Influence of the electrolyte composition on the activity and selectivity of electrocatalytic centers

Čolić, Viktor; Pohl, Marcus D.; Scieszka, Daniel; Bandarenka, Aliaksandr S.

doi:10.1016/j.cattod.2015.08.003

Cited by 56 publications

(50 citation statements)

References 122 publications

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“…However, now it is understood that both the reaction rate and selectivity of numerous electrocatalytic processes largely depend on the nature of “spectator species”, i. e. electrolyte components, which are not directly involved into the reaction mechanisms ,,,,. According to the current understanding, these species do not form classical chemical bonds with active centers at the electrode surface ,,,. Among these “spectator species”, alkali metal cations have attracted much scientific attention recently, due to their wide applications in laboratory and industrial fields: for instance it is difficult to prepare aqueous electrolytes with high pH values without them.…”

Section: Figurementioning

confidence: 99%

Influence of Alkali Metal Cations on the Hydrogen Evolution Reaction Activity of Pt, Ir, Au, and Ag Electrodes in Alkaline Electrolytes

et al. 2018

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Fundamental understanding of the influence of so‐called spectator electrolyte species on the catalytic activity of electrodes is considered as a relatively novel direction in electrocatalysis. Numerous recent examples show that seemingly inert electrolyte components drastically influence the performance of catalytic centers. Even alkali metal cations in aqueous electrolytes at high pH values can change the reaction turnover frequency by orders of magnitude, depending on their nature, from Li+ to Cs+. Here, we use several electrodes, namely Pt(polycrystalline), Pt(111), Pt(221), Ir(111), Au(111), and Ag(polycrystalline), in different alkali metal cation‐containing electrolytes to reveal their role in the hydrogen evolution reaction (HER). The HER activity trends of various Pt electrodes, irrespective of their surface structure, correlate with the hydration energy of the corresponding alkali metal cations present in the electrolyte (Li+>Na+>K+>Rb+>Cs+). The trend remains the same for the Ir(111), however, it is reversed for Au(111) and Ag(pc) electrocatalysts.

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Section: Figurementioning

confidence: 99%

Influence of Alkali Metal Cations on the Hydrogen Evolution Reaction Activity of Pt, Ir, Au, and Ag Electrodes in Alkaline Electrolytes

et al. 2018

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“…[3,30] The reason provided for why alkaline pH should be avoided is the increased competition of reactant anionsa nd hydroxide ions for binding sites at the electrode, [37] leadingt od ecreased reactantc onversion efficiency and promotion of oxygen evolution. [3,30] The reason provided for why alkaline pH should be avoided is the increased competition of reactant anionsa nd hydroxide ions for binding sites at the electrode, [37] leadingt od ecreased reactantc onversion efficiency and promotion of oxygen evolution.…”

Section: Kolbe Electrolysis Of Valericacid In Aqueous Solutionmentioning

confidence: 99%

“…[38] On the other hand, it is stated that anodic oxygen evolution during Kolbe electrolysis is mostly inhibited, despite being energeticallyf avored, [39] either by the formation of an oxide layer or ahydrophobic layer composed of organic products on the platinum electrode surface that inhibits electrode-water contact (i.e.,o xygen evolution would not be apredominant side reaction). [37] Further, as no additional supporting electrolyte (except NaOH for pH adjustment)w as added for experimentsa tp H5 or pH 11,t his might have caused transport limitations. The latter are stabilized by the anions in their proximity,a ltogether shiftingt he product composition towards non-Kolbe products.H owever,t his was not found in our study; www.chemsuschem.org the reason forw hich we can only speculate.…”

Section: Kolbe Electrolysis Of Valericacid In Aqueous Solutionmentioning

confidence: 99%

“…[37] When considering the example of Kolbe electrolysis in aqueous solutions, chloridei ons from HCl might produce halogenated hydrocarbon products that are environmentally harmful. [37] When considering the example of Kolbe electrolysis in aqueous solutions, chloridei ons from HCl might produce halogenated hydrocarbon products that are environmentally harmful.…”

Section: Economic Consideration Of Using Supporting Electrolytesmentioning

confidence: 99%

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The Dilemma of Supporting Electrolytes for Electroorganic Synthesis: A Case Study on Kolbe Electrolysis

Stang

Harnisch

2015

ChemSusChem

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Remarkably, coulombic efficiency (CE, about 50 % at 1 Farad equivalent), and product composition resulting from aqueous Kolbe electrolysis are independent of reactor temperature and initial pH value. Although numerous studies on Kolbe electrolysis are available, the interrelations of different reaction parameters (e.g., acid concentration, pH, and especially electrolytic conductivity) are not addressed. A systematic analysis based on cyclic voltammetry reveals that solely the electrolytic conductivity impacts the current-voltage behavior. When using supporting electrolytes, not only their concentration, but also the type is decisive. We show that higher concentrations of KNO3 result in reduced CE and thus in significant increase in electric energy demand per converted molecule, whereas Na2 SO4 allows improved space-time yields. Pros and cons of adding supporting electrolytes are discussed in a final cost assessment.

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“…Furthermore, characterizing a heterogeneous catalyst at the working conditions (temperature, gas pressure, liquid composition, etc.) during catalytic operation would provide a direct relationship between structure–processing–properties . This has driven the interest for introducing in situ methodologies in catalysis research.…”

Section: Introductionmentioning

confidence: 99%

In Situ Transmission Electron Microscopy on Energy‐Related Catalysis

Hwang

Chen

Zhou

et al. 2019

Advanced Energy Materials

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Energy‐related catalytic reactions have been extensively investigated in past years in order to efficiently utilize clean and environmentally benign energy sources. In these systems, the catalysts and the catalyst/active medium interfaces play a crucial role in determining their performance. Thus, understanding the physical and chemical properties of catalysts during reactions is of importance to provide fundamental insights for designing the devices. Transmission electron microscopy can provide tremendous information regarding materials' morphology, microstructure, and chemical properties at nanoscales. With in situ electron microscopy, dynamic processes of catalytic reactions in both gas and liquid environments have been investigated in real time. In this paper, the recent research progress of in situ and operando electron microscopy techniques are introduced with the representative works in energy‐related reactions, including electrochemical catalysis in liquid media and heterogeneous catalysis in gas media. The uniqueness of the specific electron microscopy methods and scientific merits of each work are highlighted. Finally, outlooks on emerging research opportunities are discussed.

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Influence of the electrolyte composition on the activity and selectivity of electrocatalytic centers

Cited by 56 publications

References 122 publications

Influence of Alkali Metal Cations on the Hydrogen Evolution Reaction Activity of Pt, Ir, Au, and Ag Electrodes in Alkaline Electrolytes

Influence of Alkali Metal Cations on the Hydrogen Evolution Reaction Activity of Pt, Ir, Au, and Ag Electrodes in Alkaline Electrolytes

The Dilemma of Supporting Electrolytes for Electroorganic Synthesis: A Case Study on Kolbe Electrolysis

In Situ Transmission Electron Microscopy on Energy‐Related Catalysis

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