Stereochemical and conformational control of metal redox processes: the co-ordination chemistry of the mixed N- and S-donor macrocyclic crowns [18]aneN2S4and Me2[18]aneN2S4

1990 ◽  
Vol 19 (3) ◽  
pp. 239-269 ◽  
Author(s):  
Gillian Reid ◽  
Martin Schröder
Keyword(s):  
Redox Processes ◽  
Conformational Control ◽  
Metal Redox

Metal Redox Processes for the Controlled Synthesis of Metal Alloy Nanoparticles

2015 ◽  
Vol 54 (14) ◽  
pp. 4203-4207 ◽  
Author(s):  
Alec Kirkeminde ◽  
Stan Spurlin ◽  
Laura Draxler-Sixta ◽  
Jamie Cooper ◽  
Shenqiang Ren
Keyword(s):  
Metal Alloy ◽  
Controlled Synthesis ◽  
Alloy Nanoparticles ◽  
Redox Processes ◽  
Metal Redox

Metal Redox Processes for the Controlled Synthesis of Metal Alloy Nanoparticles

2015 ◽  
Vol 127 (14) ◽  
pp. 4277-4281 ◽  
Author(s):  
Alec Kirkeminde ◽  
Stan Spurlin ◽  
Laura Draxler-Sixta ◽  
Jamie Cooper ◽  
Shenqiang Ren
Keyword(s):  
Metal Alloy ◽  
Controlled Synthesis ◽  
Alloy Nanoparticles ◽  
Redox Processes ◽  
Metal Redox

Probing electrochemical and electrocatalytic properties of cobalt(II) and manganese(III) octakis(hexylthio)phthalocyanine as self-assembled monolayers

2010 ◽  
Vol 14 (11) ◽  
pp. 932-947 ◽  
Author(s):  
Philani Mashazi ◽  
Edith Antunes ◽  
Tebello Nyokong
Keyword(s):  
Modified Electrodes ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Gold Electrodes ◽  
Redox Processes ◽  
Electrocatalytic Reduction ◽  
Metal Centers ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Metal Redox

New peripherally (β) and non-peripherally (α) substituted metal octakis(hexylthio)phthalocyanines (β- and α-MOcHexTPc) containing cobalt and manganese as metal centers were synthesized. Their characterization using electrochemical methods showed that these complexes exhibit several redox processes at E1/2 (mV vs. Ag∣AgCl) = 380 (212) (I), 1140 (864) (II), -450 (-460) (III) and -1170 (-1304) (IV) for β- (α-) CoOcHexTPc . These redox processes were assigned to CoIIIPc-2/CoIIPc-2 (I) , CoIIIPc-1/CoIIIPc-2 (II) , CoIIPc-2/CoIPc-2 (III) and CoIPc-2/CoIPc-3 (IV) using spectroelectrochemistry. For the β- (α-) MnOcHexTPc complex the redox processes were observed at E1/2 (mV vs. Ag∣AgCl) = -20 (5) (I), -530 (-640) (II) and -1270 (-1380) (III) and were assigned to MnIIIPc-2/MnIIPc-2 (I), MnIIPc-2/MnIIPc-3 (II) and MnIIPc-3/MnIIPc-4 (III) . Electrochemical and microscopic characterization using AFM showed that the self-assembled monolayers (SAMs) are formed on the gold surface using these complexes. The electrochemical characterization showed the blocking of the Faradaic processes at SAMs modified electrodes and these reactions are well-known to easily occur at unmodified gold electrodes. The AFM characterization showed an increase in surface roughness upon modifying the gold surface with MOcHexTPc SAMs, further confirming the presence of the monolayers on the gold surface. The MOcHexTPc SAMs were investigated for their electrocatalytic application towards H2O2 detection. The MOcHexTPc SAMs modified gold electrodes gave excellent currents for H2O2 detection. The observed H 2 O2 electrocatalytic reduction peaks were close to where the metal redox processes from the MOcHexTPc occurred, showing the involvement of the metal redox processes in the electrocatalytic mediation reactions.

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

Anionic and Cationic Redox Processes in β-Li2IrO3 and Their Structural Implications on Electrochemical Cycling in Li-Ion Cell

2019 ◽  
Author(s):  
Paul Pearce ◽  
Gaurav Assat ◽  
Antonella Iadecola ◽  
François Fauth ◽  
Rémi Dedryvère ◽  
...  
Keyword(s):  
Analytical Techniques ◽  
Charge Compensation ◽  
Coupling Mechanism ◽  
Redox Processes ◽  
Positive Electrodes ◽  
X Ray ◽  
Electrochemical Cycling ◽  
Li Ion ◽  
Electrochemical Instability ◽  
High Degree

The recent discovery of anionic redox as a means to increase the energy density of transition metal oxide positive electrodes is now a well established approach in the Li-ion battery field. However, the science behind this new phenomenon pertaining to various Li-rich materials is still debated. Thus, it is of paramount importance to develop a robust set of analytical techniques to address this issue. Herein, we use a suite of synchrotron-based X-ray spectroscopies as well as diffraction techniques to thoroughly characterize the different redox processes taking place in a model Li-rich compound, the tridimentional hyperhoneycomb β-Li2IrO3. We clearly establish that the reversible removal of Li+ from this compound is associated to a previously described reductive coupling mechanism and the formation of the M-(O-O) and M-(O-O)* states. We further show that the respective contributions to these states determine the spectroscopic response for both Ir L3-edge X-ray absorption spectroscopy (XAS) and X-ray photoemissions spectroscopy (XPS). Although the high covalency and the robust tridimentional structure of this compound enable a high degree of reversibile delithiation, we found that pushing the limits of this charge compensation mechanism has significant effects on the local as well as average structure, leading to electrochemical instability over cycling and voltage decay. Overall, this work highlights the practical limits to which anionic redox can be exploited and sheds some light on the nature of the oxidized species formed in certain lithium-rich compounds.<br>

An Excel Workbook for Identifying Redox Processes in Ground Water

2009 ◽  
Author(s):  
Bryant C. Jurgens ◽  
Peter B. McMahon ◽  
Francis H. Chapelle ◽  
Sandra M. Eberts
Keyword(s):  
Ground Water ◽  
Redox Processes
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