Toward Understanding the Utilization of Oxygen Reduction Electrocatalysts under High Mass Transport Conditions and High Overpotentials

ACS Catalysis ◽  
2021 ◽  
pp. 200-211
Author(s):  
Colleen Jackson ◽  
Xiaoqian Lin ◽  
Pieter B. J. Levecque ◽  
Anthony R. J. Kucernak
Keyword(s):  
Mass Transport ◽  
Oxygen Reduction ◽  
High Mass ◽  
High Overpotentials

The oxygen reduction reaction at the three-phase boundary: nanoelectrodes modified with Ag nanoclusters

2016 ◽  
Vol 193 ◽  
pp. 241-250 ◽  
Author(s):  
Jan Clausmeyer ◽  
Alexander Botz ◽  
Denis Öhl ◽  
Wolfgang Schuhmann
Keyword(s):  
Mass Transport ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
Local Delivery ◽  
Model Systems ◽  
Alkaline Media ◽  
High Mass ◽  
Slow Diffusion ◽  
Ag Nanoclusters

Silver nanoclusters are deposited on bifunctional Θ-shaped nanoelectrodes consisting of a carbon nanoelectrode combined with a hollow nanopipette. The Θ-nanoelectrodes are used as model systems to study interfacial mass transport in gas diffusion electrodes and in particular oxygen-depolarized cathodes (ODC) for the oxygen reduction reaction (ORR) in chlor-alkali electrolysers. By local delivery of O2 gas to the electroactive Ag nanoclusters through the adjacent nanopipette, enhanced currents for the ORR at the Ag nanoparticles are recorded which are not accountable when considering the low solubility and slow diffusion of O2 in highly alkaline media. Instead, local oversaturation of O2 leads to current enhancement at the Ag nanoclusters. Due to the intrinsic high mass transport rates at the nanometric electrodes accompanied by local delivery of reactants, the method generally allows to study electrochemical reactions at single nanoparticles beyond the limitations induced by slow diffusion and low reactant concentration. Kinetic and mechanistic information, for instance derived from Tafel slopes, can be obtained from kinetic regimes not accessible to standard techniques.

scholarly journals Oxygen Reduction Reaction on Polycrystalline Platinum: On the Activity Enhancing Effect of Polyvinylidene Difluoride

Surfaces ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 69-77
Author(s):  
Alessandro Zana ◽  
Gustav Wiberg ◽  
Matthias Arenz
Keyword(s):  
Mass Transport ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Surface Area ◽  
Reduction Reaction ◽  
Proton Exchange ◽  
Rotating Disk Electrode ◽  
Membrane Electrode ◽  
Active Surface Area ◽  
Polyvinylidene Difluoride

There have been several reports concerning the performance improving properties of additives, such as polyvinylidene difluoride (PVDF), to the membrane or electrocatalyst layer of proton exchange membrane fuel cells (PEMFC). However, it is not clear if the observed performance enhancement is due to kinetic, mass transport, or anion blocking effects of the PVDF. In a previous investigation using a thin-film rotating disk electrode (RDE) approach (of decreased complexity as compared to membrane electrode assembly (MEA) tests), a performance increase for the oxygen reduction reaction (ORR) could be confirmed. However, even in RDE measurements, reactant mass transport in the catalyst layer cannot be neglected. Therefore, in the present study, the influence of PVDF is re-examined by coating polycrystalline bulk Pt electrodes by PVDF and measuring ORR activity. The results on polycrystalline bulk Pt indicate that the effects of PVDF on the reaction kinetics and anion adsorption are limited, and that the observed performance increase on high surface area Pt/C most likely is due to an erroneous estimation of the electrochemical active surface area (ECSA) from CO stripping and Hupd.

Subnano Amorphous Fe-Based Clusters with High Mass Activity for Efficient Electrocatalytic Oxygen Reduction Reaction

2019 ◽  
Vol 11 (44) ◽  
pp. 41432-41439 ◽  
Author(s):  
Lingyun Liu ◽  
Xu Zhao ◽  
Renwen Li ◽  
Hui Su ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Reduction Reaction ◽  
High Mass ◽  
Electrocatalytic Oxygen Reduction ◽  
Mass Activity

Hierarchically porous metal-free carbon with record high mass activity for oxygen reduction and Zn-air batteries

2019 ◽  
Vol 7 (16) ◽  
pp. 9831-9836 ◽  
Author(s):  
Yuanhui Cheng ◽  
Yalan Wang ◽  
Qiuli Wang ◽  
Zhijian Liao ◽  
Ningyuan Zhang ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Carbon Materials ◽  
Porous Metal ◽  
Free Carbon ◽  
High Mass ◽  
Hierarchically Porous ◽  
Metal Free ◽  
Mass Activity

A cheap polymer with a robust structure was used to produce metal-free carbon materials with record high mass activity.

scholarly journals Electrocatalyst Performance at the Gas/Electrolyte Interface under High-Mass-Transport Conditions: Optimization of the “Floating Electrode” Method

2020 ◽  
Vol 12 (42) ◽  
pp. 47467-47481
Author(s):  
Xiaoqian Lin ◽  
Christopher M. Zalitis ◽  
Jonathan Sharman ◽  
Anthony Kucernak
Keyword(s):  
Mass Transport ◽  
High Mass ◽  
Electrolyte Interface ◽  
Electrode Method ◽  
Floating Electrode
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