Electrochemical oxide film formation at noble metals as a surface-chemical process
TL;DR: In this article, the formation of the oxide films can be examined in detail by recording the distinguishable stages in the film's electrochemical reduction in linear-sweep voltammetry which is sensitive down to OH O fractional coverages as low as 0.5% and over time-scales down to 50μs in experiments on time-evolution and transformation of oxide films.
About: This article is published in Progress in Surface Science.The article was published on 1995-08-01. It has received 548 citations till now. The article focuses on the topics: Oxide & Noble metal.
Citations
More filters
TL;DR: Basic techniques and analysis methods to distinguish the capacitive and battery‐like behavior are discussed and guidelines for material selection, the state‐of‐the‐art materials, and the electrode design rules to advanced electrode are proposed.
Abstract: Tremendous efforts have been dedicated into the development of high-performance energy storage devices with nanoscale design and hybrid approaches. The boundary between the electrochemical capacitors and batteries becomes less distinctive. The same material may display capacitive or battery-like behavior depending on the electrode design and the charge storage guest ions. Therefore, the underlying mechanisms and the electrochemical processes occurring upon charge storage may be confusing for researchers who are new to the field as well as some of the chemists and material scientists already in the field. This review provides fundamentals of the similarities and differences between electrochemical capacitors and batteries from kinetic and material point of view. Basic techniques and analysis methods to distinguish the capacitive and battery-like behavior are discussed. Furthermore, guidelines for material selection, the state-of-the-art materials, and the electrode design rules to advanced electrode are proposed.
922 citations
564 citations
TL;DR: In this paper, a variety of bifunctional electrocatalysts with a combination of monofunctional electrodes such as platinum for oxygen reduction and iridium oxide for oxygen evolution for reversible fuel cell applications have been developed.
Abstract: Hydrogen production by electrochemical water electrolysis has received great attention as an alternative technology for energy conversion and storage. The oxygen electrode has a substantial effect on the performance and durability of water electrolyzers and reversible (or regenerative) fuel cells because of its intrinsically slow kinetics for oxygen evolution/reduction and poor durability under harsh operating environments. To improve oxygen kinetics and durability of the electrode, extensive studies for highly active and stable oxygen electrocatalysts have been performed. However, due to the thermodynamic instability of transition metals in acidic media, noble metal compounds have been primarily utilized as electrocatalysts in water electrolyzers and reversible fuel cells. For water electrolyzer applications, single noble metal oxides such as ruthenium oxide and iridium oxide have been studied, and binary or ternary metal oxides have been developed to obtain synergistic effects of each component. On the other hand, a variety of bifunctional electrocatalysts with a combination of monofunctional electrocatalysts such as platinum for oxygen reduction and iridium oxide for oxygen evolution for reversible fuel cell applications have been mainly proposed. Practically, supported iridium oxide-on-platinum, its reverse type, and non-precious metal-supported platinum and iridium bifunctional electrocatalysts have been developed. Recent theoretical calculations and experimental studies in terms of water electrolysis and fuel cell technology suggest the effective ways to cope with current major challenges of cost and durability of oxygen electrocatalysts for technical applications.
479 citations
TL;DR: The redox and electrocatalytic properties of the resulting oxide layers are ascribed to the presence of extended networks of hydrated surface bound oxymetal complexes termed surfaquo groups, presenting a possible unifying concept in water oxidation catalysis.
Abstract: This paper presents a review of the redox and electrocatalytic properties of transition metal oxide electrodes, paying particular attention to the oxygen evolution reaction. Metal oxide materials may be prepared using a variety of methods, resulting in a diverse range of redox and electrocatalytic properties. Here we describe the most common synthetic routes and the important factors relevant to their preparation. The redox and electrocatalytic properties of the resulting oxide layers are ascribed to the presence of extended networks of hydrated surface bound oxymetal complexes termed surfaquo groups. This interpretation presents a possible unifying concept in water oxidation catalysis – bridging the fields of heterogeneous electrocatalysis and homogeneous molecular catalysis.
461 citations
TL;DR: A pertinent review of the literature in alkaline media on noble and non-noble metal electrocatalysts is presented in this article along with experimental results to investigate the rationale behind the so-called kinetic facility.
Abstract: Oxygen reduction reaction (ORR) is generally considered to be more facile in alkaline media compared to its acidic counterparts. The fundamental reasoning for this statement has been quite elusive and not understood very well. A pertinent review of the literature in alkaline media on noble and non-noble metal electrocatalysts is presented here along with experimental results to investigate the rationale behind the so-called kinetic facility in alkaline media. Increasing the pH from 0 to 14 has several effects on the electrode–electrolyte interface in terms of the working electrode potential range, the strength of adsorption of the reaction intermediates, and spectator species. Besides these, the reasons for kinetic facility are investigated from the perspective of the changes in the double layer structure and electrochemical reaction mechanisms in transitioning from acidic to alkaline environment. In this context, specifically adsorbed hydroxyl species are found to promote an outer-sphere electron transfe...
322 citations
References
More filters
Book•
[...]
01 Jan 1959
TL;DR: In this paper, the authors discuss various topics about optics, such as geometrical theories, image forming instruments, and optics of metals and crystals, including interference, interferometers, and diffraction.
Abstract: The book is comprised of 15 chapters that discuss various topics about optics, such as geometrical theories, image forming instruments, and optics of metals and crystals. The text covers the elements of the theories of interference, interferometers, and diffraction. The book tackles several behaviors of light, including its diffraction when exposed to ultrasonic waves.
19,815 citations
[...]
01 Oct 1999
TL;DR: In this article, the authors discuss various topics about optics, such as geometrical theories, image forming instruments, and optics of metals and crystals, including interference, interferometers, and diffraction.
Abstract: The book is comprised of 15 chapters that discuss various topics about optics, such as geometrical theories, image forming instruments, and optics of metals and crystals. The text covers the elements of the theories of interference, interferometers, and diffraction. The book tackles several behaviors of light, including its diffraction when exposed to ultrasonic waves.
19,503 citations
TL;DR: In this paper, eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse is vermessen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt.
Abstract: Wird eine Fremdschicht auf eine zu Dickenscherungsschwingungen angeregte Schwingquarzplatte aufgebracht, so andert sich die Eigenfrequenz der Platte infolge Vergroserung der schwingenden Masse. Da die Frequenzanderung eines Schwingquarzes sehr genau vermessen werden kann, ergibt sich daraus eine sehr empfindliche Methode zur Wagung dunner Schichten. Massenbelegung der Fremdschicht und Frequenzanderung sind einander proportional. Die Proportionalitatskonstante last sich aus der Eigenfrequenz des Schwingquarzes berechnen, so das eine empirische Eichung bei der Schichtwagung mit Schwingquarzen entfallt. Die Genauigkeit des Schichtwageverfahrens ist in erster Linie durch die Temperaturabhangigkeit der Quarzeigenfrequenz begrenzt und betragt bei 1° C zugelassener Temperaturschwankung etwa ±4 · 10−9 g · cm−2. Das entspricht einer mittleren Dicke von 0,4 A bei der Dichte ϱ=1 g · cm−3. Das Verfahren wurde auch zur direkten Wagung einer Masse ausgenutzt (Mikrowagung). Dabei lies sich eine Genauigkeit von 10−10g erreichen.
8,035 citations
01 Jan 1959
7,057 citations