The CO Tolerance of Pt/C and Pt-Ru/C Electrocatalysts in a High-Temperature Electrochemical Cell Used for Hydrogen Separation

This paper describes an experimental evaluation and comparison of Pt/C and Pt-Ru/C electrocatalysts for high-temperature (100–160 °C) electrochemical hydrogen separators, for the purpose of mitigating CO poisoning. The performances of both Pt/C and Pt-Ru/C (Pt:Ru atomic ratio 1:1) were investigated and compared under pure hydrogen and a H2/CO gas mixture at various temperatures. The electrochemically active surface area (ECSA), determined from cyclic voltammetry, was used as the basis for a method to evaluate the performances of the two catalysts. Both CO stripping and the underpotential deposition of hydrogen were used to evaluate the electrochemical surface area. When the H2/CO gas mixture was used, there was a complex overlap of mechanisms, and therefore CO peak could not be used to evaluate the ECSA. Hence, the hydrogen peaks that resulted after the CO was removed from the Pt surface were used to evaluate the active surface area instead of the CO peaks. Results revealed that Pt-Ru/C was more tolerant to CO, since the overlapping reaction mechanism between H2 and CO was suppressed when Ru was introduced to the catalyst. SEM images of the catalysts before and after heat treatment indicated that particle agglomeration occurs upon exposure to high temperatures (>100 °C)

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Significance of char active surface area for appraising the reactivity of low- and high-temperature chars

Fuel ◽

10.1016/0016-2361(87)90353-x ◽

1987 ◽

Vol 66 (12) ◽

pp. 1626-1634 ◽

Cited By ~ 48

Author(s):

M.Rashid Khan

Keyword(s):

High Temperature ◽

Surface Area ◽

Active Surface ◽

Active Surface Area

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Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

10.26434/chemrxiv.7770338.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Kailun Yang ◽

Recep Kas ◽

Wilson A. Smith

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Catalyst Layer ◽

Active Surface ◽

Active Surface Area ◽

High Concentration ◽

Copper Electrodes ◽

Surface Enhanced ◽

Local Current

This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO2 electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO2 electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO2 electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer.

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Reduction of cogging torque of PMBLDC motor by changes in active surface area

IET-UK International Conference on Information and Communication Technology in Electrical Sciences (ICTES 2007) ◽

10.1049/ic:20070648 ◽

2007 ◽

Author(s):

R. Somanatham ◽

P.V.N. Prasad

Keyword(s):

Surface Area ◽

Active Surface ◽

Active Surface Area ◽

Cogging Torque

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Increasing Active Surface Area to Fabricate Ultra-Hydrophobic Surface by Using “Black Silicon” with Bosch Etching Process

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2012.4906 ◽

2012 ◽

Vol 12 (6) ◽

pp. 4919-4927 ◽

Cited By ~ 3

Author(s):

Nithi Atthi ◽

Jakrapong Supadech ◽

Gaetan Dupuy ◽

On-uma Nimittrakoolchai ◽

Apirak Pankiew ◽

...

Keyword(s):

Surface Area ◽

Hydrophobic Surface ◽

Active Surface ◽

Etching Process ◽

Black Silicon ◽

Active Surface Area

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

10.26434/chemrxiv.13047710.v2 ◽

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.

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