Cross Sphere Electrode Reaction: the Case of Hydroxyl Desorption during the Oxygen Reduction Reaction on Pt(111) in Alkaline Media

10.26434/chemrxiv.14579232 ◽

2021 ◽

Author(s):

Yuke Li ◽

Zhi-Feng Liu

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Outer Sphere ◽

Electrode Reaction ◽

Reduction Reaction ◽

Alkaline Media ◽

Ab Initio Molecular Dynamics ◽

Hydroxide Ion ◽

Molecular Dynamics Calculations ◽

Inner Sphere

Hydroxide ion is a common electrolyte when electrode reactions take place in alkaline media. In the case of oxygen reduction reaction on Pt(111), we demonstrate by ab initio molecular dynamics calculations, that the desorption of hydroxyl (OH*) from the electrode surface to form a solvated OH− is a cross sphere process, with the reactant OH* in the inner sphere and the product OH− directly generated in the aqueous outer sphere. Such a mechanism is distinct from the typical inner sphere and outer sphere reactions. It is dictated by the strong hydrogen bonding interactions between a hydroxide ion and water molecules and facilitated by proton transfer through solvation layers. It should play a significant role whenever OH* desorption, or its reverse, OH− adsorption, is involved in an electrochemical reaction

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Cross-Sphere Electrode Reaction: The Case of Hydroxyl Desorption during the Oxygen Reduction Reaction on Pt(111) in Alkaline Media

The Journal of Physical Chemistry Letters ◽

10.1021/acs.jpclett.1c01800 ◽

2021 ◽

pp. 6448-6456

Author(s):

Yuke Li ◽

Zhi-Feng Liu

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Electrode Reaction ◽

Reduction Reaction ◽

Alkaline Media

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Fundamental Mechanistic Understanding of Electrocatalysis of Oxygen Reduction on Pt and Non-Pt Surfaces: Acid versus Alkaline Media

Advances in Physical Chemistry ◽

10.1155/2012/491604 ◽

2012 ◽

Vol 2012 ◽

pp. 1-17 ◽

Cited By ~ 220

Author(s):

Nagappan Ramaswamy ◽

Sanjeev Mukerjee

Keyword(s):

Electron Transfer ◽

Oxygen Reduction ◽

Active Site ◽

Electrode Materials ◽

Strong Dependence ◽

Outer Sphere ◽

Reduction Reaction ◽

Alkaline Media ◽

Wide Range ◽

Inner Sphere

Complex electrochemical reactions such as Oxygen Reduction Reaction (ORR) involving multi-electron transfer is an electrocatalytic inner-sphere electron transfer process that exhibit strong dependence on the nature of the electrode surface. This criterion (along with required stability in acidic electrolytes) has largely limited ORR catalysts to the platinum-based surfaces. New evidence in alkaline media, discussed here, throws light on the involvement of surface-independent outer-sphere electron transfer component in the overall electrocatalytic process. This surface non-specificity gives rise to the possibility of using a wide-range of non-noble metal surfaces as electrode materials for ORR in alkaline media. However, this outer-sphere process predominantly leads only to peroxide intermediate as the final product. The importance of promoting the electrocatalytic inner-sphere electron transfer by facilitation of direct adsorption of molecular oxygen on the active site is emphasized by using pyrolyzed metal porphyrins as electrocatalysts. A comparison of ORR reaction mechanisms between acidic and alkaline conditions is elucidated here. The primary advantage of performing ORR in alkaline media is found to be the enhanced activation of the peroxide intermediate on the active site that enables the complete four-electron transfer. ORR reaction schemes involving both outer- and inner-sphere electron transfer mechanisms are proposed.

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Insights on platinum-carbon catalyst degradation mechanism for oxygen reduction reaction in acidic and alkaline media

Journal of Power Sources ◽

10.1016/j.jpowsour.2020.229356 ◽

2021 ◽

Vol 487 ◽

pp. 229356

Author(s):

Marc Francis Labata ◽

Guangfu Li ◽

Joey Ocon ◽

Po-Ya Abel Chuang

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Degradation Mechanism ◽

Reduction Reaction ◽

Alkaline Media ◽

Carbon Catalyst ◽

Acidic And Alkaline Media

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Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

Nanotechnology Reviews ◽

10.1515/ntrev-2020-0057 ◽

2020 ◽

Vol 9 (1) ◽

pp. 843-852

Author(s):

Hunan Jiang ◽

Jinyang Li ◽

Mengni Liang ◽

Hanpeng Deng ◽

Zuowan Zhou

Keyword(s):

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Current Density ◽

Active Sites ◽

Reduction Reaction ◽

Alkaline Media ◽

Acidic Media ◽

Onset Potential ◽

Acidic And Alkaline Media ◽

The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

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