Activation of CO2 on Copper Surfaces: The Synergy Between Electric Field, Surface Morphology and Excess Electrons

Author(s):  
Amin Jafarzadeh ◽  
Kristof M. Bal ◽  
Annemie Bogaerts ◽  
Erik C. Neyts

<p>In this work we use DFT calculations to study the combined effect of external electric fields, surface morphology and surface charge on CO<sub>2</sub> activation over Cu (111), Cu (211), Cu (110) and Cu (001) surfaces. We observe that the binding energy of the CO<sub>2</sub> molecule on Cu surfaces rises significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field towards facilitating the formation of a carbonate-like CO<sub>2</sub> structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently gives rise to an improved bending of the CO<sub>2</sub> molecule and C-O bond length elongation. On the other hand, a net charge in the absence of externally applied electric field shows only a marginal effect on CO<sub>2</sub> binding. The chemisorbed CO<sub>2</sub> is more stable and further activated when the effects of an external electric field, rough surface and surface charge are combined. These results can help to elucidate the underlying factors that control CO<sub>2</sub> activation in heterogeneous and plasma catalysis, as well as in electrochemical processes.</p>

2020 ◽  
Author(s):  
Amin Jafarzadeh ◽  
Kristof M. Bal ◽  
Annemie Bogaerts ◽  
Erik C. Neyts

<p>In this work we use DFT calculations to study the combined effect of external electric fields, surface morphology and surface charge on CO<sub>2</sub> activation over Cu (111), Cu (211), Cu (110) and Cu (001) surfaces. We observe that the binding energy of the CO<sub>2</sub> molecule on Cu surfaces rises significantly upon increasing the applied electric field strength. In addition, rougher surfaces respond more effectively to the presence of the external electric field towards facilitating the formation of a carbonate-like CO<sub>2</sub> structure and the transformation of the most stable adsorption mode from physisorption to chemisorption. The presence of surface charges further strengthens the electric field effect and consequently gives rise to an improved bending of the CO<sub>2</sub> molecule and C-O bond length elongation. On the other hand, a net charge in the absence of externally applied electric field shows only a marginal effect on CO<sub>2</sub> binding. The chemisorbed CO<sub>2</sub> is more stable and further activated when the effects of an external electric field, rough surface and surface charge are combined. These results can help to elucidate the underlying factors that control CO<sub>2</sub> activation in heterogeneous and plasma catalysis, as well as in electrochemical processes.</p>


1998 ◽  
Vol 53 (1-2) ◽  
pp. 17-26
Author(s):  
Mohamed Fahmy El-Sayed

Abstract A linear stability analysis of a novel electrohydrodynamic Kelvin-Helmholtz system consisting of the superposition of two uniformly rotating dielectric media is presented. The characteristic equation for such an arrangement is derived, which in turn yields a stability criterion for velocity differences of disturbances at a given rotation frequency. The conditions of stability for long and short wave perturbations are obtained, and their dependence on rotation, surface tension and applied electric field is discussed. Limiting cases for vanishing fluid velocities, rotation frequency, and applied electric field are also discussed. Under suitable limits, results of previous works are recovered. A detailed analysis for tangential and normal applied electric fields, in the presence and absence of surface charges, is carried out.


2013 ◽  
Vol 743-744 ◽  
pp. 126-137 ◽  
Author(s):  
Jian Ping Yang ◽  
Jing Kuan Duan ◽  
Chang Xiu Fan ◽  
Pei De Han ◽  
Shuang Xi Shao ◽  
...  

In this investigation, the multi-walled carbon nanotubes (MWCNTs) were dispersed in an interpenetrating polymer networks (IPNs) based on acrylate and cycloaliphatic epoxy resin (CER). The influences of the external electric field on the MWCNTs dispersion and the microstructure of host matrix were evaluated by means of optical microscopy, scanning electric microscopy (SEM) and atomic force microscopy (AFM), respectively. The microscopy measurements showed that the distribution of the MWCNTs depended strongly on the properties of the applied electric field. Applying AC electric field to the liquid MWCNTs/thermoset systems during curing stage could redistribute the MWCNTs, which arranged them in chain-like structures and oriented fibrous inclusions parallel to the applied electric field. However, the similar phenomenon was not observed in DC electric field. From the observations of AFM measurement, it was found that the utilization of the external electric field resulted in the nanostructured twophase structures in the resulting MWCNTs/thermoset nanocomposites. These novel electric-field-induced morphology transformations were mainly attributed to the curing process under the applied electric fields. The relationships between the microstructures and various physical properties of nanocomposites were also presented in this paper. The resulting nanocomposites displayed the interesting dielectric properties and the thermal stability properties, which significantly depended on their special microstructures of inclusions and the host matrix.


