Room-Temperature Photooxidation of CH₄ to CH₃OH with Nearly 100% Selectivity over Hetero-ZnO/Fe₂O₃ Porous Nanosheets

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(27), P. 12357 - 12366

Published: June 28, 2022

The huge challenge for CH4 photooxidation into CH3OH lies in the activation of inert C-H bond and inhibition overoxidation. Herein, we design two-dimensional in-plane Z-scheme heterostructures composed two different metal oxides, with efforts to polarize symmetrical molecules strengthen O-H CH3OH. As a prototype, first fabricate ZnO/Fe2O3 porous nanosheets, where high-resolution transmission electron microscopy situ X-ray photoelectron spectroscopy affirm their heterostructure. In Fourier transform infrared spectra paramagnetic resonance demonstrate higher amount ·CH3 radicals relative pristine ZnO which density functional theory calculations validate that high local charge accumulation on Fe sites lowers adsorption energy from 0.14 0.06 eV. Moreover, charge-accumulated polarity through transferring electrons O atoms, confirmed by increased barrier 0.30 2.63 eV *CH3O formation, inhibits homolytic cleavage thus suppresses Accordingly, selectivity over nanosheets reaches up nearly 100% an activity 178.3 μmol-1 gcat-1, outperforming previously reported photocatalysts without adding any oxidants under room temperature ambient pressure.

Language: Английский

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Single Atom Catalysts for Selective Methane Oxidation to Oxygenates

ACS Nano, Journal Year: 2022, Volume and Issue: 16(6), P. 8557 - 8618

Published: May 31, 2022

Direct conversion of methane (CH4) to C1–2 liquid oxygenates is a captivating approach lock carbons in transportable value-added chemicals, while reducing global warming. Existing approaches utilizing the transformation CH4 fuel via tandemized steam reforming and Fischer–Tropsch synthesis are energy capital intensive. Chemocatalytic partial oxidation remains challenging due negligible electron affinity, poor C–H bond polarizability, high activation barrier. Transition-metal stoichiometric catalysts harsh oxidants reaction conditions perform poorly with randomized product distribution. Paradoxically, which active enough break also promote overoxidation, resulting CO2 generation reduced carbon balance. Developing can bonds selectively make useful chemicals at mild vital commercialization. Single atom (SACs) specifically coordinated metal centers on support have displayed intrigued reactivity selectivity for oxidation. SACs significantly reduce induced electrostatic polarization facilitate accelerated rate low temperature. The distinct metal–support interaction stabilize intermediate prevent overoxidation products. present review accounts recent progress field selective oxygenates. chemical nature catalytic sites, effects interaction, stabilization species minimize thoroughly discussed forward-looking perspective improve performance.

Language: Английский

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Retrofitting Zr-Oxo Nodes of UiO-66 by Ru Single Atoms to Boost Methane Hydroxylation with Nearly Total Selectivity

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(24), P. 13169 - 13180

Published: June 6, 2023

Direct selective oxidation of methane (DSOM) to high value-added oxygenates under mild conditions is attracting considerable interest. Although state-of-the-art supported metal catalysts can improve conversion, it still challenging avoid the deep oxygenates. Here, we develop a highly efficient metal-organic frameworks (MOFs)-supported single-atom Ru catalyst (Ru1/UiO-66) for DSOM reaction using H2O2 as an oxidant. It endows nearly 100% selectivity and excellent turnover frequency 185.4 h-1 production The yield order magnitude higher than that on UiO-66 alone several times nanoparticles or other conventional Ru1 catalysts, which show severe CO2 formation. Detailed characterizations density functional theory calculations reveal synergistic effect between electron-deficient site electron-rich Zr-oxo nodes Ru1/UiO-66. responsible activation CH4 via resulting Ru1═O* species, while undertake formation oxygenic radical species produce In particular, retrofitted by prune excess inactive O2 more •OH helping suppress over-oxidation

Language: Английский

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Selective Oxidation of Methane to Methanol over Au/H-MOR

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(23), P. 12928 - 12934

Published: June 2, 2023

Selective oxidation of methane to methanol by dioxygen (O2) is an appealing route for upgrading abundant resource and represents one the most challenging reactions in chemistry due overwhelmingly higher reactivity product (methanol) versus reactant (methane). Here, we report that gold nanoparticles dispersed on mordenite efficiently catalyze selective molecular oxygen aqueous medium presence carbon monoxide. The productivity reaches 1300 μmol gcat-1 h-1 or 280 mmol gAu-1 with 75% selectivity at 150 °C, outperforming catalysts reported under comparable conditions. Both hydroxyl radicals hydroperoxide species participate activation conversion methane, while it shown lower affinity mainly accounts selectivity.

Language: Английский

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A review on sustainable iron oxide nanoparticles: syntheses and applications in organic catalysis and environmental remediation

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(13), P. 7579 - 7655

Published: Jan. 1, 2024

In this review paper, recent developments of iron oxide nanoparticles are highlighted and discussed in the field organic catalysis environmental remediation.

