Surface and Interface Coordination Chemistry Learned from Model Heterogeneous Metal Nanocatalysts: From Atomically Dispersed Catalysts to Atomically Precise Clusters

Chemical Reviews, Journal Year: 2022, Volume and Issue: 123(9), P. 5948 - 6002

Published: Dec. 27, 2022

The surface and interface coordination structures of heterogeneous metal catalysts are crucial to their catalytic performance. However, the complicated make it challenging identify molecular-level structure active sites thus precisely control To address this challenge, atomically dispersed (ADMCs) ligand-protected precise clusters (APMCs) have been emerging as two important classes model in recent years, helping build bridge between homogeneous catalysis. This review illustrates how chemistry these types determines performance from multiple dimensions. section ADMCs starts with local at metal–support interface, then focuses on effects coordinating atoms, including basicity hardness/softness. Studies also summarized discuss cooperativity achieved by dual remote effects. In APMCs, roles ligands supports determining activity, selectivity, stability APMCs illustrated. Finally, some personal perspectives further development for presented.

Language: Английский

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Creating High Regioselectivity by Electronic Metal–Support Interaction of a Single-Atomic-Site Catalyst

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(37), P. 15453 - 15461

Published: Sept. 10, 2021

Ligands are the most commonly used means to control regioselectivity of organic reactions. It is very important develop new regioselective methods for synthesis. In this study, we designed and synthesized a single-atomic-site catalyst (SAC), namely, Cu1-TiC, with strong electronic metal–support interaction (EMSI) effects by studying various reaction mechanisms. π cloud back-donation alkyne on metal catalytic intermediate was enhanced during using transient electron-rich characteristics. way, achieved highly linear-E-type conversion electronically unbiased alkynes completely avoided formation branched isomers (ln:br >100:1, TON up 612, 3 times higher than previously recorded). The structural elements SACs were following requirements synthesis mechanism. Every element in played an role This demonstrated that EMSI, which normally thought be responsible improvement efficiency durability heterogeneous catalysis, now first shows exciting potential regulating homogeneous catalysis.

Language: Английский

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Insights into the Mechanism of Methanol Steam Reforming Tandem Reaction over CeO₂ Supported Single-Site Catalysts

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(31), P. 12074 - 12081

Published: July 30, 2021

We demonstrated how the special synergy between a noble metal single site and neighboring oxygen vacancies provides an "ensemble reaction pool" for high hydrogen generation efficiency carbon dioxide (CO2) selectivity of tandem reaction: methanol steam reforming. Specifically, rate over Ru1/CeO2 catalyst is up to 9360 mol H2 per Ru hour (579 mLH2 gRu–1 s–1) with 99.5% CO2 selectivity. Reaction mechanism study showed that integration O facilitated reaction, which consisted dehydrogenation, water dissociation, subsequent gas shift (WGS) reaction. In addition, strength CO adsorption activation energy difference dehydrogenation WGS play important role in determining activity Our paves way further rational design catalysts at atomic scale. Furthermore, development such highly efficient selective evolution systems promises deliver desirable economic ecological benefits.

Language: Английский

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Single‐Atom Catalysis in Organic Synthesis

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(34)

Published: March 15, 2023

Single-atom catalysts hold the potential to significantly impact chemical sector, pushing boundaries of catalysis in new, uncharted directions. These materials, featuring isolated metal species ligated on solid supports, can exist many coordination environments, all which have shown important functions specific transformations. Their emergence has also provided exciting opportunities for mimicking metalloenzymes and bridging gap between homogeneous heterogeneous catalysis. This Review outlines impressive progress made recent years regarding use single-atom organic synthesis. We illustrate knowledge gaps search more sustainable, earth-abundant synthetic applications.

Language: Английский

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Synergistic Interactions of Neighboring Platinum and Iron Atoms Enhance Reverse Water–Gas Shift Reaction Performance

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(4), P. 2264 - 2270

Published: Jan. 23, 2023

The limitations of conventional strategies in finely controlling the composition and structure demand new promotional effects for upgrading reverse water–gas shift (RWGS) catalysts enhanced fuel production. We report design synthesis a hetero-dual-site catalyst boosting RWGS performance by controllably loading Fe atoms at neighboring Pt atom on surface commercial CeO2. Fe–Pt/CeO2 exhibits remarkably high catalytic (TOFPt: 43,519 h–1) CO2 to CO conversion with ∼100% selectivity relatively low temperature 350 °C. Furthermore, retains over 80% activity after 200 h continuous operation. experimental computational investigations reveal "two-way synergistic effect", where can not only serve as promotors alter charge density but also be activated excess active hydrogen species generated atoms, enhancing stability.

