A scenario for oxygen reduction in alkaline media

Ignaczak, Anna; Nazmutdinov, Renat R.; Goduljan, Aleksej; Pinto, Leandro Moreira de Campos; Juárez, Fernanda; Quaino, Paola; Santos, Elizabeth; Schmickler, Wolfgang

doi:10.1016/j.nanoen.2016.11.009

Cited by 18 publications

(19 citation statements)

References 31 publications

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“…Furthermore, we found that in all solutions there is barely any HPORR activity on perfect Au(111) in the potential regime from 0.5 V to 0.8 V. This is probably because the interaction of H 2 O 2 (or HO 2 − ) with Au(111) is too weak, since the d-band center of Au(111) is ca. 3 eV lower than its Fermi level [3].…”

Section: A Characterization Of the Au(111) Electrodementioning

confidence: 86%

“…The oxygen reduction reaction (ORR) is the primary cathodic reaction in fuel cells. Its high overpotential remains the most critical bottleneck restricting the commercialization of fuel cells [1][2][3]. For reactions such as ORR, which involves the transfer of protons and electrons, variation in the solution pH may have many effects on these reactions [2,4,5]: it may change (i) the thermodynamic equilibrium potential, (ii) the nature and concentration of the reactive species, (iii) the reaction kinetics of electrocatalytic reactions, and (iv) the surface properties, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Hydrogen peroxide (HPO) is one of the possible intermediates of ORR [1][2][3]. On Pt group or Pt-based electrocatalysts, there is a potential range in which ORR is under kinetic and mass transport mixed control.…”

Section: Introductionmentioning

confidence: 99%

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pH effect on oxidation of hydrogen peroxide on Au(111) electrode in alkaline solutions

Wei

Cai

et al. 2018

Chinese Journal of Chemical Physics

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The hydrogen peroxide oxidation reaction (HPOOR) on Au(111) electrode in alkaline solutions with pH values ranging from 10 to 13 was examined systematically. HPOOR activity increased and the slope of the i-E curve decreased with increasing pH. HO 2 − is suggested to be the main reactive intermediate for HPOOR in alkaline media. The fast kinetics for HPOOR in alkaline solution is facilitated by the electrostatic interaction between the positively charged electrode and the reactive anions (i.e., HO 2 − and OH −), which increases the concentration of these reactants and the thermodynamic driving force for HO 2 − oxidation at the reaction plane.

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Section: A Characterization Of the Au(111) Electrodementioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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pH effect on oxidation of hydrogen peroxide on Au(111) electrode in alkaline solutions

Wei

Cai

et al. 2018

Chinese Journal of Chemical Physics

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“…[34] Second, there are several reactions where the PT and ET are decoupled for kinetic reasons. For example, in alkaline ORR pure ET has been proposed as the rate determining step [36,37,38,39]. Recent experiments of ORR on carbon-based materials conclusively demonstrate that ET is the rate-and potential-determining step.…”

Section: Introductionmentioning

confidence: 99%

“…[47] Tunneling contributions are rarely considered in the field of computational electrocatalysis which is mainly due to tradition and methodological difficulties; the computational electrochemistry community has adopted tools and classical transition state theory (TST) from computational heterogenous catalysis where reactions take place at high temperatures and quantum effects are considered negligible. On the other hand, the theoretical electrochemistry community has traditionally considered ET, PT, and PCET in the non-adiabatic, tunneling framework [36,48,49,50,51,52,53,34,54,55,56,57,58,59,60,61,62]. The computational community has been slow in adopting the language and approaches developed in the theory community which has resulted scarcity of first principles study of tunneling in electrochemical environments.…”

Section: Introductionmentioning

confidence: 99%

Grand canonical rate theory for electrochemical and electrocatalytic systems I: General formulation and proton-coupled electron transfer reactions

Melander

2020

Preprint

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Recent Advances in Electrocatalysts for Proton Exchange Membrane Fuel Cells and Alkaline Membrane Fuel Cells

et al. 2021

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kinetics of ORR is around five orders of magnitude slower than that of HOR, thereby requiring a much higher Pt loading in the cathode along with more active and durable ORR electrocatalysts than pure Pt catalysts. [1] This requirement presents challenges for the development of advanced cathode catalysts with lower cost, higher activity and higher durability than Pt. Meanwhile, traditional alkaline fuel cells (AFCs) working on concentrated 30−45% KOH electrolytes gained little attention for decades mainly due to their high sensitivity to atmospheric CO 2 . [2,3] The OH − ions in the electrolyte react with CO 2 and form K 2 CO 3 , which can precipitate out as solid crystals, blocking pores in the electrode and gas diffusion layer. In addition, the consumption of OH − reduces the conductivity of the electrolyte. This issue is addressed by replacing KOH solution with a solid anion exchange membrane (AEM) without mobile cations. An AMFC offers several important advantages over PEMFCs, including: 1) low dissolution rates of catalysts, allowing the use of less expensive Pt-free electrocatalysts; 2) wide selections of materials and components that are stable at high pH; and 3) inexpensive solid electrolytes that do not need fluorinated ionomers. Despite their promise, AMFCs are still in the early development stage and have not been systematically investigated due to the lack of highly conductive and durable AEMs. The recent development of highly conductive The rapid progress of proton exchange membrane fuel cells (PEMFCs) and alkaline exchange membrane fuel cells (AMFCs) has boosted the hydrogen economy concept via diverse energy applications in the past decades. For a holistic understanding of the development status of PEMFCs and AMFCs, recent advancements in electrocatalyst design and catalyst layer optimization, along with cell performance in terms of activity and durability in PEMFCs and AMFCs, are summarized here. The activity, stability, and fuel cell performance of different types of electrocatalysts for both oxygen reduction reaction and hydrogen oxidation reaction are discussed and compared. Research directions on the further development of active, stable, and low-cost electrocatalysts to meet the ultimate commercialization of PEMFCs and AMFCs are also discussed.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202006292.

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A scenario for oxygen reduction in alkaline media

Cited by 18 publications

References 31 publications

pH effect on oxidation of hydrogen peroxide on Au(111) electrode in alkaline solutions

pH effect on oxidation of hydrogen peroxide on Au(111) electrode in alkaline solutions

Grand canonical rate theory for electrochemical and electrocatalytic systems I: General formulation and proton-coupled electron transfer reactions

Recent Advances in Electrocatalysts for Proton Exchange Membrane Fuel Cells and Alkaline Membrane Fuel Cells

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