Oxygen Vacancies in the Mechanism of the Reverse Water–Gas Shift Reaction by Operando DRIFTS and Ultraviolet–Visible Spectroscopy
ACS Catalysis, 2018Co-Authors: L.f. Bobadilla, Jose Luis Santos, Svetlana Ivanova, José Antonio Odriozola, Atsushi UrakawaAbstract:The reaction mechanism of the reverse water–gas shift (RWGS) reaction was investigated using two commercial gold-based catalysts supported on Al2O3 and TiO2. The surface species formed during the reaction and reaction mechanisms were elucidated by transient and steady-state operando DRIFTS studies. It was revealed that RWGS reaction over Au/Al2O3 proceeds through the formation of formate intermediates that are reduced to CO. In the case of the Au/TiO2 catalyst, the reaction goes through a redox mechanism with the suggested formation of hydroxycarbonyl intermediates, which further decompose to CO and water. The Ti3+ species, the surface hydroxyls, and oxygen vacancies jointly participate. The absence of carbonyl species adsorbed on gold particles during the reaction for both catalysts indicates that the reaction pathway involving dissociative adsorption of CO2 on Au particles can be discarded. To complete the study, operando Ultraviolet–Visible Spectroscopy was successfully applied to confirm the presence ...
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unravelling the role of oxygen vacancies in the mechanism of the reverse water gas shift reaction by operando drifts and Ultraviolet Visible Spectroscopy
ACS Catalysis, 2018Co-Authors: L.f. Bobadilla, Jose Luis Santos, Svetlana Ivanova, José Antonio Odriozola, Atsushi UrakawaAbstract:The reaction mechanism of the reverse water–gas shift (RWGS) reaction was investigated using two commercial gold-based catalysts supported on Al2O3 and TiO2. The surface species formed during the reaction and reaction mechanisms were elucidated by transient and steady-state operando DRIFTS studies. It was revealed that RWGS reaction over Au/Al2O3 proceeds through the formation of formate intermediates that are reduced to CO. In the case of the Au/TiO2 catalyst, the reaction goes through a redox mechanism with the suggested formation of hydroxycarbonyl intermediates, which further decompose to CO and water. The Ti3+ species, the surface hydroxyls, and oxygen vacancies jointly participate. The absence of carbonyl species adsorbed on gold particles during the reaction for both catalysts indicates that the reaction pathway involving dissociative adsorption of CO2 on Au particles can be discarded. To complete the study, operando Ultraviolet–Visible Spectroscopy was successfully applied to confirm the presence ...
Andrew M. Beale - One of the best experts on this subject based on the ideXlab platform.
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Probing the influence of X-rays on aqueous copper solutions using time-resolved in situ combined video/X-ray absorption near-edge/Ultraviolet-Visible Spectroscopy.
The journal of physical chemistry. B, 2006Co-Authors: J. Gerbrand Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.
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probing the influence of x rays on aqueous copper solutions using time resolved in situ combined video x ray absorption near edge Ultraviolet Visible Spectroscopy
Journal of Physical Chemistry B, 2006Co-Authors: Gerbrand J Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.
Frank M. F. De Groot - One of the best experts on this subject based on the ideXlab platform.
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Probing the influence of X-rays on aqueous copper solutions using time-resolved in situ combined video/X-ray absorption near-edge/Ultraviolet-Visible Spectroscopy.
The journal of physical chemistry. B, 2006Co-Authors: J. Gerbrand Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.
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probing the influence of x rays on aqueous copper solutions using time resolved in situ combined video x ray absorption near edge Ultraviolet Visible Spectroscopy
Journal of Physical Chemistry B, 2006Co-Authors: Gerbrand J Mesu, Andrew M. Beale, Frank M. F. De Groot, Bert M. WeckhuysenAbstract:Time-resolved in situ video monitoring and Ultraviolet-Visible Spectroscopy in combination with X-ray absorption near-edge Spectroscopy (XANES) have been used for the first time in a combined manner to study the effect of synchrotron radiation on a series of homogeneous aqueous copper solutions in a microreactor. This series included both non biologically relevant (pyridine, bipyridine, neocuproine, terpyridine, dimethylpyridine, ammonia, ethylenediamine, and 1,10-phenanthroline) and biologically relevant (histidine, glycine, and imidazole) ligands. It was found that when water is present as solvent, gas bubbles are formed under the influence of the X-ray beam. At the liquid-gas interface of these bubbles, in particular cases colloidal copper nanoparticles are formed. This reduction process was found to be influenced by the type of copper precursor salt (SO(4)(2-), NO(3)(-), and Cl(-)), the ligands surrounding the copper cation, and the redox potential of the copper complexes (ranging between +594 and -360 mV). In other words, in some cases, no reduction was encountered (e.g., ammonia in the presence of SO(4)(2-) and NO(3)(-)), whereas in other cases reduction to either Cu(+) (neocuproine with SO(4)(2-)) or Cu(0) (e.g., histidine and imidazole both with SO(4)(2-), NO(3)(-), and Cl(-)) was observed. These results illustrate the added value of video Spectroscopy for the interpretation of in situ XANES studies. Not only do the results give an illustration of the parameters that are important in the redox processes that occur in biological systems, they also show the potential problems associated with studying catalytic processes in aqueous solutions by XANES Spectroscopy.