High temperature proton conductors: Applications in catalytic processes

Kokkofitis, Christos; Ouzounidou, Martha; Skodra, Aglaia; Stoukides, Michael

doi:10.1016/j.ssi.2006.11.010

Cited by 42 publications

(30 citation statements)

References 40 publications

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“…They can be assembled at unprecedentedly large scale with cheap materials and simple processing techniques, lowering the barrier of entry for studying confined ionic behaviours. This, in addition, establishes a readily accessible platform to accelerate discoveries in potential applications of nanofluidics such as sensing, catalysis and energy harvesting [38][39][40] . The work here also provides a new example of collective properties of bulk nanostructured materials, where new ionic transport behaviors emerge upon rational assembly of nanoscale building blocks.…”

Section: Discussionmentioning

confidence: 97%

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

et al. 2015

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Exfoliated two-dimensional (2D) sheets can readily stack to form flexible, free-standing films with lamellar microstructure. The interlayer spaces in such lamellar films form a percolated network of molecularly sized, 2D nanochannels that could be used to regulate molecular transport. Here we report self-assembled clay-based 2D nanofluidic channels with surface charge-governed proton conductivity. Proton conductivity of these 2D channels exceeds that of acid solution for concentrations up to 0.1 M, and remains stable as the reservoir concentration is varied by orders of magnitude. Proton transport occurs through a Grotthuss mechanism, with activation energy and mobility of 0.19 eV and 1.2 Â 10 À 3 cm 2 V À 1 s À 1 , respectively. Vermiculite nanochannels exhibit extraordinary thermal stability, maintaining their proton conduction functions even after annealing at 500°C in air. The ease of constructing massive arrays of stable 2D nanochannels without lithography should prove useful to the study of confined ionic transport, and will enable new ionic device designs.

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Section: Discussionmentioning

confidence: 97%

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

et al. 2015

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“…Moreover, proton -conducting membranes are applicable in electrocatalytic reactors for hydrogenations and dehydrogenations of organic compounds, methane activation, steam electrolysis, water gas shift, ammonia reactions as listed in the review by Kokkofi tis et al ( 2007 ). Several reactor concepts are illustrated in Figure 7.15 .…”

Section: Electrocatalytic Membrane Reactorsmentioning

confidence: 99%

“…Iwahara et al . ( 2004 ) and Kokkofi tis et al . ( 2007 ) published reviews of hydrogen technology using proton -conducting ceramics.…”

Section: Introductionmentioning

confidence: 97%

Solid Electrolyte Membrane Reactors

et al. 2010

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IntroductionThe present chapter introduces a specifi c type of membrane reactor only briefl y mentioned in Chapter 1 . The solid electrolyte membrane reactor s ( SEMR ) -or electrochemical membrane reactors as they also are called -are equipped with ion -conducting membranes, which ideally are impermeable for non -charged reaction species. These reactors operate as electrochemical cells, in which the oxidation and reduction reactions are carried out separately on catalyst/electrodes layers located on the opposite sides of the electrolyte. The development of solid electrolyte membrane reactors has reached a semi -commercial stage in fuel cells, in which the maximal generation of electric energy by the total oxidation of hydrogen or hydrocarbon feeds is the primary goal of operation. Research on chemical reactor applications is strongly concentrated in the high -temperature range using either oxygen ion -or proton -conducting inorganic membranes. Some interesting examples were published recently, investigating proton -conducting polymeric membranes for the production of chemicals.This chapter gives a brief overview on the current status and future trends in the development and application of solid electrolyte reactors equipped with solid electrolyte ( SE ) materials used as membranes in these reactors. Initially the working principle of a solid electrolyte membrane reactor and material aspects are discussed. The second part of the chapter gives a detailed description of the special aspects concerning the modeling of solid electrolyte membrane reactors, as well as the application examples of maleic anhydride ( MA ) synthesis and oxidative dehydrogenation of ethane. Finally the chapter reviews recent papers concerning solid electrolyte membrane reactors applying:• high -temperature oxygen ion conductors, • high -temperature proton conductors, • low -temperature proton conductors.There are some recent review papers, especially written for high -temperature applications, which we would like to recommend to readers interested in more

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“…[10,51] and CO [52] while the reduction of NO x mainly with hydrocarbons under lean burn conditions is the subject of numerous reports [53][54][55][56][57][58]. Several studies also focused on hydrogenations (such as C 2 H 5 OH hydrogenation [10,51]), on the water gas shift (WGS) and reverse WGS reactions [59,60] and on NH 3 decomposition [61]. Table 1 presents all studies carried out during the last 7 years.…”

Section: Electrochemical Promotion Of Reactions With Environmental Anmentioning

confidence: 99%

Recent developments and trends in the electrochemical promotion of catalysis (EPOC)

Katsaounis

2009

J Appl Electrochem

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Electrochemical Promotion of Catalysis (EPOC or NEMCA effect) is one of the most exciting discoveries in Electrochemistry with great impact on many catalytic and electrocatalytic processes. According to the words of John O'M. Bockris, EPOC is a triumph, and the latest in a series of advances in electrochemistry which have come about in the last 30 years. It has been shown with more than 80 different catalytic systems that the catalytic activity and selectivity of conductive catalysts deposited on solid electrolytes can be altered in a very pronounced, reversible and, to some extent, predictable manner by applying electrical currents or potentials (typically up to ±2 V) between the catalyst and a second electronic conductor (counter electrode) also deposited on the solid electrolyte. The induced steady-state change in catalytic rate can be up to 135 9 10 3 % higher than the normal (open-circuit) catalytic rate and up to 3 9 10 5 higher than the steady-state rate of ion supply. EPOC studies in the last 7 years mainly focus on the following four areas: Catalytic reactions with environmental impact (such as reduction of NO x and oxidation of light hydrocarbons), mechanistic studies on the origin of EPOC (using mainly oxygen ion conductors), scale-up pf EPOC reactors for potential commercialization via development of novel compact monolithic reactors and application of EPOC in high or low temperature fuel cells via introduction of the concept of triode fuel cell. The most recent EPOC studies in these areas are discussed in the present review and some of the future trends and aims of EPOC research are presented.

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High temperature proton conductors: Applications in catalytic processes

Cited by 42 publications

References 40 publications

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

Self-assembled two-dimensional nanofluidic proton channels with high thermal stability

Solid Electrolyte Membrane Reactors

Recent developments and trends in the electrochemical promotion of catalysis (EPOC)

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