Application of the Electrophoretic Deposition Technique for the Development of Electrodes Containing a Catalyst Layer of Nanostructured Pt-Sn/C for DAFCs

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2991-3002
Author(s):  
D. González-Quijano ◽  
W.J. Pech-Rodríguez ◽  
L.E. Verduzco ◽  
J.I. Escalante-García ◽  
G. Vargas-Gutiérrez ◽  
...  
Keyword(s):  
Electrophoretic Deposition ◽  
Catalyst Layer ◽  
Atomic Ratio ◽  
Composition Analysis ◽  
Carbon Cloth ◽  
Acid Media ◽  
Onset Potential ◽  
Catalyst Layers ◽  
Nanostructured Pt ◽  
Electro Catalytic Activity

AbstractA catalyst layer of Pt-Sn/C (Pt:Sn 1:1 atomic ratio) was deposited on commercial carbon cloth electrodes by electrophoretic deposition (EPD). The Pt-Sn/C nanocatalyst was synthesized by the polyol method. Three current signals were applied: i) continuous direct current (CDC); ii) positive pulsed current (PPC); and iii) asymmetric alternating current (AAC). The chemical composition analysis showed the effect of the applied signal on species transferred onto the carbon cloth to form the catalyst layers. Evaluation by SEM confirmed the effect of deposition-signal on the morphology of the catalyst layer. The CDC signal formed spherical agglomerates with irregular distribution along with carbon fibers over the electrode, showing some cracks. A cross-cut view of the electrode showed that the catalyst penetrated the carbon cloth. Meanwhile, the PPC signal promoted a better deposition of the catalyst layer over the carbon cloth surface, with a thicker and more homogeneous rough layer than CDC. In contrast, the layer developed by the AAC signal showed a morphology similar to that by CDC, suggesting the formation of a layer with low metal loading. The cross-cut view of the AAC electrode showed the formation of a highly rough layer having large areas with limited contact with the carbon cloth fibers. The electro-catalytic activity of the electrodes for the Ethanol Oxidation Reaction (EOR) was studied in acid media. The CDC electrode showed an enhanced performance for the EOR by delivering the highest current density (272 mA mg-1Pt) with the more negative onset potential (341 mV) relative to the PPC and AAC electrodes.

Modeling, Design and Fabrication of Non-Uniform Catalyst Layers for PEM Fuel Cells

2010 ◽  
Author(s):  
R. Roshandel
Keyword(s):  
Fuel Cells ◽  
Catalyst Layer ◽  
Current Density Distribution ◽  
Bipolar Plate ◽  
Pem Fuel Cells ◽  
Electrochemical Kinetics ◽  
Carbon Cloth ◽  
Utilization Factor ◽  
Catalyst Layers ◽  
Plasma Sputtering

Catalyst layers are one of the most important parts of the PEM fuel cells and the cell performance is highly related to its structure. Catalyst layers are generally made by uniform distribution of catalyst on carbon cloth or carbon papers to form electrodes. In this paper, the idea of using non-uniform catalyst layer instead of common uniform catalyst layers is presented and simulated by a two-dimensional steady-state computational model. The model accounts for species transport, electrochemical kinetics, charge transport and current density distribution. A fuel cell test stand is designed and built to facilitate experimental validation of the model. Modeling results show that electrical current in catalyst layer is non-uniform, influenced by the channel-land patterns in bipolar plate geometry. Our simulations results also suggest that some non-uniform catalyst distribution patterns regarding to bipolar plate configuration will improve the performance of the whole catalyst layer by increasing catalyst utilization factor. Therefore, it is necessary to design non-uniform catalyst layers regarding to specific procedure. Plasma sputtering method is used to fabricate non-uniform catalyst layers. In this method, the platinum is deposited on the carbon cloth in the plasma-processing chamber. Indeed, an experimental procedure is presented to facilitate the fabrication of non-uniform catalyst layers by plasma sputtering.

scholarly journals Effect of Stratification of Cathode Catalyst Layers on Durability of Proton Exchange Membrane Fuel Cells

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2975
Author(s):  
Zikhona Nondudule ◽  
Jessica Chamier ◽  
Mahabubur Chowdhury
Keyword(s):  
Fuel Cells ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Catalyst Layer ◽  
Cost Effective ◽  
Proton Exchange ◽  
Membrane Electrode ◽  
Potential Cycling ◽  
Catalyst Layers ◽  
Exchange Membrane

