scholarly journals On the electro-oxidation of small organic molecules: towards a fuel cell catalyst testing platform

2021 ◽  
Author(s):  
Damin Zhang ◽  
Jia Du ◽  
Jonathan Quinson ◽  
Matthias Arenz
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Formic Acid ◽  
Organic Molecules ◽  
Gas Diffusion ◽  
Gas Diffusion Electrode ◽  
Proton Exchange ◽  
Electrochemical Cells ◽  
Small Organic Molecules ◽  
Electro Oxidation

The electrocatalytic oxidation of small organic compounds such as methanol or formic acid has been the subject of numerous investigations in the last decades. The motivation for these studies is often their use as fuel in so-called direct methanol or direct formic acid fuel cells, promising alternatives to hydrogen-fueled proton exchange membrane fuel cells. The fundamental research spans from screening studies to identify the best performing catalyst materials to detailed mechanistic investigations of the reaction pathway. These investigations are commonly performed in standard three electrode electrochemical cells with a liquid supporting electrolyte to which the methanol or formic acid is added. In fuel cell devices, however, no liquid electrolyte will be present, instead membrane electrolytes are used. The question therefore arises, to which extend results from conventional electrochemical cells can be extrapolated to conditions found in fuel cells. We previously developed a gas diffusion electrode setup to mimic “real-life” reaction conditions and study electrocatalysts for oxygen gas reduction or water splitting. It is here demonstrated that the setup is also suitable to investigate the properties of catalysts for the electro-oxidation of small organic molecules. Using the gas diffusion electrode setup, it is seen that employing a catalyst - membrane electrolyte interface as compared to conventional electrochemical cells can lead to significantly different catalyst performances. Therefore, it is recommended to implement gas diffusion electrode setups for the investigation of the electro-oxidation of small organic molecules.

A novel dual catalyst layer structured gas diffusion electrode for enhanced performance of high temperature proton exchange membrane fuel cell

2014 ◽  
Vol 246 ◽  
pp. 63-67 ◽  
Author(s):  
Huaneng Su ◽  
Ting-Chu Jao ◽  
Sivakumar Pasupathi ◽  
Bernard Jan Bladergroen ◽  
Vladimir Linkov ◽  
...  
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Catalyst Layer ◽  
Gas Diffusion ◽  
Gas Diffusion Electrode ◽  
Proton Exchange ◽  
Exchange Membrane

Computational Modelling and Simulation of Proton-Exchange Membrane Fuel Cells (Keynote)

2002 ◽  
Author(s):  
N. Djilali ◽  
T. Berning
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transport Phenomena ◽  
Computational Modelling ◽  
Ambient Air ◽  
Gas Diffusion ◽  
Transport Processes ◽  
Proton Exchange ◽  
Exchange Membrane

Fuel cells (FC’s) are electrochemical devices that convert directly into electricity the chemical energy of reaction of a fuel (usually hydrogen) with an oxidant (usually oxygen from ambient air). The only by-products in a hydrogen fuel cell are heat and water, making this emerging technology the leading candidate for quiet, zero emission energy production. Several types of fuel cell are currently undergoing intense research and development for applications ranging from portable electronics and appliances to residential power generation and transportation. The focus of this lecture is Proton-Exchange Membrane Fuel Cells (PEMFC’s). An electrolyte consisting of a “solid” polymer membrane, low operating temperatures (typically below 90 °C) and a relatively simple design combine to make PEMFC’s particularly well suited to automotive and portable applications. The operation of a fuel cell relies on electrochemical reactions and an array of coupled transport phenomena, including multi-component gas flow, two phase-flow, heat and mass transfer, phase change and transport of charged species. The transport processes take place in variety of media, including porous gas diffusion electrodes and polymer membranes. The fuel cell environment makes it impossible to measure in-situ the quantities of interest to understand and quantify these phenomena, and computational modelling and simulations are therefore poised to play a central role in the development and optimization of fuel cell technology. We provide an overview of the role of various transport phenomena in fuel cell operation and some of the physical and computational modelling challenges they present. The processes will be illustrated through examples of multi-dimensional numerical simulations of Proton-Exchange Membrane Fuel Cells. We close with a perspective on some of the many remaining challenges and future development opportunities.

scholarly journals An Intelligent Approach for Contact Pressure Optimization of PEM Fuel Cell Gas Diffusion Layers

2020 ◽  
Vol 10 (12) ◽  
pp. 4194
Author(s):  
Yongbo Qiu ◽  
Peng Wu ◽  
Tianwei Miao ◽  
Jinqiao Liang ◽  
Kui Jiao ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Contact Pressure ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Optimization Approach ◽  
Fe Model ◽  
Latin Hypercube Design ◽  
Agent Model ◽  
Intelligent Approach

The compression of the gas diffusion layer (GDL) greatly affects the electrochemical performance of proton exchange membrane fuel cells (PEMFCs) by means of both the equivalent value and distribution of contact pressure, which depends on the packing manner of the fuel cell. This work develops an intelligent approach for improving the uniformity and equivalent magnitude of contact pressure on GDLs through optimizing the clamping forces and positions on end plates. A finite element (FE) model of a full-size single fuel cell is developed and correlated against a direct measurement of pressure between the GDL and a bipolar plate. Datasets generated by FE simulations based on the optimal Latin hypercube design are used as a driving force for the training of a radial basis function neural network, so-called the agent model. Once the agent model is validated, iterations for optimization of contact pressure on GDLs are carried out without using the complicated physical model anymore. Optimal design of clamping force and position combination is achieved in terms of better contact pressure, with the designed equivalent magnitude and more uniform distribution. Results indicate the proposed agent-based intelligent optimization approach is available for the packing design of fuel cells, stacks in particular, with significantly higher efficiency.

