Encapsulated Metal Nanoparticles for Catalysis

Chemical Reviews, Journal Year: 2020, Volume and Issue: 121(2), P. 834 - 881

Published: June 25, 2020

Metal nanoparticles have drawn great attention in heterogeneous catalysis. One challenge is that they are easily deactivated by migration-coalescence during the catalysis process because of their high surface energy. With rapid development nanoscience, encapsulating metal nanoshells or nanopores becomes one most promising strategies to overcome stability issue nanoparticles. Besides, activity and selectivity could be simultaneously enhanced taking advantage synergy between materials as well molecular sieving property materials. In this review, we provide a comprehensive summary recent progress synthesis catalytic properties encapsulated This review begins with an introduction synthetic for different architectures developed date, including encapsulation inorganic oxides carbon, porous (zeolites, metal-organic frameworks, covalent organic frameworks), capsules (dendrimers cages). The advantages then discussed, such recyclability, improved selectivity, strong metal-support interactions, capability enabling tandem catalysis, followed some representative applications thermo-, photo-, electrocatalysis. At end discuss remaining challenges associated our perspectives on future field.

Language: Английский

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High-Entropy Alloys as a Platform for Catalysis: Progress, Challenges, and Opportunities

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(19), P. 11280 - 11306

Published: Sept. 17, 2020

High-entropy alloys (HEAs), which are defined as near-equimolar of five or more elements, attracting ever increasing attention because the unique properties in a variety applications. Recently, HEAs have already exhibited remarkable catalytic performance toward several thermal-driven and electrocatalytic reactions. not only regulate electronic geometric structures to large degree but also serve platform construct catalysts with unexpected performance. Herein, recent advances regarding HEA-based catalysis systematically summarized, special focus on synthetic methods for catalysts, performance, mechanistic understanding. Moreover, challenges future opportunities this research area carefully discussed. A series open questions promising directions be explored proposed, including methods, regulation properties, identification active centers, applications into photocatalysis. This Review provides an overview about progress, challenges, catalysis.

Language: Английский

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Emerging applications of zeolites in catalysis, separation and host–guest assembly

Nature Reviews Materials, Journal Year: 2021, Volume and Issue: 6(12), P. 1156 - 1174

Published: Aug. 24, 2021

Language: Английский

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C(sp ³ )–H functionalizations of light hydrocarbons using decatungstate photocatalysis in flow

Science, Journal Year: 2020, Volume and Issue: 369(6499), P. 92 - 96

Published: July 2, 2020

Direct activation of gaseous hydrocarbons remains a major challenge for the chemistry community. Because intrinsic inertness these compounds, harsh reaction conditions are typically required to enable C(sp3)-H bond cleavage, barring potential applications in synthetic organic chemistry. Here, we report general and mild strategy activate bonds methane, ethane, propane, isobutane through hydrogen atom transfer using inexpensive decatungstate as photocatalyst at room temperature. The corresponding carbon-centered radicals can be effectively trapped by variety Michael acceptors, leading hydroalkylated adducts good isolated yields high selectivity (38 examples).

Language: Английский

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Metal Sites in Zeolites: Synthesis, Characterization, and Catalysis

Chemical Reviews, Journal Year: 2022, Volume and Issue: 123(9), P. 6039 - 6106

Published: Sept. 1, 2022

Zeolites with ordered microporous systems, distinct framework topologies, good spatial nanoconfinement effects, and superior (hydro)thermal stability are an ideal scaffold for planting diverse active metal species, including single sites, clusters, nanoparticles in the framework-associated sites extra-framework positions, thus affording metal-in-zeolite catalysts outstanding activity, unique shape selectivity, enhanced recyclability processes of Brønsted acid-, Lewis metal-catalyzed reactions. Especially, thanks to advances zeolite synthesis characterization techniques recent years, zeolite-confined (denoted as metal@zeolite composites) have experienced rapid development heterogeneous catalysis, owing combination merits both intrinsic properties. In this review, we will present developments strategies incorporating tailoring zeolites advanced identification location, distribution, coordination environment species zeolites. Furthermore, catalytic applications demonstrated, emphasis on composites hydrogenation, dehydrogenation, oxidation Finally, point out current challenges future perspectives precise synthesis, atomic level identification, practical application catalyst system.

Language: Английский

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A hydrophobic FeMn@Si catalyst increases olefins from syngas by suppressing C1 by-products

Science, Journal Year: 2021, Volume and Issue: 371(6529), P. 610 - 613

Published: Feb. 4, 2021

Although considerable efforts have been made in the selective conversion of syngas [carbon monoxide (CO) and hydrogen] to olefins through Fischer-Tropsch synthesis (FTS), ~50% converted CO is transformed into undesired one-carbon molecule (C1) by-products dioxide (CO2) methane (CH4)]. In this study, a core-shell FeMn@Si catalyst with excellent hydrophobicity was designed hinder formation CO2 CH4 The hydrophobic shell protected iron carbide core from oxidation by water generated during FTS shortened retention on surface, restraining side reactions related water. Furthermore, electron transfer manganese atoms boosted olefin production inhibited formation. multifunctional could suppress total selectivity less than 22.5% an yield up 36.6% at 56.1%.