To decrease the cost of fuel cell manufacturing, the amount of platinum (Pt) in the catalyst layer needs to be reduced. In this study, ionomer gradient membrane electrode assemblies (MEAs) were designed to reduce Pt loading without sacrificing performance and lifetime. A two-layer stratification of the cathode was achieved with varying ratios of 28 wt. % ionomer in the inner layer, on the membrane, and 24 wt. % on the outer layer, coated onto the inner layer. To study the MEA performance, the electrochemical surface area (ECSA), polarization curves, and electrochemical impedance spectroscopy (EIS) responses were evaluated under 20, 60, and 100% relative humidity (RH). The stratified MEA Pt loading was reduced by 12% while maintaining commercial equivalent performance. The optimal two-layer design was achieved when the Pt loading ratio between the layers was 1:6 (inner:outer layer). This MEA showed the highest ECSA and performance at 0.65 V with reduced mass transport losses. The integrity of stratified MEAs with lower Pt loading was evaluated with potential cycling and proved more durable than the monolayer MEA equivalent. The higher ionomer loading adjacent to the membrane and the bi-layer interface of the stratified catalyst layer (CL) increased moisture in the cathode CL, decreasing the degradation rate. Using ionomer stratification to decrease the Pt loading in an MEA yielded a better performance compared to the monolayer MEA design. This study, therefore, contributes to the development of more durable, cost-effective MEAs for low-temperature proton exchange membrane fuel cells.

Water Management in PEMFC With Ultra-Thin Catalyst-Layers

2013 ◽  
Author(s):  
Prodip K. Das ◽  
Adam Z. Weber
Keyword(s):  
Water Management ◽  
Proton Exchange Membrane ◽  
Removal Rate ◽  
Catalyst Layer ◽  
Proton Exchange ◽  
Cathode Side ◽  
Water Capacity ◽  
Catalyst Layers ◽  
Modeling Data ◽  
Low Pt Loading

A two-dimensional non-isothermal multi-physics proton-exchange-membrane fuel-cell (PEMFC) modeling has been undertaken to investigate the interplay between the platinum (Pt) loading, water-capacity, water transport and cell performance at low operating temperatures (< 40 °C). Two ultra-thin catalyst layers (CLs), traditional Pt/C with extremely low Pt loading and nano-structured thin-film (NSTF), have been the main focus in the present model. Modeling data are compared with experimental polarization curves for both NSTF and traditional Pt/C CLs. Using the model, the interplay between the inherent CL water-capacity versus its removal rate through either the anode or cathode side of the PEMFC is explored. The controlling parameters for the water removal and accumulation (e.g., thickness of catalyst layer, existence of microporous layer, etc.) are also analyzed and the tradeoff between these parameters elucidated with a path towards efficient water management for ultra-thin CLs.

Novel Miniature DMFC With Monolithic Si Electrodes

2009 ◽  
Author(s):  
Masanori Hayase ◽  
Yosuke Saito
Keyword(s):  
Metal Layer ◽  
Catalyst Layer ◽  
Pt Catalyst ◽  
Galvanic Replacement ◽  
Porous Si ◽  
Si Substrate ◽  
Catalyst Layers ◽  
Novel Structure ◽  
Si Wafer ◽  
Immersion Plating

A through-chip porous Ru-Pt catalyst layer was fabricated on a Si wafer and a novel miniature DMFC (Direct Methanol Fuel Cell) was realized. Recently, we found that porous noble metal layer can be synthesized on Si substrate by immersion plating on a porous Si. In order to realize a DMFC with our novel structure, a porous Ru layer was synthesized on the Si substrate using the immersion plating on the porous Si, then Pt was deposited by galvanic replacement reaction on the porous Ru. The porous Ru-Pt structure showed catalytic activity on methanol oxidization. A through-chip porous Ru-Pt layer was fabricated on a Si wafer by plasma etching and monolithic electrodes with catalyst layers and fuel channels were realized. A preliminary DMFC prototype successfully demonstrated power generation of 2mW/cm2.

