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.

scholarly journals B‐Cu‐Zn gas diffusion electrodes for CO2 electroreduction to C2+ products at high current densities

2021 ◽  
Author(s):  
Yanfang Song ◽  
Joao R. C. Junqueira ◽  
Nivedita Sikdar ◽  
Denis Öhl ◽  
Stefan Dieckhöfer ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
High Current ◽  
Gas Diffusion Electrodes ◽  
Co2 Electroreduction ◽  
Current Densities

scholarly journals B‐Cu‐Zn gas diffusion electrodes for CO2 electroreduction to C2+ products at high current densities

2021 ◽  
Author(s):  
Yanfang Song ◽  
Joao R. C. Junqueira ◽  
Nivedita Sikdar ◽  
Denis Öhl ◽  
Stefan Dieckhöfer ◽  
...  
Keyword(s):  
Gas Diffusion ◽  
High Current ◽  
Gas Diffusion Electrodes ◽  
Co2 Electroreduction ◽  
Current Densities

scholarly journals An Investigation of Direct Hydrocarbon (Propane) Fuel Cell Performance Using Mathematical Modeling

2018 ◽  
Vol 2018 ◽  
pp. 1-18
Author(s):  
Bhavana Parackal ◽  
Hamidreza Khakdaman ◽  
Yves Bourgault ◽  
Marten Ternan
Keyword(s):  
Fuel Cells ◽  
Current Density ◽  
Reaction Rate ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Polarization Curves ◽  
Limiting Current ◽  
Fuel Cell Performance ◽  
Limiting Current Density ◽  
Current Densities

An improved mathematical model was used to extend polarization curves for direct propane fuel cells (DPFCs) to larger current densities than could be obtained with any of the previous models. DPFC performance was then evaluated using eleven different variables. The variables related to transport phenomena had little effect on DPFC polarization curves. The variables that had the greatest influence on DPFC polarization curves were all related to reaction rate phenomena. Reaction rate phenomena were dominant over the entire DPFC polarization curve up to 100 mA/cm2, which is a value that approaches the limiting current densities of DPFCs. Previously it was known that DPFCs are much different than hydrogen proton exchange membrane fuel cells (PEMFCs). This is the first work to show the reason for that difference. Reaction rate phenomena are dominant in DPFCs up to the limiting current density. In contrast the dominant phenomenon in hydrogen PEMFCs changes from reaction rate phenomena to proton migration through the electrolyte and to gas diffusion at the cathode as the current density increases up to the limiting current density.

scholarly journals Water Activity Regulates CO2 Reduction in Gas-Diffusion Electrodes

2021 ◽  
Author(s):  
Nathan Nesbitt ◽  
Wilson Smith
Keyword(s):  
Gas Phase ◽  
Paradigm Shift ◽  
Reaction Rate ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Equilibrium Potential ◽  
Gas Diffusion Electrodes ◽  
Reaction Thermodynamics ◽  
Current Densities ◽  
Reaction Equilibrium

<p>Electrochemical CO<sub>2</sub> reduction has recently reached current densities as high as 1 A cm<sup>-2</sup>, enabled by improving diffusion of CO<sub>2</sub> from the gas phase to the electrocatalyst by use of gas-diffusion electrodes (GDEs) and by improving electrolyte ionic conductivity with concentrated hydroxide electrolytes (7 M KOH). Despite such high solute concentrations, the dilute electrolyte assumption is commonly used to evaluate the thermodynamics of the system, specifically reaction equilibrium potential and reaction rate expression. Here we establish a paradigm shift by demonstrating how to properly include the activity of water and solutes and highlighting corrections to associated reaction thermodynamics.</p>

scholarly journals CO2 reduction on gas-diffusion electrodes and why catalytic performance must be assessed at commercially-relevant conditions

2019 ◽  
Vol 12 (5) ◽  
pp. 1442-1453 ◽  
Author(s):  
Thomas Burdyny ◽  
Wilson A. Smith
Keyword(s):  
Local Reaction ◽  
Co2 Reduction ◽  
Catalytic Performance ◽  
Gas Diffusion ◽  
High Current ◽  
Gas Diffusion Electrodes ◽  
Current Densities ◽  
Current Practices

