Effect of Electrical Double-Layer Overlap on the Electroosmotic Flow in Packed-Capillary Columns

1997 ◽  
Vol 69 (3) ◽  
pp. 361-363 ◽  
Author(s):  
Qian-Hong Wan
Keyword(s):  
Double Layer ◽  
Electrical Double Layer ◽  
Electroosmotic Flow ◽  
Capillary Columns ◽  
Packed Capillary Columns

Study of electroosmotic flow in packed capillary columns

2004 ◽  
Vol 1032 (1-2) ◽  
pp. 141-148 ◽  
Author(s):  
Michał Szumski ◽  
Bogusław Buszewski
Keyword(s):  
Electroosmotic Flow ◽  
Capillary Columns ◽  
Packed Capillary Columns

Electrokinetic-Based Microfluidic Processes in Lab-on-a-Chip Devices

2004 ◽  
Author(s):  
Dongqing Li
Keyword(s):  
Process Control ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Electroosmotic Flow ◽  
Lab On A Chip ◽  
Fundamental Understanding ◽  
On Chip

Most microfluidic processes in lab-on-a-chip devices are electrokinetic processes. Fundamental understanding of the electrokinetic based microfluidic processes is key to the design and process control of lab-on-a-chip devices. This paper will review basics of the electrical double layer field, and three key on-chip microfluidic processes: electroosmotic flow, sample mixing and sample dispensing.

Modeling the Electrical Double Layer to Understand the Reaction Environment in a CO2 Electrocatalytic System

2019 ◽  
Author(s):  
Divya Bohra ◽  
Jehanzeb Chaudhry ◽  
Thomas Burdyny ◽  
Evgeny Pidko ◽  
wilson smith
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Local Reaction ◽  
Reaction Diffusion ◽  
Alkali Metal Cations ◽  
Applied Potential ◽  
Critical Aspect

<p>The environment of a CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) catalyst is intimately coupled with the surface reaction energetics and is therefore a critical aspect of the overall system performance. The immediate reaction environment of the electrocatalyst constitutes the electrical double layer (EDL) which extends a few nanometers into the electrolyte and screens the surface charge density. In this study, we resolve the species concentrations and potential profiles in the EDL of a CO<sub>2</sub>ER system by self-consistently solving the migration, diffusion and reaction phenomena using the generalized modified Poisson-Nernst-Planck (GMPNP) equations which include the effect of volume exclusion due to the solvated size of solution species. We demonstrate that the concentration of solvated cations builds at the outer Helmholtz plane (OHP) with increasing applied potential until the steric limit is reached. The formation of the EDL is expected to have important consequences for the transport of the CO<sub>2</sub> molecule to the catalyst surface. The electric field in the EDL diminishes the pH in the first 5 nm from the OHP, with an accumulation of protons and a concomitant depletion of hydroxide ions. This is a considerable departure from the results obtained using reaction-diffusion models where migration is ignored. Finally, we use the GMPNP model to compare the nature of the EDL for different alkali metal cations to show the effect of solvated size and polarization of water on the resultant electric field. Our results establish the significance of the EDL and electrostatic forces in defining the local reaction environment of CO<sub>2</sub> electrocatalysts.</p>

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