XAS studies on Cu(II) complexes with derivatives of phenoxyacetic and benzoic acids

Klepka, Marcin T.; Drzewiecka, Aleksandra; Wolska, A.; Ferenc, W.

doi:10.1016/j.cplett.2012.10.008

Cited by 15 publications

(5 citation statements)

References 18 publications

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“…40 Therefore, Cu K-edge XANES spectra were measured in order to corroborate the oxidation states of Cu deduced from XPS. It has been found that the energy position of the rising edge of the spectra and shape of the white line for all the TiO 2 −P25 modified with copper (Cu alone or associated with Ag) are characteristic of Cu II species, 41 as shown in Figure 4.…”

Section: Resultsmentioning

confidence: 93%

Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

et al. 2016

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Ag and CuO nanoparticles (NPs) synthesized on the surface of commercial TiO 2 (P25) by radiolytic reduction were characterized by diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), energydispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). In the case of modification with silver and copper, results from HAADF-STEM, EDS, XPS, and XAS show that Ag@CuO nanoparticles (large silver cores decorated with small clusters of CuO) were obtained on TiO 2 −P25. The photocatalytic properties of bare and modified TiO 2 −P25 were studied for phenol photodegradation and for acetic acid oxidation under UV and visible irradiation. The mechanisms involved in photocatalysis were studied by time-resolved microwave conductivity (TRMC) and action spectra (AS). The electronic properties of the surface-modified TiO 2 −P25 were studied by TRMC to follow the charge-carrier dynamics. The modification with Ag nanoparticles or CuO nanoclusters induces an increase in the photocatalytic activity under both UV and visible light. The photocatalytic activity of Ag@CuO/P25 is higher under UV light but lower under visible light compared to the activity of CuO/P25 and Ag/P25. TRMC measurements show that surface modification of TiO 2 −P25 with Ag, CuO, and Ag@CuO nanoparticles plays a role in charge-carrier separation, increasing the activity under UV-light, and that Ag@CuO NPs are more efficient electron scavengers than Ag NPs and CuO nanoclusters. The localized surface plasmon resonance (LSPR) of Ag NPs and the narrow band gap of CuO induce an activity under visible light. The TRMC shows also responses under visible-light irradiation at different fixed wavelengths indicating that electrons are injected from Ag NPs in the conduction band (CB) of TiO 2 −P25. Moreover, under visible light, the photocatalytic activity of CuO/P25 is higher than that of plasmonic Ag/P25. CuO is able to activate TiO 2 −P25 in a wider range of wavelengths under visible-light irradiation, compared to the activation achieved by the presence of silver. The action spectra correlate with the absorption spectra for irradiation wavelengths in the range of 350−470 nm proving that decomposition of acetic acid is carried out by a photocatalytic mechanism.

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Section: Resultsmentioning

confidence: 93%

Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

et al. 2016

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“…While for glyphosate this complexation effect is counterbalanced by strong ternary inner-sphere surface complex formation 23 , this is obviously not the case for MCPA. No ternary Cu–MCPA inner-sphere surface complex formation has been found by EXAFS analysis (data not shown), likely because of no free functional groups left over as in case of glyphosate 24 . In presence of MCPA, only weak outer-sphere ternary surface complex formation occurred of the anionic Cu-MCPA moeity, contributing about 10% of the adsorbed Cu at pH 5.4 (brown curve in Fig.…”

Section: Resultsmentioning

confidence: 94%

Time-lapse 3D imaging by positron emission tomography of Cu mobilized in a soil column by the herbicide MCPA

Kulenkampff

Stoll

Gründig

et al. 2018

Sci Rep

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Phenoxyalkanoic acids like the 4-chloro-2-methylphenoxyacetic acid (MCPA) are the second highest used xenobiotic herbicides worldwide after glyphosate because of their apparently favorable environmental properties. Experimental batch equilibration data suggested a reduced Cu adsorption efficiency with the soil mineral goethite below pH 6 in presence of MCPA. This has been verified by advanced surface complexation adsorption modelling involving dissolved Cu-MCPA complexation constants. Positron emission tomography is a non-invasive molecular imaging method for time-resolved three-dimensional information commonly applied on non-retarded tracers in soil core scale experiments. Mineral surface reactive tracers like Cu-64 are too immobile for the relatively short observation times available with this advanced imaging technique. However, Cu-64 radiolabeled Cu-MCPA complex migration could be observed in as long as 10-cm artificial soil test columns where break-through occurred within a few days. For the first time, time-lapse movies of Cu migration in the opaque soil columns were recorded using this novel reactive transport process tomography approach.

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“…The great advantage of XAS is that it can be used for crystal as well as amorphous materials at different states: solid, liquid or gaseous. XAS provides information about the local atomic order, coordination number, kind of atoms, oxidation state, relative disorder and even angles between central atom and near neighbours [8][9][10]. Data obtained from XAS combined with the density functional theory (DFT) calculations allowed building models of the complexes.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, structural studies and biological activity of new Cu(II) complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin

Klepka

Drzewiecka-Antonik

Wolska

et al. 2015

Journal of Inorganic Biochemistry

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XAS studies on Cu(II) complexes with derivatives of phenoxyacetic and benzoic acids

Cited by 15 publications

References 18 publications

Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

Time-lapse 3D imaging by positron emission tomography of Cu mobilized in a soil column by the herbicide MCPA

Synthesis, structural studies and biological activity of new Cu(II) complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin

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XAS studies on Cu(II) complexes with derivatives of phenoxyacetic and benzoic acids

Cited by 15 publications

References 18 publications

Surface Modification of TiO2 with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

Surface Modification of TiO2 with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

Time-lapse 3D imaging by positron emission tomography of Cu mobilized in a soil column by the herbicide MCPA

Synthesis, structural studies and biological activity of new Cu(II) complexes with acetyl derivatives of 7-hydroxy-4-methylcoumarin

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Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis

Surface Modification of TiO₂ with Ag Nanoparticles and CuO Nanoclusters for Application in Photocatalysis