Designing Sites in Heterogeneous Catalysis: Are We Reaching Selectivities Competitive With Those of Homogeneous Catalysts?

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(9), P. 8594 - 8757

Published: March 3, 2022

A critical review of different prominent nanotechnologies adapted to catalysis is provided, with focus on how they contribute the improvement selectivity in heterogeneous catalysis. Ways modify catalytic sites range from use reversible or irreversible adsorption molecular modifiers immobilization tethering homogeneous catalysts and development well-defined solid surfaces. The latter covers methods for dispersion single-atom within supports as well complex nanostructures, it includes post-modification materials via processes such silylation atomic layer deposition. All these methodologies exhibit both advantages limitations, but all offer new avenues design specific applications. Because high cost most fact that resulting may limited thermal chemical stability, be best aimed at improving selective synthesis value-added chemicals, incorporated organic schemes, other applications are being explored address problems energy production, instance, greener processes. details each approaches discussed, representative examples provided. We conclude some general remarks future this field.

Language: Английский

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A general strategy for heterogenizing olefin polymerization catalysts and the synthesis of polyolefins and composites

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: April 12, 2022

The heterogenization of homogeneous metal complexes on solid supports presents an efficient strategy for bridging catalysts with industrially-preferred heterogeneous catalysts; however, a series drawbacks restrict their implementation in olefin polymerization, particularly copolymerization polar comonomers. In this contribution, we report ionic anchoring that is highly versatile, generally applicable to different systems, and enables strong catalyst-support interactions while tolerating various functional groups. addition greatly enhanced polymerization properties, the supported achieved higher comonomer incorporation than unsupported counterparts. This enabled at high temperatures large scale great control over product morphology, facile synthesis polyolefin composites. More importantly, dispersion fillers matrix produced material properties even low composite loadings. It expected will find applications catalytic systems advanced engineering materials.

Language: Английский

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An Ionic Cluster Strategy for Performance Improvements and Product Morphology Control in Metal-Catalyzed Olefin–Polar Monomer Copolymerization

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(5), P. 2245 - 2254

Published: Jan. 24, 2022

Product morphology control represents a critical challenge for polyolefin production, but it has remained largely unexplored in the field of ethylene-polar monomer copolymerization. Herein, an ionic cluster strategy was designed to product during synthesis polar-functionalized polyolefins via precipitation polymerization. In addition control, simultaneous improvements catalytic copolymerization performance (activities, copolymer molecular weights, and comonomer incorporation ratios) were achieved. These results due less poisoning metal-salt-based comonomers compared with their ester counterparts high local concentration alkene induced by formation. Moreover, is generally applicable various systems, greatly enhances catalyst's thermal stability at temperatures (90-150 °C), enables homopolymerization both terminal internal olefins. Finally, composites (generated from tandem process combining prepolymerization step subsequent polymerization) developed, which showed tunable mechanical properties great potential as compatibilizing agents mixtures other types polymers.

Language: Английский

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‘Catalyst + X’ strategies for transition metal-catalyzed olefin-polar monomer copolymerization

Trends in Chemistry, Journal Year: 2023, Volume and Issue: 5(2), P. 147 - 159

Published: Jan. 7, 2023

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Photoelectrocatalytic reduction of CO2 to formate using immobilized molecular manganese catalysts on oxidized porous silicon

Chem, Journal Year: 2025, Volume and Issue: unknown, P. 102462 - 102462

Published: March 1, 2025

Language: Английский

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Hydrogen‐Bonding‐Induced Heterogenization of Nickel and Palladium Catalysts for Copolymerization of Ethylene with Polar Monomers

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(32), P. 17446 - 17451

Published: May 26, 2021

Abstract The practical synthesis of polar‐functionalized polyolefins using transition‐metal‐catalyzed copolymerization olefins with polar monomers is a challenge; the use heterogeneous catalysts little explored. Herein, we report naphthoquinone‐based nickel (Ni/SiO 2 ) and palladium (Pd/SiO through hydrogen bonding interactions ligands silica surface. Ni/SiO exhibits high activities (up to 2.65×10 6 g mol −1 h during ethylene 5‐hexene‐1‐yl‐acetate, affording high‐molecular‐weight (M n up 630 000) semicrystalline polyethylene (comonomer incorporation 2.8 %), along great morphology control. resulting copolymers possess improved surface properties mechanical properties. Pd/SiO can mediate moderate activity produce tunable comonomer incorporation.

