Superparamagnetic relaxation times for mixed anisotropy and high energy barriers with intermediate to high damping: 2. Uniaxial axis in a 〈111〉 direction

2006 ◽  
Vol 7 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Andrew J. Newell
Keyword(s):  
Relaxation Times ◽  
High Energy ◽  
Energy Barriers ◽  
Superparamagnetic Relaxation

Planar Dy3 + Dy3 clusters: design, structure and axial ligand perturbed magnetic dynamics

2015 ◽  
Vol 44 (47) ◽  
pp. 20316-20320 ◽  
Author(s):  
Xiao-Lei Li ◽  
Han Li ◽  
Di-Ming Chen ◽  
Chao Wang ◽  
Jianfeng Wu ◽  
...  
Keyword(s):  
Single Molecule ◽  
High Energy ◽  
Axial Ligand ◽  
Magnetic Behaviour ◽  
Energy Barriers ◽  
Magnetic Dynamics ◽  
Design Structure

Coupling Dy3 triangles results in two unique Dy6 complexes showing single-molecule magnetic behaviour with high energy barriers of 116 and 181 K for Dy6–NO3 and Dy6–SCN, respectively.

scholarly journals Shifted loops and coercivity from field-imprinted high-energy barriers in ferritin and ferrihydrite nanoparticles

2011 ◽  
Vol 84 (10) ◽  
Author(s):  
N. J. O. Silva ◽  
V. S. Amaral ◽  
A. Urtizberea ◽  
R. Bustamante ◽  
A. Millán ◽  
...  
Keyword(s):  
High Energy ◽  
Energy Barriers

N.M.R. studies of some chromium(III) dithiocarbamate complexes

1974 ◽  
Vol 27 (10) ◽  
pp. 2089 ◽  
Author(s):  
RM Golding ◽  
PC Healy ◽  
P Colombera ◽  
AH White
Keyword(s):  
Temperature Dependence ◽  
Hyperfine Coupling ◽  
Relaxation Mechanism ◽  
High Energy ◽  
Coupling Constants ◽  
Energy Barriers ◽  
Double Peak ◽  
Hyperfine Coupling Constants

The temperature dependence of the proton N.M.R. spectra of some simple tris(N,N-disubstituted dithiocarbamato)chromium(111) derivatives, [Cr(S2CNR2)3], has been studied in deuterochloroform solution over the range ? 60� to + 60�C. In these spectra, which are very broad, the N-CHn protons in certain cases exhibit a double peak unlike the iron(111) or manganese(111) complexes-probably a consequence of high energy barriers between the Δ and Δ enantiomers, the broadness of the spectra being ascribed to the lack of an appropriate relaxation mechanism. The spectra of a number of further iron(111) and manganese(111) derivatives are reported and the hyperfine coupling constants in the three series of complexes compared.

scholarly journals Interrogation of the Selectivity and Electrokinetics of CO2 Reduction by AgSn Films in the Presence of Protic Organic [DBU–H]+ Cations as judged by Impedance Spectroscopy and Distribution of Relaxation Times Analysis

2021 ◽  
Author(s):  
Thabiso Kunene ◽  
Abderrahman Atifi ◽  
Joel Rosenthal
Keyword(s):  
Impedance Spectroscopy ◽  
Composite Film ◽  
Electrochemical Impedance ◽  
Relaxation Times ◽  
Composite Films ◽  
Co2 Reduction ◽  
Electrolyte Solutions ◽  
High Energy ◽  
Porous Films ◽  
Fast Kinetics

The use of renewable electricity to synthesize high energy and high value chemicals via reduction of CO2 is an attractive strategy for renewable energy storage. Improving our understanding of how heterogeneous CO2 reduction electrocatalysts function is important to designing efficient systems for conversion of CO2 into commodity chemicals such as CO and HCO2H. Both Ag- and Sn-based materials have been previously considered as CO2 reduction catalysts and offer distinct CO2RR selectivities. In this work, we have considered electrodeposited composite film electrodes prepared from electroplating baths with varying ratios of Ag+ and Sn2+ triflates to understand how the performance of such composite materials varies as a function of composition. XPS analysis confirms that for each composite film electrodes, Ag existed in the metallic (Ag0) state, while the Sn was mainly oxidized (Sn2+/4+). The AgSn composite film electrodes studied herein are therefore best considered as AgSnOx cathodes with varying ratios of Ag0:Sn2+/4+. These systems were assessed as CO2RR electrocatalysts and were found to promote the 2e–/2H+ reductions to deliver CO and HCOOH with fast kinetics and high efficiencies from electrolyte solutions containing the protic organic cation [DBU–H]+. While Sn-rich composite films showed poor selectivities for CO versus HCO2H, a significant increase in CO versus HCO2H selectivity (up to 99%) is achieved for composite film electrodes in which the Ag content ranged from 25 - 75%. By tuning the ratio of Ag0 to SnOx we prepared composite film cathode materials that support quantitative current efficiencies for generation of CO with geometric current densities approaching 30 mA/cm2 at applied overpotentials that are less than 750 mV were realized. Additionally, electrochemical impedance spectroscopy (EIS) coupled with analysis of the distribution of relaxation times (DRT) was used to better understand factors important to the composites’ activity under CO2RR conditions. Probing the dynamics with DRT analysis revealed that multiple processes relating to both adsorption and diffusion-controlled events are important to the activity of the electrocatalysts considered in this work. The collection of electroanalytical investigations suggest that synergistic interactions between Ag and SnOx give rise to porous films that support enhanced CO2RR kinetics and that mixing of Ag with SnOx enhances the efficacy of adsorption and stabilization of reduced CO2 intermediates and [DBU–H]+ cations to facilitate CO evolution at the cathode/electrolyte interface.

Sign in / Sign up

Export Citation Format

Share Document