scholarly journals Redox Activity of Pyridine-Oxazoline Ligands in the Stabilization of Low-Valent Organonickel Radical Complexes

2021 ◽  
Author(s):  
Clifton L. Wagner ◽  
Gabriel Herrera ◽  
Qiao Lin ◽  
Chunhua T. Hu ◽  
Tianning Diao
Keyword(s):  
Redox Activity ◽  
Low Valent ◽  
Oxazoline Ligands

Tuning the Redox Activity of Metal−Organic Frameworks for Enhanced, Selective O2 Binding

2019 ◽  
Author(s):  
Andrew Rosen ◽  
M. Rasel Mian ◽  
Timur Islamoglu ◽  
Haoyuan Chen ◽  
Omar Farha ◽  
...  
Keyword(s):  
Density Functional ◽  
Metal Organic Frameworks ◽  
Redox Activity ◽  
Screening Methods ◽  
Bridging Ligands ◽  
Metal Centers ◽  
Computational Screening ◽  
Open Metal Sites ◽  
Metal Organic ◽  
Unsaturated Metal Sites

<p>Metal−organic frameworks (MOFs) with coordinatively unsaturated metal sites are appealing as adsorbent materials due to their tunable functionality and ability to selectively bind small molecules. Through the use of computational screening methods based on periodic density functional theory, we investigate O<sub>2</sub> and N<sub>2</sub> adsorption at the coordinatively unsaturated metal sites of several MOF families. A variety of design handles are identified that can be used to modify the redox activity of the metal centers, including changing the functionalization of the linkers (replacing oxido donors with sulfido donors), anion exchange of bridging ligands (considering μ-Br<sup>-</sup>, μ-Cl<sup>-</sup>, μ-F<sup>-</sup>, μ-SH<sup>-</sup>, or μ-OH<sup>-</sup> groups), and altering the formal oxidation state of the metal. As a result, we show that it is possible to tune the O<sub>2</sub> affinity at the open metal sites of MOFs for applications involving the strong and/or selective binding of O<sub>2</sub>. In contrast with O<sub>2</sub> adsorption, N<sub>2</sub> adsorption at open metal sites is predicted to be relatively weak across the MOF dataset, with the exception of MOFs containing synthetically elusive V<sup>2+</sup> open metal sites. As one example from the screening study, we predict that exchanging the μ-Cl<sup>-</sup> ligands of M<sub>2</sub>Cl<sub>2</sub>(BBTA) (H<sub>2</sub>BBTA = 1<i>H</i>,5<i>H</i>-benzo(1,2-d:4,5-d′)bistriazole) with μ-OH<sup>-</sup> groups would significantly enhance the strength of O<sub>2</sub> adsorption at the open metal sites without a corresponding increase in the N<sub>2</sub> affinity. Experimental investigation of Co<sub>2</sub>Cl<sub>2</sub>(BBTA) and Co<sub>2</sub>(OH)<sub>2</sub>(BBTA) confirms that the former exhibits only weak physisorption, whereas the latter is capable of chemisorbing O<sub>2</sub> at room temperature. The chemisorption behavior is attributed to the greater electron-donating character of the μ-OH<sup>-</sup><sub> </sub>ligands and the presence of H-bonding interactions between the μ-OH<sup>-</sup> bridging ligands and the O<sub>2</sub> adsorbate.</p>

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Experimental Assessment of the Practical Oxidative Stability of Lithium Thiophosphate Solid Electrolytes

2019 ◽  
Author(s):  
Georg Dewald ◽  
Saneyuki Ohno ◽  
Marvin Kraft ◽  
Raimund Koerver ◽  
Paul Till ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Solid State ◽  
Oxidative Stability ◽  
Photoelectron Spectroscopy ◽  
Solid Electrolytes ◽  
Stability Limit ◽  
Lithium Ion ◽  
High Energy ◽  
Redox Activity ◽  
Solid State Batteries

<p>All-solid-state batteries are often expected to replace conventional lithium-ion batteries in the future. However, the practical electrochemical and cycling stability of the best-conducting solid electrolytes, i.e. lithium thiophosphates, are still critical issues that prevent long-term stable high-energy cells. In this study, we use <i>stepwise</i><i>cyclic voltammetry </i>to obtain information on the practical oxidative stability limit of Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>, a Li<sub>2</sub>S‑P<sub>2</sub>S<sub>5</sub>glass, as well as the argyrodite Li<sub>6</sub>PS<sub>5</sub>Cl solid electrolytes. We employ indium metal and carbon black as the counter and working electrode, respectively, the latter to increase the interfacial contact area to the electrolyte as compared to the commonly used planar steel electrodes. Using a stepwise increase in the reversal potentials, the onset potential at 25 °C of oxidative decomposition at the electrode-electrolyte interface is identified. X‑ray photoelectron spectroscopy is used to investigate the oxidation of sulfur(-II) in the thiophosphate polyanions to sulfur(0) as the dominant redox process in all electrolytes tested. Our results suggest that after the formation of these decomposition products, significant redox behavior is observed. This explains previously reported redox activity of thiophosphate solid electrolytes, which contributes to the overall cell performance in solid-state batteries. The <i>stepwise cyclic voltammetry</i>approach presented here shows that the practical oxidative stability at 25 °C of thiophosphate solid electrolytes against carbon is kinetically higher than predicted by thermodynamic calculations. The method serves as an efficient guideline for the determination of practical, kinetic stability limits of solid electrolytes. </p>

Adsorption and advanced oxidation of diverse pharmaceuticals and personal care products (PPCPs) from water using highly efficient rGO–nZVI nanohybrids

2020 ◽  
Vol 6 (8) ◽  
pp. 2223-2238 ◽  
Author(s):  
Arvid Masud ◽  
Nita G. Chavez Soria ◽  
Diana S. Aga ◽  
Nirupam Aich
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Personal Care Products ◽  
Advanced Oxidation ◽  
Zero Valent Iron ◽  
Redox Activity ◽  
Personal Care ◽  
Adsorption Sites ◽  
Reduced Graphene ◽  
Nanoscale Zero Valent Iron

Reduced graphene oxide-nanoscale zero valent iron (rGO–nZVI) nanohybrid, with tunable adsorption sites of rGO and unique catalytic redox activity of nZVI, perform enhanced removal of diverse PPCPs from water.

A New Approach to Stable Cationic and Anionic Redox Activity in O3‐Layered Cathode for Sodium‐Ion Batteries

2021 ◽  
pp. 2100901
Author(s):  
Natalia Voronina ◽  
Najma Yaqoob ◽  
Hee Jae Kim ◽  
Kug‐Seung Lee ◽  
Hee‐Dae Lim ◽  
...  
Keyword(s):  
Sodium Ion ◽  
Redox Activity ◽  
Sodium Ion Batteries ◽  
New Approach

Tunable Redox Activity at Fe3+ Centers in Colloidal ATiO3 (A = Sr and Ba) Nanocrystals

2021 ◽  
Author(s):  
Muhammad Abdullah ◽  
Ruby J. Nelson ◽  
Kevin R. Kittilstved
Keyword(s):  
Redox Activity
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