Reports of meetings
01 Jan 1970-Vol. 7, Iss: 4, pp 69-70
About: The article was published on 1970-01-01. It has received 612 citations till now.
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TL;DR: The purpose of this Review is to examine the fundamental development of the concept of pseudocapacitance and how it came to prominence in electrochemical energy storage as well as to describe new classes of materials whose electrochemicalEnergy storage behavior can be described as pseudOCapacitive.
Abstract: There is an urgent global need for electrochemical energy storage that includes materials that can provide simultaneous high power and high energy density One strategy to achieve this goal is with pseudocapacitive materials that take advantage of reversible surface or near-surface Faradaic reactions to store charge This allows them to surpass the capacity limitations of electrical double-layer capacitors and the mass transfer limitations of batteries The past decade has seen tremendous growth in the understanding of pseudocapacitance as well as materials that exhibit this phenomenon The purpose of this Review is to examine the fundamental development of the concept of pseudocapacitance and how it came to prominence in electrochemical energy storage as well as to describe new classes of materials whose electrochemical energy storage behavior can be described as pseudocapacitive
767 citations
TL;DR: This Review discusses the efforts undertaken so far to achieve efficient charge transport in MOFs and focuses on four common strategies that have been harnessed toward high conductivities.
Abstract: Metal–organic frameworks (MOFs) are intrinsically porous extended solids formed by coordination bonding between organic ligands and metal ions or clusters. High electrical conductivity is rare in M...
751 citations
TL;DR: This review highlights the most recent progress in developing MOF sensing and switching materials with an emphasis on sensing mechanisms based on electricity, magnetism, ferroelectricity and chromism, and provides insight for the future development of advanced MOF materials as next-generation gas and VOC sensors.
Abstract: Developing efficient sensor materials with superior performance for selective, fast and sensitive detection of gases and volatile organic compounds (VOCs) is essential for human health and environmental protection, through monitoring indoor and outdoor air pollutions, managing industrial processes, controlling food quality and assisting early diagnosis of diseases. Metal–organic frameworks (MOFs) are a unique type of crystalline and porous solid material constructed from metal nodes (metal ions or clusters) and functional organic ligands. They have been investigated extensively for possible use as high performance sensors for the detection of many different gases and VOCs in recent years, due to their large surface area, tunable pore size, functionalizable sites and intriguing properties, such as electrical conductivity, magnetism, ferroelectricity, luminescence and chromism. The high porosity of MOFs allows them to interact strongly with various analytes, including gases and VOCs, thus resulting in easily measurable responses to different physicochemical parameters. Although much of the recent work on MOF-based luminescent sensors have been summarized in several excellent reviews (up to 2018), a comprehensive overview of these materials for sensing gases and VOCs based on chemiresistive, magnetic, ferroelectric, and colorimertic mechanisms is missing. In this review, we highlight the most recent progress in developing MOF sensing and switching materials with an emphasis on sensing mechanisms based on electricity, magnetism, ferroelectricity and chromism. We provide a comprehensive analysis on the MOF–analyte interactions in these processes, which play a key role in the sensing performance of the MOF-based sensors and switches. We discuss in detail possible applications of MOF-based sensing and switching materials in detecting oxygen, water vapor, toxic industrial gases (such as hydrogen sulfide, ammonia, sulfur dioxide, nitrous oxide, carbon oxides and carbon disulfide) and VOCs (such as aromatic and aliphatic hydrocarbons, ketones, alcohols, aldehydes, chlorinated hydrocarbons and N,N′-dimethylformamide). Overall, this review serves as a timely source of information and provides insight for the future development of advanced MOF materials as next-generation gas and VOC sensors.
631 citations
TL;DR: The recent advances in MOF thin films are reviewed, including fabrication and patterning strategies and existing nanotechnology applications, and the most attractive future opportunities as well as the most urgent challenges are listed.
Abstract: Surface-supported metal–organic framework thin films are receiving increasing attention as a novel form of nanotechnology. New deposition techniques that enable the control of the film thickness, homogeneity, morphology, and dimensions with a huge number of metal–organic framework compounds offer tremendous opportunities in a number of different application fields. In response to increasing demands for environmental sustainability and cleaner energy, much effort in recent years has been devoted to the development of MOF thin films for applications in photovoltaics, CO2 reduction, energy storage, water splitting, and electronic devices, as well as for the fabrication of membranes. Although existing applications are promising and encouraging, MOF thin films still face numerous challenges, including the need for a more thorough understanding of the thin-film growth mechanism, stability of the internal and external interfaces, strategies for doping and models for charge carrier transport. In this paper, we review the recent advances in MOF thin films, including fabrication and patterning strategies and existing nanotechnology applications. We conclude by listing the most attractive future opportunities as well as the most urgent challenges.
482 citations
TL;DR: Key advances in the application of 2D materials, from both a historical and analytical perspective, are summarized for four different groups of analytes: gases, volatile compounds, ions, and biomolecules.
Abstract: Electrically–transduced sensors, with their simplicity and compatibility with standard electronic technologies, produce signals that can be efficiently acquired, processed, stored, and analyzed. Two dimensional (2D) nanomaterials, including graphene, phosphorene (BP), transition metal dichalcogenides (TMDCs), and others, have proven to be attractive for the fabrication of high–performance electrically-transduced chemical sensors due to their remarkable electronic and physical properties originating from their 2D structure. This review highlights the advances in electrically-transduced chemical sensing that rely on 2D materials. The structural components of such sensors are described, and the underlying operating principles for different types of architectures are discussed. The structural features, electronic properties, and surface chemistry of 2D nanostructures that dictate their sensing performance are reviewed. Key advances in the application of 2D materials, from both a historical and analytical pers...
443 citations
References
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TL;DR: In this article, the properties of contacts between small spherules of silica are shown to be dependent on the structure and geometry of the carbon surface as determined by electron diffraction and microscopic studies.
Abstract: Microphone carbon has been produced by deposition of pyrolytic carbon films over the surfaces of small spherules of silica. The properties of contacts between these spherules are shown to be dependent on the structure and geometry of the carbon surface as determined by electron diffraction and microscopic studies. The graphite‐like crystallites in pyrolytic carbon surfaces are more or less preferentially oriented with their basal planes parallel to the surface, and the contact properties depend systematically on the degree of orientation. This is explained in terms of the anisotropy in properties of these crystallites which are closely approximated by those of single crystal graphite which were determined. The contact resistance and its temperature coefficient and the ``burning voltage'' for carbon contacts are explicable on this basis. However, the microphonic sensitivity of carbon contacts is independent of the surface structure and depends only on the surface geometry.
61 citations