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1.
JACS Au ; 1(5): 527-535, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34467315

RESUMO

The growing societal and political focus on the use of environmentally friendly technologies has led to an ever-increasing interest in electrolysis technologies in the scientific communities. This development is reflected by the plethora of candidate catalysts for the hydrogen and oxygen evolution reactions, as well as the CO2 reduction reaction, reported in the literature. However, almost none of them entered the stage of application yet. Likewise, the reports on process engineering inadequately address the utilization of these catalysts, as well as electrode and cell concepts, that might be suitable for the market. Evidently, a closer collaboration between chemists and engineers from industry and academia is desirable to speed up the development of these disruptive technologies. Herein, we elucidate the critical parameters and highlight the necessary aspects to accelerate the development of industrially relevant catalysts capable of fulfilling the forthcoming challenges related to energy conversion and storage. The aim of this Perspective, composed by industrial and academic partners, is to critically question current undertakings and to encourage researchers to strike interdisciplinary research pathways.

2.
Environ Sci Technol ; 49(7): 4559-66, 2015 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-25747941

RESUMO

Phosphate (Pi) sequestration by a lanthanum (La) exchanged clay mineral (La-Bentonite), which is extensively used in chemical lake restoration, was investigated on the molecular level using a combination of (31)P and (139)La solid state NMR spectroscopy (SSNMR), extended X-ray absorption spectroscopy (EXAFS), powder X-ray diffraction (PXRD) and sorption studies. (31)P SSNMR show that all Pi was immobilized as rhabdophane (LaPO4·n H2O, n ≤ 3), which was further supported by (139)La SSNMR and EXAFS. However, PXRD results were ambiguous with respect to rhabdophane and monazite (LaPO4). Adsorption studies showed that at dissolved organic carbon (DOC) concentration above ca. 250 µM the binding capacity was only 50% of the theoretical value or even less. No other La or Pi phases were detected by SSNMR and EXAFS indicating the effect of DOC is kinetic. Moreover, (31)P SSNMR showed that rhabdophane formed upon Pi sequestration is in close proximity to the clay matrix.


Assuntos
Silicatos de Alumínio/química , Bentonita/química , Recuperação e Remediação Ambiental , Eutrofização , Lantânio/química , Fosfatos/química , Adsorção , Argila , Lagos/química , Espectroscopia de Ressonância Magnética , Espectroscopia por Absorção de Raios X , Difração de Raios X
3.
Acta Crystallogr C ; 69(Pt 2): 105-10, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23377672

RESUMO

The title compound, with nominal formula Cu(2)ScZr(PO(4))(3), has a beige coloration and displays fast Cu(+) cation conduction at elevated temperatures. It adopts a NASICON-type structure in the space group R3c. The examined crystal was an obverse-reverse twin with approximately equal twin components. The [Sc(III)Zr(IV)(PO(4))(3)](2-) framework is composed of corner-sharing Sc/ZrO(6) octahedra and PO(4) tetrahedra. The Sc and Zr atoms are disordered on one atomic site on a crystallographic threefold axis. The P atom of the phosphate group lies on a crystallographic twofold axis. Nonframework Cu(+) cations occupy three positions. Two of the Cu(+) positions generate an approximately circular distribution around a site of 3 symmetry, referred to as the M1 site in the NASICON-type structure. The other Cu(+) position is situated close to the twofold symmetric M2 site, displaced into a position with a distorted square-based pyramidal coordination geometry. The structure has been determined at 100, 200 and 300 K. Changes in the refined site-occupancy factors of the Cu(+) positions suggest increased mobility of Cu(+) around the circular orbit close to the M1 site at room temperature, but no movement into or out of the M2 site. Free refinement of the Cu site-occupancy factors suggests that the formula of the crystal is Cu(1.92(1))ScZr(PO(4))(3), which is consistent with the low-level presence of Cu(2+) exclusively in the M2 site.

4.
Acta Crystallogr C ; 67(Pt 3): i21-3, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21368400

RESUMO

The title compound, Cu(0.5)Mn(2.5)(PO(4))(2), is a copper-manganese phosphate solid solution with the graftonite-type structure, viz. (Mn,Fe,Ca,Mg)(3)(PO(4))(2). The structure has three distinct metal cation sites, two of which are occupied by Mn(II) and one of which accommodates Cu(II). Incorporation of Cu(II) into the structure distorts the coordination geometry of the metal cation site from five-coordinate square-pyramidal towards four-coordinate flattened tetrahedral, and serves to contract the structure principally along the c axis.

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