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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Homogeneity of Supported Single‐Atom Active Sites Boosting the Selective Catalytic Transformations

Advanced Science, Journal Year: 2022, Volume and Issue: 9(24)

Published: July 9, 2022

Selective conversion of specific functional groups to desired products is highly important but still challenging in industrial catalytic processes. The adsorption state surface species the key factor modulating groups, which correspondingly determined by uniformity active sites. However, non-identical number metal atoms, geometric shape, and morphology conventional nanometer-sized particles/clusters normally lead non-uniform sites with diverse configurations local coordination environments, causes distinct states species. Hence, it modulate homogeneity so that transformations can be better confined direction. In this review, construction strategies characterization techniques uniform are atomically dispersed on various supports examined. particular, their unique behavior boosting performance chemical discussed, including selective hydrogenation, oxidation, Suzuki coupling, other reactions. addition, dynamic evolution under reaction conditions utilization single-atom catalysts highlighted. Finally, current challenges frontiers identified, perspectives flourishing field provided.

Language: Английский

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Metal–organic frameworks as catalysts and biocatalysts for methane oxidation: The current state of the art

Coordination Chemistry Reviews, Journal Year: 2023, Volume and Issue: 481, P. 215042 - 215042

Published: Feb. 9, 2023

Language: Английский

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Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(10), P. 5888 - 5898

Published: Feb. 14, 2023

The selective oxidation of CH4 in the aqueous phase to produce valuable chemicals has attracted considerable attention due its mild reaction conditions and simple process. As most widely studied catalyst for this reaction, Fe-ZSM-5 demonstrates high intrinsic activity selectivity; however, prepared using conventional methods a limited number active Fe sites, resulting low conversion per unit mass catalyst. This study reports facile organic-template-free synthesis strategy that enables incorporation more into zeolite framework with higher dispersion degree compared methods. Because incorporated way is readily transformed isolated extra-framework species under thermal treatment, overall effect method (Fe-HZ5-TF) 3 times as many catalytically sites Fe-ZSM-5. When used 0.5 M H2O2 at 75 °C, Fe-HZ5-TF produced C1 oxygenate yield 109.4 mmol gcat-1 h-1 (a HCOOH selectivity 91.1%), surpassing other catalysts reported date. Spectroscopic characterization density functional theory calculations revealed are mononuclear form [(H2O)3Fe(IV)═O]2+ bound Al pairs framework. differs from Fe-ZSM-5, where binuclear acts site. Analysis product evolution during suggests radical-driven pathway explain activation site subsequent oxygenates.

Language: Английский

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Photodriven Methane Conversion on Transition Metal Oxide Catalyst: Recent Progress and Prospects

Advanced Science, Journal Year: 2023, Volume and Issue: 11(8)

Published: Oct. 26, 2023

Methane as the main component in natural gas is a promising chemical raw material for synthesizing value-added chemicals, but its harsh conversion process often causes severe energy and environment concerns. Photocatalysis provides an attractive path to active convert methane into various products under mild conditions with clean sustainable solar energy, although many challenges remain at present. In this review, recent advances photocatalytic are systematically summarized. As basis of conversion, activation first elucidated from structural molecules. The study committed categorizing elucidating research progress laws intricate reactions according target products, including partial oxidation, reforming, coupling, combustion, functionalization. Advanced reactor designs also designed enrich options reliability performance evaluation. prospects discussed, which turn offers guidelines methane-conversion-related photocatalyst exploration, reaction mechanism investigation, advanced photoreactor design.

Language: Английский

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Regulating Au coverage for the direct oxidation of methane to methanol

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

Published: Jan. 17, 2024

Abstract The direct oxidation of methane to methanol under mild conditions is challenging owing its inadequate activity and low selectivity. A key objective improving the selective first carbon-hydrogen bond methane, while inhibiting remaining bonds ensure high yield selectivity methanol. Here we design ultrathin Pd x Au y nanosheets revealed a volcano-type relationship between binding strength hydroxyl radical on catalyst surface catalytic performance using experimental density functional theory results. Our investigations indicate trade-off reaction-triggering reaction-conversion steps in reaction process. optimized 3 1 exhibits production rate 147.8 millimoles per gram hour, with 98% at 70 °C, representing one most efficient catalysts for

Language: Английский

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Tandem Catalysis for Selective Oxidation of Methane to Oxygenates Using Oxygen over PdCu/Zeolite

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(24)

Published: April 1, 2022

Selective oxidation of methane to oxygenates with O2 under mild conditions remains a great challenge. Here we report ZSM-5 (Z-5) supported PdCu bimetallic catalyst (PdCu/Z-5) for conversion by reacting in the presence H2 at low temperature (120 °C). Benefiting from co-existence PdO nanoparticles and Cu single atoms via tandem catalysis, PdCu/Z-5 exhibited high yield 1178 mmol g-1Pd h-1 (mmol per gram Pd hour) same time selectivity up 95 %. Control experiments mechanistic studies revealed that promoted situ generation , while not only accelerated activation abundant hydroxyl radicals (⋅OH) decomposition, but also enabled homolytic cleavage CH4 ⋅OH methyl (⋅CH3 ). Subsequently, reacted quickly ⋅CH3 form CH3 OH selectivity.

Language: Английский

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Dynamic Evolution of Zeolite Framework and Metal-Zeolite Interface

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(9), P. 5060 - 5076

Published: April 14, 2022

Zeolites and metal-zeolites are a class of porous materials that have been widely utilized in industry. So far, several fundamental questions relating to the dynamic evolution zeolite framework metal-zeolite interface remain unanswered. Contrary classical view zeolites as static, rigid, changeless material, atoms foreign metals can dynamically interconvert under pretreatment or reaction conditions, making it difficult identify real active centers mechanisms. With development characterization techniques theoretical calculations, more profound understanding at atomic scale has achieved. This critical Review will feature recent progress metal-zeolites, mainly focusing on T–O–T bonds breaking formation, metal valence state transformation, phase evolution, migration. We compare these proposed mechanisms analyze their suitability distinct experimental conditions. highlight identification sites catalytic mechanism should be cautious consider Finally, we summarize usages limitations different characteristic techniques, propose some future research directions about hope bridge gaps between knowledge achieved characterizations nature guide zeolite-based synthesis, modification, application.

Language: Английский

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Atomically Dispersed Nickel Anchored on a Nitrogen‐Doped Carbon/TiO₂Composite for Efficient and Selective Photocatalytic CH₄Oxidation to Oxygenates

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(4)

Published: Nov. 30, 2022

Direct photocatalytic oxidation of methane to liquid oxygenated products is a sustainable strategy for valorization at room temperature. However, in this reaction, noble metals are generally needed function as cocatalysts obtaining adequate activity and selectivity. Here, we report atomically dispersed nickel anchored on nitrogen-doped carbon/TiO2 composite (Ni-NC/TiO2 ) highly active selective catalyst photooxidation CH4 C1 oxygenates with O2 the only oxidant. Ni-NC/TiO2 exhibits yield 198 μmol 4 h selectivity 93 %, exceeding that most reported high-performance photocatalysts. Experimental theoretical investigations suggest single-atom Ni-NC sites not enhance transfer photogenerated electrons from TiO2 isolated Ni atoms but also dominantly facilitate activation form key intermediate ⋅OOH radicals, which synergistically lead substantial enhancement both

Language: Английский

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Recognizing the best catalyst for a reaction

Nature Reviews Chemistry, Journal Year: 2023, Volume and Issue: 7(4), P. 287 - 295

Published: Feb. 23, 2023

Language: Английский

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