Language: Английский

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Oxidative Redispersion-Derived Single-Site Ru/CeO₂ Catalysts with Mobile Ru Complexes Trapped by Surface Hydroxyls Instead of Oxygen Vacancies

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(8), P. 6028 - 6044

Published: April 8, 2024

Controlling the oxidative redispersion behavior of supported metal nanoparticles is central importance in producing high-performance catalysts applied under industry-related oxidation conditions. So far, considerable efforts have been paid to understanding reactant (including O2)-induced disintegration, while much less known about influences support defects like hydroxyl (OH) and oxygen vacancy (VO) on stabilization metal–reactant complexes. In this article, by using H2 as a reducing agent, roles OH groups VO Ru over CeO2 nanorods were distinguished further disentangled comparison with cases CO-pretreated Ru/CeO2. Supported electron microscopy, situ diffuse reflectance infrared Fourier transform spectroscopy, X-ray photoelectron Raman, other characterizations, we showed that doubly bridging (II) CeO2(111) steps (type II or III) played major stabilizing Ru–Ox complexes atomically dispersed species, surface sites assisted dehydrogenation prevented overcapping reactive sites. The propylene combustion activity thus-obtained single-site Ru/CeO2 was far superior benchmark Pt/Al2O3 catalyst. results suggested well-designed treatments could be used maximize effectiveness (reactant-induced) CeO2, attention should possible when dealing catalysis systems accessible reactants (e.g., hydrogen, water, and/or hydrocarbons) give rise hydroxyls working

Language: Английский

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Selective Hydrogenation of Aldehydes under Syngas Using CeO₂-Supported Au Nanoparticle Catalyst

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(20), P. 14086 - 14094

Published: April 18, 2024

Chemoselective hydrogenation of aldehydes to alcohols is importance in synthetic chemistry. Here, we report a reusable CeO2-supported Au nanoparticle catalyst for the selective using syngas as hydrogen source which CO works site blocker prevent side reactions. In particular, with an easily reducible alkene, alkyne, or halogen moiety under gave corresponding high selectivity, while pure resulted overreduction dehalogenation. Of particular interest that but does not affect rate significantly. A potential application present system was demonstrated by conversion terminal alkenes via one-pot hydroformylation/hydrogenation sequence.

Language: Английский

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Metal-Specific Reactivity in Single-Atom Catalysts: CO Oxidation on 4d and 5d Transition Metals Atomically Dispersed on MgO

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(35), P. 14890 - 14902

Published: Aug. 12, 2020

Understanding and tuning the catalytic properties of metals atomically dispersed on oxides are major stepping-stones toward a rational development single-atom catalysts (SACs). Beyond individual showcase studies, design synthesis structurally regular series SACs opens door to systematic experimental investigations performance as function metal identity. Herein, based various 4d (Ru, Rh, Pd) 5d (Ir, Pt) transition has been synthesized common MgO carrier. Complementary (X-ray absorption spectroscopy) theoretical (Density Functional Theory) studies reveal that, regardless identity, cations occupy preferably octahedral coordination lattice positions under step-edges, hence highly confined by oxide support. Upon exposure O2-lean CO oxidation conditions, FTIR spectroscopy indicates partial deconfinement monatomic centers driven at precatalysis temperatures, followed surface carbonate species steady-state conditions. These findings supported DFT calculations, which show driving force final structure for protrusion be metal-dependent, but point an equivalent octahedral-coordinated M4+ resting state in all cases. Experimentally, apparent reaction activation energies range 96 ± 19 kJ/mol determined, with Pt leading lowest energy barrier. The results indicate sites SACs, differences reactivity enforceable via selection lower magnitude than those evidenced previously through mechanistic involvement adjacent redox carrier, suggesting that chemistry is relevant metal.

Language: Английский

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One‐Pot Cooperation of Single‐Atom Rh and Ru Solid Catalysts for a Selective Tandem Olefin Isomerization‐Hydrosilylation Process

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(14), P. 5806 - 5815

Published: Jan. 6, 2020

Abstract Realizing the full potential of oxide‐supported single‐atom metal catalysts (SACs) is key to successfully bridge gap between fields homogeneous and heterogeneous catalysis. Here we show that one‐pot combination Ru 1 /CeO 2 Rh SACs enables a highly selective olefin isomerization‐hydrosilylation tandem process, hitherto restricted molecular in solution. Individually, monoatomic sites remarkable reaction specificity for double‐bond migration anti ‐Markovnikov α‐olefin hydrosilylation, respectively. First‐principles DFT calculations ascribe such selectivity differences binding strength substrate centers. The single‐pot cooperation two allows production terminal organosilane compounds with high regio‐selectivity (>95 %) even from industrially‐relevant complex mixtures internal olefins, alongside straightforward catalyst recycling reuse. These results demonstrate significance catalytic reactions, which are central intensification chemical processes.

Language: Английский

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A Single‐Atom Cobalt Catalyst for the Fluorination of Acyl Chlorides at Parts‐per‐Million Catalyst Loading

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(40)

Published: Aug. 24, 2022

Improving the stability of sensitive catalytic systems is an emerging research topic in catalysis field. However, current design heterogeneous catalysts mainly improves their performance. This paper presents a single-atom catalyst (SAC) strategy to improve cobalt-catalysed fluorination acyl chlorides. A stable Co-F intermediate can be formed through oxidative Co1 -N4 @NC SAC, which replace unstable high-valent cobalt system and avoid use phosphine ligands. In SAC system, KF employed as fluorinating reagent AgF, applied various substrates scale-up conversion with high turnover numbers (TON=1.58×106 ). work also shows that inorganic SACs have tremendous potential for organofluorine chemistry, it provides good reference follow-up studies on structure-activity relationship between chemical reaction mechanisms.

Language: Английский

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