Zinc Migration Mediates Isolated [PtFe₃] in Zeolite for Propane Dehydrogenation

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 3215 - 3226

Published: Feb. 7, 2025

Structural transformation under in situ reaction conditions plays a vital role heterogeneous catalytic performance, especially caused by metal migration. However, the migration of active components often leads to irreversible structural disruption at high temperatures, which could be associated with deactivation catalysts. Here, we report low-melting-point Zn migration-mediated strategy synthesize ultrastable isolated PtFe3 sites anchored MFI zeolite for propane direct dehydrogenation. The optimized catalyst exhibited superior specific activity 36.5 mol C3H6 molPt–1 s–1 propylene selectivity above 99% 550 °C. Moreover, dehydrogenation remained stable after over 400 h on stream low rate constant 0.001 h–1 industrial 580 In characterizations demonstrated that Fe3+ species were conducive rearrangement electronic configuration unoccupied 5d states Pt atoms form electron-deficient sites. This afford insights into dynamic evolution preparation processes.

Language: Английский

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The green chemistry paradigm in modern organic synthesis

Russian Chemical Reviews, Journal Year: 2023, Volume and Issue: 92(12), P. RCR5104 - RCR5104

Published: Dec. 1, 2023

After the appearance of green chemistry concept, which was introduced in vocabulary early 1990s, its main statements have been continuously developed and modified. Currently, there are 10–12 cornerstones that should form basis for an ideal chemical process. This review analyzes accumulated experience achievements towards design products processes reduce or eliminate use generation hazardous substances. The presents views leading Russian scientists specializing various fields this subject, including homogeneous heterogeneous catalysis, fine basic organic synthesis, electrochemistry, polymer chemistry, based on bio-renewable feedstocks energetic compounds materials. A new approach to quantitative evaluation environmental friendliness by authors is described. <br> bibliography includes 1761.

Language: Английский

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Optimizing the reaction pathway of methane photo-oxidation over single copper sites

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Oct. 21, 2024

Language: Английский

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Direct Methane to Methanol Conversion: An Overview of Non‐Syn Gas Catalytic Strategies

The Chemical Record, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 16, 2025

Abstract Direct methane to methanol conversion is a dream reaction in industrial chemistry, which takes inspiration from the biological production catalysed by monooxygenase enzymes (MMOs). Over years, extensive studies have been conducted on this topic bioengineering MMOs, and tailoring methods isolate MMOs active form. Similarly, remarkable achievements noted other activation strategies such as use of heterogeneous catalysts or molecular catalysts. In review, we outline metabolism performed methanotrophs detail latest advancements site structures catalytic mechanisms both types MMOs. Also, recent progress bioinspired approaches using various catalysts, especially first‐row transition metal zeolites mechanistic insights are discussed. addition, complexes “Periana catalyst” for through methyl ester formation presence strong acids also detailed. Compared zeolites‐mediated field, utilisation application still its nascent phase further research required overcome limitations these effectively.

Language: Английский

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Effect of CO₂ Co-Feeding on the Stabilization of Atomically Dispersed Iron Species over MgAl₂O₄ During Ethane Dehydrogenation Reactions

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(16), P. 11153 - 11163

Published: Aug. 8, 2023

Ethane dehydrogenation provides an opportunity for the effective utilization of shale gas and production ethene. Up to now, it is still a great challenge acquire stable ethane catalyst operated under high temperature reductive atmospheres. In this study, we prepared Fe-based supported on MgAl2O4 with atomically dispersed iron species even after 6 reaction–regeneration cycles. Sheet-like morphology spinel structure beneficial dispersion Fe species. The undergoes reduction, sintering, detachment during reaction, as evidenced by in situ High-Angle Annular Dark-Field Scanning Transmission Electron Microscopy quasi-in 57Fe Mössbauer spectroscopy. By contrast, introduction CO2 leads slow deactivation, where only partial reduction isolated Fe3+ Fe2+ was observed. And activity could be restored simple O2 treatment. current work sheds light design high-efficient catalysts.

Language: Английский

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Strategic assembly of active phases on Co-Fe bimetallic catalysts for efficient Fischer-Tropsch synthesis

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: 494, P. 152936 - 152936

Published: June 11, 2024

Language: Английский

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Zeolite-based materials for greenhouse gas capture and conversion

Science China Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 9, 2024

Language: Английский

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Conversion of Polypropylene into Light Hydrocarbons and Aromatics by Metal Exchanged Zeolite Catalysts

Langmuir, Journal Year: 2024, Volume and Issue: 40(18), P. 9636 - 9650

Published: April 24, 2024

Polyolefins can be converted into C

Language: Английский

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Hydrothermal Aging Enhances Nitrogen Oxide Reduction over Iron-Exchanged Zeolites at 150 °C

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(9), P. 6352 - 6359

Published: Feb. 22, 2024

Ammonia selective catalytic reduction (NH3-SCR) over copper- and iron-exchanged zeolites is a state-of-the-art technology for removal of nitrogen oxides (NOx, NO, NO2) from exhaust emissions but suffers poor low-temperature (i.e., 150 °C) activity. Here we show that hydrothermal aging Fe-beta, Fe-ZSM-5, Fe-ferrierite at 650 °C or higher leads to remarkable increase in NOx conversion ∼30 ∼80% under fast NH3-SCR conditions °C. The practical relevance this finding becomes more evident as an aged Fe-beta/fresh Cu-SSZ-13 composite catalyst exhibits ∼90% conversion. We propose neutral heteronuclear bis-μ-oxo ironaluminum dimer might be created within iron during catalyze ammonium nitrate by NO Density functional theory calculations reveal the activation free energy (125 versus 147 kJ mol–1) reaction with adsorbed NO3– species, rate-determining step reduction, considerably lower on site than well-known mononuclear iron–oxo cation site, thus greatly enhancing overall SCR

Language: Английский

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Zeolite Synthesis in the Presence of Metallosiloxanes for the Quantitative Encapsulation of Metal Species for the Selective Catalytic Reduction (SCR) of NO_x

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(40)

Published: Aug. 16, 2023

Metal encapsulation in zeolitic materials through one-pot hydrothermal synthesis (HTS) is an attractive technique to prepare zeolites with a high metal dispersion. Due its simplicity and the excellent catalytic performance observed for several systems, this method has gained great deal of attention over last few years. While most studies apply synthetic methods involving different organic ligands stabilize under conditions, here we report use metallosiloxanes as alternative precursor. Metallosiloxanes can be synthesized from simple cost-affordable chemicals and, when used combination zeolite building blocks standard lead quantitative loading Thanks structural analogy siloxane TEOS, gel stabilizes by forming bridges that prevent precipitation clustering. When focusing on Fe-encapsulation, demonstrate Fe-MFI obtained exhibit activity NH3 -mediated selective reduction (SCR) NOx along good H2 O/SO2 tolerance. This approach opens new route transition metals within structures.

Language: Английский

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