Transformation products of two-line ferrihydrite associated with Lu(III) were studied after 12 years of aging using aberration-corrected high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM), high-efficiency energy-dispersive X-ray spectroscopy (EDXS), and density functional theory (DFT). The transformation products consisted of hematite nanoparticles with overgrown goethite needles. High-efficiency STEM-EDXS revealed that Lu is only associated with goethite needles, and atomic-resolution HAADF-STEM reveals structural incorporation of Lu within goethite, partially replacing structural Fe sites. This finding corroborates those recently obtained by AsFlFFF and EXAFS spectroscopy on the same sample (Finck et al. 2018). DFT calculations indicate that Lu incorporation within goethite or hematite are almost equally likely, suggesting that experimental parameters such as temperature and reaction time which affect reaction kinetics, play important roles in determining the Lu uptake. It seems likely that these results may be transferable to predict the behavior of chemically homologous trivalent actinides.
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http://dx.doi.org/10.1007/s11356-018-1904-7 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India.
Heterogeneous catalysts have emerged as a potential key for closing the carbon cycle by converting carbon dioxide (CO) into value-added chemicals. In this work, we report a highly active and stable ceria (CeO)-based electronically tuned trimetallic catalyst for CO to CO conversion. A unique distribution of electron density between the defective ceria support and the trimetallic nanoparticles (of Ni, Cu, Zn) was established by creating the strong metal support interaction (SMSI) between them.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Dipartimento di Scienze Fisiche e Chimiche, Universita degli Studi dellAquila, Coppito, 67100 L'Aquila, Italy.
We present a comprehensive theoretical study, using state-of-the-art density functional theory simulations, of the structural and electrochemical properties of amorphous pristine and iron-doped nickel-(oxy)hydroxide catalyst films for water oxidation in alkaline solutions, referred to as NiCat and Fe:NiCat. Our simulations accurately capture the structural changes in locally ordered units, as reported by X-ray absorption spectroscopy, when the catalyst films are activated by exposure to a positive potential. We emphasize the critical role of proton-coupled electron transfer in the reversible oxidation of Ni(II) to Ni(III/IV) during this activation.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Materials Science and Engineering, Incheon National University, Incheon 22012, Korea.
HfO-based thin films have garnered significant interest for integrating robust ferroelectricity into next-generation memory and logic chips, owing to their applicability with modern Si device technology. While numerous studies have focused on enhancing ferroelectric properties and understanding their fundamentals, the fabrication of ultrathin HfO-based ferroelectric films has seldom been reported. This study presents the concept of atomic-level stoichiometry control of ferroelectric HfZrO films by examining the molecular-level interactions of precursor molecules in the atomic layer deposition (ALD) process through theoretical calculations.
View Article and Find Full Text PDFJ Fluoresc
January 2025
School of Chemistry & Environmental Engineering, Jilin Provincial International Joint Research Center of Photo-Functional Materials and Chemistry, Changchun University of Science and Technology, Changchun, 130022, China.
In this work, a new fluorescent sensor for detecting Cu was developed based on the Rhodamine derivative. It displayed strong fluorescence enhancement upon the addition of Cu, and other common metal ions do not significantly affect the optical properties of the sensor. This optical signal change caused solely by Cu is due to the opening of the lactone amide spiro ring structure, resulting in fluorescence emission.
View Article and Find Full Text PDFMikrochim Acta
January 2025
Key Laboratory of Eco-Functional Polymer Materials of the Ministry of Education, Key Laboratory of Polymer Materials of Gansu Province, College of Chemistry and Chemical Engineering, Northwest Normal University, Lanzhou, 730070, Gansu, China.
A pentafluoropropionic acid-functionalized fluorescent metal-organic framework material (UiO-66-NH-PFPA) is prepared by a simple post-synthetic modification (PSM) strategy for the sensitive and selective detection of dichloran (DCN). The results of fluorescence experiments demonstrate that the sensitivity of UiO-66-NH-PFPA (limit of detection, LOD = 0.478 μM) to DCN is nearly 10.
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