scholarly journals Effects of Environmental Conditions on Cathode Degradation of Polymer Electrolyte Fuel Cell during Potential Cycle

2019 ◽  
Vol 10 (2) ◽  
pp. 24
Author(s):  
Yoshiyuki Hashimasa ◽  
Hiroshi Daitoku ◽  
Tomoaki Numata
Keyword(s):  
Fuel Cell ◽  
Active Surface ◽  
Carbon Support ◽  
Load Cycle ◽  
Polymer Electrolyte Fuel Cell ◽  
Active Surface Area ◽  
Test Protocol ◽  
Carbon Corrosion ◽  
Durability Test ◽  
Cathode Degradation

We investigated the effects of cell temperature and the humidity of gas supplied to the cell during the load cycle durability test protocol recommended by The Fuel Cell Commercialization Conference of Japan (FCCJ). Changes in the electrochemically active surface area (ECA) and in the amount of carbon support corrosion were examined by using the JARI standard single cell. The ECA declined more quickly when the gas humidity was raised, and the carbon corrosion was at the same level. These results suggest that the agglomeration of platinum was accelerated by the same agglomeration mechanism, i.e., by raising the humidity of the gas supplied to the cell.

scholarly journals Preparation and Electrocatalytic Characteristics Research of Pd/C Catalyst for Direct Ethanol Fuel Cell

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Qiao Xia Li ◽  
Ming Shuang Liu ◽  
Qun Jie Xu ◽  
Hong Min Mao
Keyword(s):  
Fuel Cell ◽  
Average Particle Size ◽  
Active Surface ◽  
Carbon Support ◽  
Catalytic Performance ◽  
Active Surface Area ◽  
Average Particle ◽  
Ethanol Fuel ◽  
Direct Ethanol Fuel Cell ◽  
Electrochemical Active Surface Area

Two kinds of carbon-support 20% Pd/C catalysts for use in direct ethanol fuel cell (DEFC) have been prepared by an impregnation reduction method using NaBH4and NaH2PO2as reductants, respectively, in this study. The catalysts were characterized by XRD and TEM. The results show that the catalysts had been completely reduced, and the catalysts are spherical and homogeneously dispersed on carbon. The electrocatalytic activity of the catalysts was investigated by electrochemical measurements. The results indicate that the catalysts had an average particle size of 3.3 nm and showed the better catalytic performance, when NaBH4was used as the reducing agent. The electrochemical active surface area of Pd/C (NaBH4) was 56.4 m2·g−1. The electrochemical activity of the Pd/C (NaBH4) was much higher than that of Pd/C (NaH2PO2).

Polymer Electrolyte Fuel Cell Degradation through Foreign Cation Contamination, Proton Depletion and Carbon Corrosion

2018 ◽  
Vol 86 (13) ◽  
pp. 407-419 ◽  
Author(s):  
Charles Joseph Banas ◽  
Md. Tanvir Alam Arman ◽  
Md Aman Uddin ◽  
Jaehyung Park ◽  
Leonard J. Bonville ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Polymer Electrolyte Fuel Cell ◽  
Carbon Corrosion ◽  
Foreign Cation

scholarly journals Carbon-supported Platinum Electrocatalysts probed in a Gas Diffusion Setup with Alkaline Environment: how Particle Size and Mesoscopic Environment influence the Degradation Mechanism

2020 ◽  
Author(s):  
Shima Alinejad ◽  
Jonathan Quinson ◽  
Johanna Schröder ◽  
Jacob J. K. Kirkensgaard ◽  
Matthias Arenz
Keyword(s):  
Particle Size ◽  
Degradation Mechanism ◽  
Active Phase ◽  
Active Surface ◽  
Carbon Support ◽  
Gas Diffusion ◽  
Active Surface Area ◽  
Electrochemical Cells ◽  
Co Stripping ◽  
Large Particles