scholarly journals Effective Technique for Improving Electrical Performance and Reliability of Fuel Cells

2017 ◽  
Vol 8 (4) ◽  
pp. 1868
Author(s):  
A. Albarbar ◽  
M. Alrweq
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Water Content ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Pem Fuel Cells ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
Electrical Performance ◽  
And Performance

To optimise the electrical performance of proton exchange membrane (PEM) fuel cells, a number of factors have to be precisely monitored and controlled. Water content is one of those factors that has great impact on reliability, durability and performance of PEM fuel cells. The difficulty in controlling water content lies in the inability to determine correct level of water accumulated inside the fuel cell. In this paper, a model-based technique, implemented in COMSOL, is presented for monitoring water content in PEM fuel cells. The model predicts, in real time, water content taking account of other processes occurring in gas channels, across gas diffusion layers (GDL), electrodes, and catalyst layer (CL) and within the membrane to minimize voltage losses and performance degradation. The level of water generated is calculated as function of cell’s voltage and current. Model’s performance and accuracy are verified using a transparent 500 mW PEM fuel cell. Results show model predicted current and voltage curves are in good agreement with the experimental measurements. The unique feature of this model is that, no special requirements are needed as only current, and voltage of the PEM fuel cell were measured thus, is expected to pave the path for developing non-intrusive control and monitoring systems for fuel cells.

scholarly journals Direct Liquid Fuel Cells – The Influence of Temperature and Dynamic Instabilities

2020 ◽  
Author(s):  
Jéssica Alves Nogueira ◽  
Hamilton Varela
Keyword(s):  
Fuel Cells ◽  
Formic Acid ◽  
Dimethyl Ether ◽  
Liquid Fuel ◽  
Catalyst Surface ◽  
Proton Exchange ◽  
Experimental Investigations ◽  
Experimental Conditions ◽  
Potential Oscillations ◽  
Electro Oxidation

The interconversion between chemical and electrical energies plays a pivotal role in the challenge for a sustainable future. Proton exchange membrane (PEMFC) based on the electro-oxidation of hydrogen and reduction of oxygen comprise a relatively mature technology of indisputable relevance. Alternatively, some open questions concerning the use of Direct Liquid Fuel Cells (DLFC) call for further experimental investigations on these systems. In this paper we evaluate the temperature effect on DLFCs under conventional and oscillatory conditions. We studied four molecules: methanol, formic acid, ethanol, and dimethyl ether. The use of identical experimental conditions allowed at studying the role of the fuel on the DLFC performance, providing thus reference values for future investigations. Under regular, non-oscillatory regime, we observed for all cases that the overpotential decreases as the temperature increases mainly because water activation on the catalyst surface is facilitated at high temperatures. By mapping the conditions where oscillatory kinetics manifest itself under galvanostatic mode, only the electro-oxidation of dimethyl ether did not exhibit potential oscillations. The relationship between oscillatory frequency and temperature during the methanol and formic acid electro-oxidation followed a conventional Arrhenius dependence, whereas with ethanol there was no straightforward trend, and temperature compensation prevails. The atypical behavior found for ethanol was addressed in terms of its main electrocatalytic poisons: adsorbed CO and acetate. The absence of oscillations during dimethyl ether electro-oxidation was attributed to its weak interaction with the catalyst surface.<br>

Numerical Study and Optimisation of Channel Geometry and Gas Diffusion Layer of a PEM Fuel Cell

2012 ◽  
Author(s):  
Surajudeen O. Obayopo ◽  
Tunde Bello-Ochende ◽  
Josua P. Meyer
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Diffusion Layer ◽  
Proton Exchange Membrane ◽  
Pem Fuel Cell ◽  
Gas Diffusion ◽  
Cell System ◽  
Proton Exchange ◽  
Fuel Cell System ◽  
Exchange Membrane

Fuel cell technology offers a promising alternative to conventional fossil fuel energy sources. Proton exchange membrane fuel cells (PEMFC) in particular have become sustainable choice for the automotive industries because of its low pollution, low noise and quick start-up at low temperatures. Researches are on-going to improve its performance and reduce cost of this class of energy systems. In this work, a novel approach to optimise proton exchange membrane (PEM) fuel cell gas channels in the systems bipolar plates with the aim of globally optimising the overall system net power performance at minimised pressure drop and subsequently low pumping power requirement for the reactant species gas was carried out. In addition, the effect of various gas diffusion layer (GDL) properties on the fuel cell performance was examined. Simulations were done ranging from 0.6 to 1.6 mm for channel width, 0.5 to 3.0 mm for channel depth and 0.1 to 0.7 for the GDL porosity. A gradient based optimisation algorithm is implemented which effectively handles an objective function obtained from a computational fluid dynamics simulation to further enhance the obtained optimum values of the examined multiple parameters for the fuel cell system. The results indicate that effective match of reactant gas channel and GDL properties enhance the performance of the fuel cell system. The numerical results computed agree well with experimental data in the literature. Consequently, the results obtained provide useful information for improving the design of fuel cells.

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