Binary Gas Diffusion

2011 ◽  
pp. 443-462
Keyword(s):  
Gas Diffusion

Compact and efficient gas diffusion electrodes based on nanoporous alumina membranes for microfuel cells and gas sensors

The Analyst ◽  
2020 ◽  
Vol 145 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Wanda V. Fernandez ◽  
Rocío T. Tosello ◽  
José L. Fernández
Keyword(s):  
Response Times ◽  
Hydrogen Oxidation ◽  
Fast Response ◽  
Gas Diffusion ◽  
Limiting Current ◽  
Gas Diffusion Electrodes ◽  
Nanoporous Alumina ◽  
Alumina Membranes ◽  
Current Densities ◽  
Microfuel Cells

Gas diffusion electrodes based on nanoporous alumina membranes electrocatalyze hydrogen oxidation at high diffusion-limiting current densities with fast response times.

A Porous Medium Model of Alveolar Gas Diffusion

1999 ◽  
Vol 2 (3) ◽  
pp. 263-275 ◽  
Author(s):  
Vladimir Koulich ◽  
Jose L. Lage ◽  
Connie C. W. Hsia ◽  
Robert L. Johnson, Jr.
Keyword(s):  
Porous Medium ◽  
Gas Diffusion ◽  
Medium Model ◽  
Porous Medium Model

Assessment of the soil CO2gradient method for soil CO2efflux measurements: comparison of six models in the calculation of the relative gas diffusion coefficient

Tellus B ◽  
2010 ◽  
Vol 62 (1) ◽  
Author(s):  
Natchaya Pingintha ◽  
Monique Y. Leclerc ◽  
John P. Beasley ◽  
Gengsheng Zhang ◽  
Chuckree Senthong
Keyword(s):  
Diffusion Coefficient ◽  
Gas Diffusion

Transport properties of porous γ-alumina from diffusion in liquids and gases

1988 ◽  
Vol 53 (6) ◽  
pp. 1217-1228
Author(s):  
Petr Uchytil ◽  
Petr Schneider
Keyword(s):  
Liquid Phase ◽  
Pore Structure ◽  
Transport Properties ◽  
Gas Diffusion ◽  
Diffusion In Liquids

Transport characteristics of four porous samples with bidisperse or broad monodisperse pore structure were determined by combination of diffusion and permeation measurements with simple gases and compared with results obtained from diffusion of toluene or α,α,α-trifluorotoluene in cyclohexane in liquid phase. From comparison of both types of results it followed that all pores are decisive for the rate of diffusional transport in liquids, whereas only the wide transport pores are significant in gas diffusion.

O2 transfer kinetics in a whole blood unicellular thin layer

1990 ◽  
Vol 68 (5) ◽  
pp. 1854-1864 ◽  
Author(s):  
E. Heidelberger ◽  
R. B. Reeves
Keyword(s):  
Thin Layer ◽  
Fiber Optics ◽  
Whole Blood ◽  
Gas Flow ◽  
Release Kinetics ◽  
Gas Diffusion ◽  
Attractive Alternative ◽  
Half Time ◽  
O2 Uptake ◽  
Mixing Techniques

A planar monocellular layer of whole blood (WB) sandwiched between two Gore-Tex membranes is used to study O2 uptake and release kinetics at 37 degrees C. Gore-Tex, a highly gas-permeable open mesh of Teflon fibrils (78% porosity, 0.2-microns pore size, 75-microns thick), constrains WB to form a thin film without imposing an appreciable gas diffusion barrier. WB layer thickness, measured by isotope dilution, is 1.7 +/- 0.2 microns. WB films are mounted between fiber optics in a gas flow tube for dual-wavelength (536/558 nm) oxyhemoglobin saturation measurements after a step change in PO2. For isocapnic (6% CO2) step changes in PO2 between 0 and 104 Torr, WB O2 uptake half time is 10.4 +/- 0.9 ms; WB O2 release half time is 20.6 +/- 2.4 ms. Half-time values are half of those previously reported. The thin-layer method reduces erythrocyte diffusion boundary layer error and thereby offers an attractive alternative to classical rapid fluid-mixing techniques.

On multicomponent gas diffusion and coupling concepts for porous media and free flow: a benchmark study

2021 ◽  
Author(s):  
Navid Ahmadi ◽  
Katharina Heck ◽  
Massimo Rolle ◽  
Rainer Helmig ◽  
Klaus Mosthaf
Keyword(s):  
Porous Media ◽  
Gas Diffusion ◽  
Free Flow ◽  
Benchmark Study ◽  
Multicomponent Gas

scholarly journals Investigation of Gas Diffusion Electrode Systems for the Electrochemical CO2 Conversion

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 482
Author(s):  
Hilmar Guzmán ◽  
Federica Zammillo ◽  
Daniela Roldán ◽  
Camilla Galletti ◽  
Nunzio Russo ◽  
...  
Keyword(s):  
Carbon Capture ◽  
Active Sites ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Gas Diffusion Electrode ◽  
Catalyst Loading ◽  
Co2 Conversion ◽  
Atmospheric Conditions ◽  
Electrochemical Co2 Reduction ◽  
Liquid Products

Electrochemical CO2 reduction is a promising carbon capture and utilisation technology. Herein, a continuous flow gas diffusion electrode (GDE)-cell configuration has been studied to convert CO2 via electrochemical reduction under atmospheric conditions. To this purpose, Cu-based electrocatalysts immobilised on a porous and conductive GDE have been tested. Many system variables have been evaluated to find the most promising conditions able to lead to increased production of CO2 reduction liquid products, specifically: applied potentials, catalyst loading, Nafion content, KHCO3 electrolyte concentration, and the presence of metal oxides, like ZnO or/and Al2O3. In particular, the CO productivity increased at the lowest Nafion content of 15%, leading to syngas with an H2/CO ratio of ~1. Meanwhile, at the highest Nafion content (45%), C2+ products formation has been increased, and the CO selectivity has been decreased by 80%. The reported results revealed that the liquid crossover through the GDE highly impacts CO2 diffusion to the catalyst active sites, thus reducing the CO2 conversion efficiency. Through mathematical modelling, it has been confirmed that the increase of the local pH, coupled to the electrode-wetting, promotes the formation of bicarbonate species that deactivate the catalysts surface, hindering the mechanisms for the C2+ liquid products generation. These results want to shine the spotlight on kinetics and transport limitations, shifting the focus from catalytic activity of materials to other involved factors.

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