Language: Английский

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Photoresponsive Palladium and Nickel Catalysts for Ethylene Polymerization and Copolymerization

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(41), P. 22195 - 22200

Published: July 27, 2021

Abstract In this contribution, we install an azobenzene functionality in olefin polymerization catalysts and use light to modulate their properties via photoinduced trans – cis isomerization of the moiety. The initially targeted azobenzene‐functionalized α‐diimine palladium nickel are not photoresponsive. To address issue, imine–amine system bearing interrupted conjugation with metal center, a sandwich‐type unit at position covalently far from center were prepared studied. We demonstrate that can be used tune ethylene copolymerization polar comonomers, enabling light‐induced control processes, polymer microstructures properties. More interestingly, light‐mediated property changes attributed ligand electronic effects one steric other.

Language: Английский

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Deciphering Metal–Oxide and Metal–Metal Interplay via Surface Organometallic Chemistry: A Case Study with CO₂ Hydrogenation to Methanol

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(18), P. 6767 - 6780

Published: May 4, 2021

Processes that rely on heterogeneous catalysts underpin the production of bulk chemicals and fuels. In spite this, understanding interplay between structure reactivity these complex materials remains elusive—rendering rational improvement existing systems challenging. Herein, we describe efforts to understand capable selective thermochemical conversion CO2 methanol using a surface organometallic chemistry (SOMC) approach. particular, focus remarkable, but often subtle, roles metal–metal synergy metal–support interfaces in determining many different for methanol. Specifically, explore synthetic analytical strategies systematic study synergistic behaviors multi-component catalytic context hydrogenation, discuss how insights obtained can inform design materials. We also address limitations approach employed opportunities expand upon observations emerging from this work, before attempting establish transposable generalizable trends Cu-based beyond.

Language: Английский

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Enhanced Catalysis Based on the Surface Environment of the Silica-Supported Metal Complex

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(19), P. 11985 - 12018

Published: Sept. 13, 2021

Silica-supported metal complex catalysts have been developed and used for organic transformations. The surface environment around the supported enhances catalysis based on a unique effect. design of linker ligand structure induces formation highly reactive, coordinatively unsaturated silica because isolated environment. In contrast to site-isolation effect, accumulated complexes cocatalysts same facilitate acceleration catalytic reaction by concerted catalysis. immobilization multiactive sites also promotes tandem development products from simple molecules through successive reactions. Surface silanol species originating support participate in control density/location complex/coimmobilized functionality/surface is key factor achievement site-isolation/concerted direct interaction between coimmobilized functionality facilitates reactive species. confinement effect pore accumulation active mesopores, which boosts rate, slightly changes conformation, increases enantioselectivity. electronic one factors affecting organometallic chemistry (SOMC) photooxidation complexes. These effects were detected both homogeneous SOMC. Not only local its but play most important roles enhancing this Review, representative examples silica-supported whose significantly enhanced their long-range are summarized. contributions recent developments spectroscopic techniques, including DNP-enhanced solid-state NMR XAFS, evaluation such interactions, discussed. active, selective, durable

Language: Английский

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Lewis Acid Strength of Interfacial Metal Sites Drives CH₃OH Selectivity and Formation Rates on Cu‐Based CO₂ Hydrogenation Catalysts

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(17), P. 9650 - 9659

Published: Feb. 10, 2021

Abstract CH 3 OH formation rates in CO 2 hydrogenation on Cu‐based catalysts sensitively depend the nature of support and presence promoters. In this context, Cu nanoparticles supported tailored supports (highly dispersed M SiO ; M=Ti, Zr, Hf, Nb, Ta) were prepared via surface organometallic chemistry, their catalytic performance was systematically investigated for to OH. The Lewis acid sites enhances rate, likely originating from stabilization formate methoxy intermediates at periphery nanoparticles, as evidenced by metrics strength detection intermediates. depends sites, described pyridine adsorption enthalpies 13 C chemical shifts ‐OCH coordinated M; these are demonstrated here be a molecular descriptor reactivity hydrogenation.

Language: Английский

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