Author(s):  
Mohammad Robiul Hossan ◽  
Robert Dillon ◽  
Prashanta Dutta

The colloidal dynamics of bipolar microparticles is of growing theoretical interest in understanding and advancement of electrorheology and ferroelectric research. In this paper we present an interface resolved numerical study to analyze dynamics of ellipsoidal bipolar microparticles for various initial configurations. The bipolarity is imposed by providing surface charges of opposite polarity at the two ends of ellipsoidal particles. The numerical simulations show that in the absence of an external electric field, ellipsoidal particles form a head-to-tail chain or stay apart from each other depending on the inter-particle distance, as well as the magnitude and direction of the inherent polar moment. On the other hand, in presence of an external electric field, the assembly or clustering mechanism primarily depends on the magnitude and direction of the applied electric field. Simulation results also show that the electrorotation process is a function of initial configuration. This comprehensive numerical study will help to better understand the mechanisms of clustering, string formation, and the disaggregation of bipolar microparticles.


2002 ◽  
Vol 16 (17n18) ◽  
pp. 2529-2535
Author(s):  
R. Tao ◽  
X. Xu ◽  
Y. C. Lan

When a strong electric field is applied to a suspension of micron-sized high T c superconducting particles in liquid nitrogen, the particles quickly aggregate together to form millimeter-size balls. The balls are sturdy, surviving constant heavy collisions with the electrodes, while they hold over 106 particles each. The phenomenon is a result of interaction between Cooper pairs and the strong electric field. The strong electric field induces surface charges on the particle surface. When the applied electric field is strong enough, Cooper pairs near the surface are depleted, leading to a positive surface energy. The minimization of this surface energy leads to the aggregation of particles to form balls.


2020 ◽  
Author(s):  
Paolo Raiteri ◽  
Peter Kraus ◽  
Julian Gale

Molecular dynamics simulations of the liquid-liquid interface between water and 1,2-Dichloroethane in the presence of weak external electric fields.<div>The effect of the use of 3D periodic Ewald summation and the effect of the simulation setup are discussed.</div><div>A new simple geometric method for designing the simulation cell is proposed. This method was thoroughly tested shown that it mitigates any artefacts to the use of 3D Ewald summation with external electric field.</div>


2020 ◽  
Author(s):  
Arup Sarkar ◽  
Rajaraman Gopalan

<i>Single-Molecule Magnets have potential applications in several nano-technology applications including in high-dense information storage devices and realization of this potential application lies in enhancing the barrier height for magnetization reversal (U<sub>eff</sub>). Recent literature examples suggest that the maximum values that one can obtain using a ligand field are already accomplished. Here we have explored using a combination of DFT and ab initio CASSCF calculations, the way to enhance the barrier height using an oriented external electric field for top three Single-ion Magnets ([Dy(Py)<sub>5</sub>(O<sup>t</sup>Bu)<sub>2</sub>]<sup>+</sup> (<b>1</b>) and [Er{N(SiMe<sub>3</sub>)<sub>2</sub>}<sub>3</sub>Cl]<sup>-</sup> (<b>2</b>) and [Dy(Cp<sup>Me3</sup>)Cl] (<b>3</b>)). For the first time our study reveals that, for apt molecules, if appropriate direction and value of electric fields are chosen, the barrier height could be enhanced twice that of the limit set by the ligand field. This novel non-chemical-fine tuning approach to modulate the magnetic anisotropy is expected to yield new generation SIMs.</i>


1967 ◽  
Vol 6 (46) ◽  
pp. 505-514 ◽  
Author(s):  
J. Latham ◽  
C. P. R. Saunders

AbstractThe forceFrequired to separate two ice spheres was measured as a function of environmental temperatureT, relative humidityHand the strengthEof the external electric field in which the spheres were situated. It was found that over the entire attainable range ofTandH,Fincreased rapidly with increasingE. The increased adhesion was not accompanied by an increase in the rate of growth of the ice bridge between the two spheres and is explicable in terms of Davis’s (1964) calculations of the purely electrostatic forces between two spheres situated in an electric field. The experiments indicate that the rate of growth of snowflakes in a cloud by means of ice crystal aggregation will be markedly enhanced if the cloud is highly electrified.


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