Language: Английский

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Oxidative carbonylation of methane to acetic acid on an Fe-modified ZSM-5 zeolite

Applied Catalysis B Environment and Energy, Journal Year: 2023, Volume and Issue: 329, P. 122549 - 122549

Published: March 1, 2023

Language: Английский

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Efficient CO Electroreduction to Methanol by CuRh Alloys with Isolated Rh Sites

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(11), P. 7170 - 7177

Published: May 11, 2023

Electrochemical carbon monoxide reduction reaction (CORR) is a potential route to produce high value-added products such as methanol but currently still suffers from low partial current densities. Herein, we developed Rh1Cu4 alloy with isolated Rh sites homogeneously distributed inside the Cu framework for CO-to-methanol electrosynthesis. Density functional calculations revealed that these enabled enhanced *H coverage on catalyst and were favorable hydrogenation of *CH2OH, which allowed efficient electrocatalytic CORR toward methanol. The exhibited one highest densities 111.7 ± 12.8 mA·cm–2 Faradaic efficiency production 46.2 5.3%, corresponding rate 0.29 μmol s–1 cm–2. This work suggests exciting opportunities further developing rational catalytic high-performance CO electroreduction products.

Language: Английский

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Synergetic Ni–Ce Active Sites in Mixed Cerium/Zirconium Metal–Organic Framework Nodes for Selective Methane Oxidation into Ethanol

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(14), P. 10427 - 10436

Published: June 26, 2024

The direct oxidation of methane into ethanol with high productivity under mild conditions is a grand challenge. We report the development mixed cerium/zirconium metal–organic framework (MOF) nodes-supported mononuclear nickel(II)-hydroxyl species [Cex/Zry–UiO–Ni(OH)] as efficient heterogeneous catalysts for transformation ethanol. Ni2+ ion in Cex/Zry–UiO–Ni(OH) MOFs coordinates μ4–O–, one hydroxy group, and two neutral carboxylate oxygens, which are directly bonded to Ce4+ at metal-oxo nodes. spectroscopic control experiments theoretical calculations reveal that precise composition mixed-metal node, isolation mono Ni-hydroxyl cooperative Ni–Ce active sites confined within porous UiO-MOFs promote facile C–H activation 80 °C, leading formation •CH3 radicals subsequent C–C coupling pores produce an extraordinarily yield 6521 mmol gNi–1 >93% selectivity, outperforming most current reports. Our mechanistic investigation suggests proceeds via dual catalytic cycle, doping MOF's node proximity between ions lead reversible Ce–Ocarboxylate bond dissociation Ni–(μ2–OH)–Ce formation, key radical turnover limiting step. This work highlights importance metal-MOFs designing well-defined heterobimetallic-supported valorization light alkanes catalysis.

Language: Английский

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Research Progress and Outlook on Photocatalytic Conversion of Methane to Methanol

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(9)

Published: Jan. 3, 2024

Abstract Methane, a main component of natural gas, shale and combustible ice, is widely distributed in nature. The direct conversion efficient utilization methane have become crucial topics within the scientific community. However, two challenges persist this field: activation overoxidation inhibition. Recently, research on subject has reached its pinnacle stage. Herein, we present some works addressing these concerns, particularly employing photocatalytic approaches, with specific focus strategies aimed at enhancing selectivity towards methanol as desired product. Finally, discuss existing propose potential solutions for advancing methane‐to‐methanol technology.

Language: Английский

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Metal–Organic Framework-Encaged Monomeric Cobalt(III) Hydroperoxides Enable Chemoselective Methane Oxidation to Methanol

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(18), P. 11159 - 11168

Published: Aug. 31, 2022

Developing highly efficient catalysts for chemoselective oxidation of methane to methanol under mild conditions is a grand challenge. We report the successful design and synthesis heterogeneous single-site cobalt hydroxide catalyst [Ce-UiO-Co(OH)] supported by nodes cerium metal–organic framework (Ce-UiO-66 MOF), which in partial using hydrogen peroxide at 80 °C, giving an extraordinarily high yield 2166 mmol gcat–1 99% selectivity with turnover number 3250. The Ce-UiO-Co significantly more active selective than its iso-structural zirconium analogue Zr-UiO-Co conversion. Experimental computational studies suggest formation CoIII(η2-hydroperoxide) intermediate coordinating one μ4-O– two neutral carboxylate oxygens Ce4+ oxo within pores Ce-UiO-66, undergoes σ-bond metathesis C–H bond limiting step catalytic cycle. lower activation energy due electron-deficient nature ion Co(η2-O2H) species Ce-UiO nodes, promotes facile via metathesis. This MOF-based holds promise developing molecular electrophilic abundant metal functionalization saturated hydrocarbons.

Language: Английский

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