Effectiveness factor of Pt utilization in cathode catalyst layer of polymer electrolyte fuel cells

2008 ◽  
Vol 86 (7) ◽  
pp. 657-667 ◽  
Author(s):  
Zetao Xia ◽  
Qianpu Wang ◽  
Michael Eikerling ◽  
Zhongsheng Liu
Keyword(s):  
Fuel Cells ◽  
Polymer Electrolyte ◽  
Catalyst Layer ◽  
Polymer Electrolyte Fuel Cells ◽  
Effectiveness Factor ◽  
Cathode Catalyst ◽  
Catalyst Layers ◽  
Effectiveness Factors ◽  
Cathode Catalyst Layer ◽  
Pt Utilization

In this work, we analyze effectiveness factors of Pt utilization in perfluorosulfonate ionomer (PFSI) bonded thin film cathode catalyst layers of polymer electrolyte fuel cells. We define the effectiveness factor of Pt utilization as the apparent rate of current conversion exhibited by a specific catalyst layer design divided by the ideal rate obtained if all Pt atoms were used equally in electrochemical reactions at the specified electrode overpotential and externally provided reactant concentrations. This definition includes statistical factors at all relevant scales as well as non-uniformities of reaction rate distributions under operation. Our model is based on the random composite agglomerated morphology of the catalyst layer. It accounts for the interplay of transport phenomena and electrochemical kinetics. At the mesoscopic scale, limited effectiveness of Pt utilization in agglomerates is mainly an electrostatic effect. We determined spatial distributions of effectiveness factors of agglomerates in the through-plane direction, and thereafter calculated overall effectiveness factors of the cathode catalyst layer. Our results show that small agglomerate radius, low operating current density, high operating temperature, and high oxygen partial pressure result in high effectiveness factors of Pt utilization. Finally, we compared PFSI-bonded thin film cathode catalyst layers with ultrathin two-phase cathode catalyst layers in terms of effectiveness factors. Including the surface to volume atom ratio of Pt nanoparticles, the two different types of structures exhibit similar effectiveness factors of Pt utilization, which are found to be distinctly below 10%.Key words: polymer electrolyte fuel cells, fuel cell modeling, cathode catalyst layer, Pt utilization, effectiveness factor.

Outstanding electro-catalytic activity of Pt x –(RuO y –CeO2)1−x /C composites towards ethanol oxidation in acid media

2013 ◽  
Vol 43 (9) ◽  
pp. 953-965 ◽  
Author(s):  
Lorenna L. A. Souza ◽  
Gláucia R. O. Almeida ◽  
Lays S. R. Silva ◽  
Franciele O. F. Bergamaski ◽  
Álvaro S. Lima ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ethanol Oxidation ◽  
Acid Media ◽  
Electro Catalytic Activity

A Mathematical Model of Ultra-Thin Catalyst Layer in PEFC

2007 ◽  
Vol 539-543 ◽  
pp. 1397-1402 ◽  
Author(s):  
Qian Pu Wang ◽  
Michael Eikerling ◽  
Da Tong Song ◽  
Zhong Sheng Liu
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Current Distribution ◽  
Catalyst Layer ◽  
Polarization Curves ◽  
Mesoscopic Scale ◽  
Poisson Equations ◽  
Catalyst Layers ◽  
Pt Utilization ◽  
Catalyst Utilization

A mathematical model for an ultra-thin catalyst layer in PEFCs is introduced. It utilizes Nernst-Planck and Poisson equations. Calculated polarization curves are shown to compare favourably with published experimental data for ultra-thin catalyst layers. Aspects of current conversion, reactant, current distribution, and catalyst utilization are explored. The effect of catalyst layers thickness on the Pt utilization is discussed. This study gives us a better understanding of transport and reaction at the mesoscopic scale and it furnishes the directions for optimization of this type of catalyst layer.

scholarly journals Sectional automatic adjustment of catalyst layers in gas and liquid phase reactors

2019 ◽  
Vol 298 ◽  
pp. 00030 ◽  
Author(s):  
Nikolay Merentsov ◽  
Alexander Persidskiy ◽  
Mikhail Topilin ◽  
Alexander Golovanchikov
Keyword(s):  
Liquid Phase ◽  
Diffusion Processes ◽  
Catalyst Layer ◽  
Phase Reaction ◽  
Reaction Products ◽  
New Approach ◽  
Automatic Adjustment ◽  
Catalyst Layers ◽  
And Diffusion ◽  
Catalytic Layers

The paper provides a new approach to the high-quality implementation of gas-liquid and catalytic gas-and liquid-phase reactions in displacement reactors. The authors have described the scheme and algorithm for automatic control of the parameters of the catalyst layer. The authors have developed algorithms (mode) for automatic adjustment of the hydrodynamic and thermal modes of the catalytic section and also the principle of automatic adjustment of the system to a gradual or impulse adjusting mode which in case of liquid-phase reaction products results in active dispersion and mutual mixing of reaction products and sharp activation of hydrodynamic and diffusion processes. The article also covers the main requirements for elastically deformable catalytic layers and the advantages of using metalworking machines wastes as adjustable catalyst layers which will have a very significant environmental effect within the recycling and remarketing program.

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