In this work, we investigate the stability of four different types of Pt/C fuel cell catalysts upon applying accelerated degradation tests (ADTs) in a gas diffusion electrode (GDE) setup equipped with an anion exchange membrane (AEM). In contrast to previous investigations exposing the catalysts to liquid electrolyte, the GDE setup provides a realistic three-phase boundary of the reactant gas, catalyst and ionomer which enables reactant transport rates close to real fuel cells. Therefore, the GDE setup mimics the degradation of the catalyst under more realistic reaction conditions as compared to conventional electrochemical cells. Combining the determination of the loss in electrochemically active surface area (ECSA) of the Pt/C catalysts via CO stripping measurements with the change in particle size distribution determined by small-angle X-ray scattering (SAXS) measurements, we demonstrate that i) the degradation mechanism depends on the investigated Pt/C catalyst and might indeed be different to the one observed in conventional electrochemical cells, ii) degradation is increased in an oxygen gas atmosphere (as compared to an inert atmosphere), and iii) the observed degradation mechanism depends on the mesoscopic environment of the active phase. The measurements indicate an increased particle growth if small and large particles are immobilized next to each other on the same carbon support flakes as compared to a simple mix of two catalysts with small and large particles, respectively.

Influence of carbon support on the performance of platinum based oxygen reduction catalysts in a polymer electrolyte fuel cell

2007 ◽  
Vol 37 (12) ◽  
pp. 1429-1437 ◽  
Author(s):  
Jörg Kaiser ◽  
Pavel A. Simonov ◽  
Vladimir I. Zaikovskii ◽  
Christoph Hartnig ◽  
Ludwig Jörissen ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Oxygen Reduction ◽  
Polymer Electrolyte ◽  
Carbon Support ◽  
Polymer Electrolyte Fuel Cell ◽  
Oxygen Reduction Catalysts ◽  
Reduction Catalysts

Using a Stack Shunt to Mitigate Catalyst Support Carbon Corrosion in Polymer Electrolyte Membrane Fuel Cell Stacks During Start-Stop Cycling

2013 ◽  
Vol 11 (1) ◽  
Author(s):  
Denis Bona ◽  
Dennis E. Curtin ◽  
Francesco Pedrazzo ◽  
Elena Maria Tresso
Keyword(s):  
Fuel Cell ◽  
Corrosion Rate ◽  
Degradation Rate ◽  
Catalyst Support ◽  
Catalyst Layer ◽  
Carbon Support ◽  
Ex Situ ◽  
Carbon Oxidation ◽  
Carbon Corrosion ◽  
Voltage Degradation

Carbon black based electrodes are generally recognized as state of the art for PEM fuel cell technology due to the high performance achieved with a relatively low Pt content. However, the catalyst carbon support is prone to carbon oxidation. This leads to a loss of the catalyst area and overall performance, along with a higher mass transport loss due to an increased flooding tendency. This phenomenon is particularly severe when the fuel cell experiences repetitive start-stop cycles. Therefore, specific countermeasures against catalyst layer carbon oxidation are required, especially for automotive and backup power applications, where the startup/shutdown rate is considerably high. The authors evaluated a basic design that uses a stack shunt. A properly modified control protocol, which includes the stack shunt, is able to avoid high cathode potential peaks, which are known to accelerate catalyst carbon support corrosion and its negative effects. During two separate durability tests, one adopting the shunt design and another using nonprotected shutdown, a 24-cell stack was subjected to continuous starts and stops for several months and its performance constantly monitored. The results show that when the shunt is used, there is a 37% reduction in the voltage degradation rate for each startup/shutdown cycle and a two-fold increase in the number of startup/shutdown cycles before an individual cell reached the specified “end of life” voltage criteria. Furthermore, ex situ FE-SEM analysis revealed cathode catalyst layer thinning, which is an indication that the emerging degradation mechanism is the catalyst support carbon corrosion, as expected. This provides further support that the constant voltage degradation rate typically experienced in PEMFCs can be primarily attributed to the catalyst support carbon corrosion rate. The proposed shunt protocol is very cost effective and does not require any substantial changes in the system. For this reason, its adoption is recommended as a viable method to decrease the catalyst support carbon corrosion rate and extend the operating life of the PEMFC stack.

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