The substantial implications of high current densities on the local reaction environment and design of catalysts for electrochemical CO2 reduction are addressed. The presented perspectives also reflect on current practices within the field and offer new opportunities for both future catalyst and system-focused research efforts.

scholarly journals Limiting Current of Oxygen Reduction on Gas‐Diffusion Electrodes for Phosphoric Acid Fuel Cells

1994 ◽  
Vol 141 (11) ◽  
pp. 3114-3119 ◽  
Author(s):  
Li Qingfeng ◽  
Xiao Gang ◽  
H. A. Hjuler ◽  
R. W. Berg ◽  
N. J. Bjerrum
Keyword(s):  
Fuel Cells ◽  
Phosphoric Acid ◽  
Oxygen Reduction ◽  
Gas Diffusion ◽  
Limiting Current ◽  
Gas Diffusion Electrodes ◽  
Phosphoric Acid Fuel Cells

scholarly journals Visualisation and quantification of flooding phenomena in gas diffusion electrodes (GDEs) used for electrochemical CO2 reduction: A combined EDX/ICP–MS approach

2022 ◽  
Author(s):  
Ying Kong ◽  
Huifang Hu ◽  
Menglong Liu ◽  
Yuhui Hou ◽  
Viliam Kolivoska ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Co2 Reduction ◽  
Gas Diffusion ◽  
Reduction Reaction ◽  
Gas Diffusion Electrodes ◽  
Cross Sectional ◽  
Faradaic Efficiency ◽  
Icp Ms ◽  
Electrochemical Co2 Reduction ◽  
Current Densities

The most promising strategy to up-scale the electrochemical CO2 reduction reaction (ec-CO2RR) is based on the use of gas diffusion electrodes (GDEs) that allow current densities close to the range of 1 A/cm2 to be reached. At such high current densities, however, the flooding of the GDE cathode is often observed in CO2 electrolysers. Flooding hinders the access of CO2 to the catalyst, and by thus leaving space for (unwanted) hydrogen evolution, it usually leads to a decrease of the observable Faradaic efficiency of CO2 reduction products. To avoid flooding as much as possible has thus become one of the most important aims of to-date ec-CO2RR engineering, and robust analytical methods that can quantitatively assess flooding are now in demand. As flooding is very closely related to the formation of carbonate salts within the GDE structure, in this paper we use alkali (in particular, potassium) carbonates as a tracer of flooding. We present a novel analytical approach —based on the combination of cross-sectional energy-dispersive X-ray (EDX) mapping and inductively coupled plasma mass spectrometry (ICP--MS) analysis— that can not only visualise, but can also quantitatively describe the electrolysis time dependent flooding in GDEs, leading to a better understanding of electrolyser malfunctions.

scholarly journals PEM Single Cells under Differential Conditions: Full Factorial Parameterization of the ORR and HOR Kinetics and Loss Analysis

2021 ◽  
Author(s):  
Christophe Gerling ◽  
Matthias Hanauer ◽  
Ulrich Berner ◽  
Kaspar Andreas Friedrich
Keyword(s):  
Steady State ◽  
Electrochemical Impedance ◽  
Hydrogen Oxidation ◽  
Single Cells ◽  
Reduction Reaction ◽  
Limiting Current ◽  
Hydrogen Oxidation Reaction ◽  
Wide Range ◽  
Current Densities ◽  
Full Factorial

Abstract The anode and cathode kinetics are parameterized based on differential cell measurements. Systematic parameter variations are evaluated to disentangle the dependencies of the electrochemical impedance spectroscopy (EIS) signatures in H2/H2 mode. We introduce a new CO recovery protocol for both electrodes that enables to accurately characterize the hydrogen oxidation reaction (HOR) kinetics. Then, we demonstrate that a compact Tafel kinetics law captures the oxygen reduction reaction (ORR) kinetics for a full factorial grid of conditions, covering a wide range of relative humidities (rH), temperatures, oxygen partial pressures and current densities. This yields the characteristic activation energy and effective reaction order, and we reconcile models that make different assumptions regarding the rH dependency. Moreover, we analyze O2 transport contributions by steady-state and transient limiting current techniques and heliox measurements. Although the rising uncertainty of loss corrections at high current densities makes it impossible to unambiguously identify an intrinsic potential-dependent change of the Tafel slope, our data support that such effect needs not be considered for steady-state cathodic half-cell potentials above 0.8 V.

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