Language: Английский

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Catalytic Hydrogen Production from Methane: A Review on Recent Progress and Prospect

Catalysts, Journal Year: 2020, Volume and Issue: 10(8), P. 858 - 858

Published: Aug. 2, 2020

Natural gas (Methane) is currently the primary source of catalytic hydrogen production, accounting for three quarters annual global dedicated production (about 70 M tons). Steam–methane reforming (SMR) used industrial process production. However, SMR suffers with insufficient activity, low long-term stability, and excessive energy input, mostly due to handling large amount CO2 coproduced. With demand anticipated reach 122.5 tons in 2024, novel upgraded processes are desired more effective utilization precious natural resources. In this review, we summarized major descriptors catalyst reaction engineering compared its derivative technologies, such as dry (DRM), partial oxidation O2, autothermal H2O O2. Finally, discussed new progresses methane conversion: direct decomposition solid carbon selective mild conditions containing liquid organics (i.e., methanol, formic acid, acetic acid), which serve alternative carriers. We hope review will help achieve a whole picture from methane.

Language: Английский

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Applications of Zeolites to C1 Chemistry: Recent Advances, Challenges, and Opportunities

Advanced Materials, Journal Year: 2020, Volume and Issue: 32(44)

Published: July 22, 2020

Abstract C1 chemistry, which is the catalytic transformation of molecules including CO, CO 2 , CH 4 3 OH, and HCOOH, plays an important role in providing energy chemical supplies while meeting environmental requirements. Zeolites are highly efficient solid catalysts used industry. The design development zeolite‐based mono‐, bi‐, multifunctional has led to a booming application chemistry. Combining advantages zeolites metallic species promoted production various hydrocarbons (e.g., methane, light olefins, aromatics, liquid fuels) oxygenates methanol, dimethyl ether, formic acid, higher alcohols) from molecules. key zeolite descriptors that influence performance, such as framework topologies, nanoconfinement effects, Brønsted acidities, secondary‐pore systems, particle sizes, extraframework cations atoms, hydrophobicity hydrophilicity, proximity between acid sites discussed provide deep understanding significance An outlook regarding challenges opportunities for conversion resources using meet emerging demands also presented.

Language: Английский

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Confinement in a Zeolite and Zeolite Catalysis

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(13), P. 2894 - 2904

Published: June 24, 2021

ConspectusZeolites, accompanied by their initial discovery as natural mines and the subsequent large-scale commercial production, have played indispensable roles in various fields such petroleum refining chemical industry. Understanding characteristics of zeolites, contrast to counterparts with similar compositions origin thereof, is always a hot challenging topic. Zeolites are known intrinsic confined systems ordered channels on molecular scale, structural confinement has been proposed explain unique behaviors zeolites. Generally, zeolites can regulate diffusion molecules, leading visible difference transportation ultimate shape-selective catalysis. On other hand, local electric field within zeolite or cages act guest molecules change energy levels. Confinement be simply interpreted from both spatial electronic issues; however, nature ambiguous needs clarified.In this Account, we make concise summary analysis topics catalysis two specific views constraint answer basic questions why what else do First, it shown how construct functional sites including Brønsted acid sites, Lewis extraframework cation entrapped metal oxide aggregates via understand role reactivity. Second, multiple impacts zeolite-catalyzed reactions discussed, which rationally lead several processes, namely, zeolite-confined coordinatively unsaturated cascade reaction space Overall, effects exist already extremely important adsorption Although might many systems, more straightforward thanks well-ordered rigid structure, deriving A fantastic scaffold for constructing isolated spatially electrostatically its matrix. Furthermore, containing well-defined transition-metal treated inorganometallic complexes (i.e., framework ligand ions) catalyze resembling organometallic even metalloenzymes. The strong enough induce assist activation small following working fashion frustrated pairs. tactful utilization confinement, electronically, becomes key robust

Language: Английский

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Electrochemical and Photoelectrochemical Water Oxidation for Hydrogen Peroxide Production

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(19), P. 10469 - 10480

Published: Sept. 16, 2020

Abstract Hydrogen peroxide (H 2 O ), as a green fuel and oxidant, has drawn increasing attention in the energy environmental research. Compared with traditional anthraquinone process, electrochemical (EC) photoelectrochemical (PEC) syntheses of H are cost‐effective environmentally friendly. In order to construct membraneless EC/PEC devices for full synthesis, anodic production by water oxidation, which is less developed than cathodic generation, highly desirable. Here, we review recent developments including fundamental aspects, benchmarking activity evaluation, material/catalyst selection, strategies selectivity, efficiency, accumulation. Furthermore, discuss challenges outlook oxidation production, especially device‐level development, accumulation stability, industrial applications. Our intended stimulate studies further improving production.

Language: Английский

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