Design principles of operando ultraviolet-visible and electron paramagnetic resonance spectroscopy setups for active site characterization in ion-exchanged zeolites DOI Creative Commons
Jörg W. A. Fischer, Filippo Buttignol, Andreas Brenig

и другие.

Catalysis Today, Год журнала: 2023, Номер 429, С. 114503 - 114503

Опубликована: Дек. 28, 2023

Cu- and Fe-exchanged zeolites have been widely investigated for their applicability in selective partial oxidation of CH4 abatement environmentally harmful nitrogen oxides. However, the differentiation between spectator active sites is cumbersome due to dynamic co-existence, which aggravates elucidation redox dynamics latter. Therefore, correlated multi-spectroscopic approaches carried out under operando conditions are needed order disentangle inherent reactivity specific species. Here we describe conceptualization complementary spectroscopic methods investigation ion-exchanged employed reactions. The potential versatility this approach demonstrated by means two exemplary case studies. First, present insight generated custom ultraviolet-visible electron paramagnetic resonance spectroscopy setups operating batch mode into CH4-to-CH3OH conversion over Cu-exchanged mordenite. In addition recording method-dependent fingerprints distinct Cu centers, overall consumption simultaneously monitored both setups. extracted apparent activation energies reactive centers obtained from systems good agreement with each other allowing link bulk intrinsic site-specific kinetics all centers. Second, EPR setup equipped a flow reactor designed carry modulated excitation experiments phase-sensitive detection improve signal-to-noise ratio time resolution. cell study NO via catalytic reduction ferrierite. combination X-ray absorption spectroscopy, small portion Fe species consisting monomers gamma-positions oligomeric structures located main channel identified, kept state relevant reaction thus sustain chemical transformation NO.

Язык: Английский

Competition between Mononuclear and Binuclear Copper Sites across Different Zeolite Topologies DOI Creative Commons
Asanka Wijerathne,

Allison M. Sawyer,

Rohil Daya

и другие.

JACS Au, Год журнала: 2024, Номер 4(1), С. 197 - 215

Опубликована: Янв. 4, 2024

A key challenge for metal-exchanged zeolites is the determination of metal cation speciation and nuclearity under synthesis reaction conditions. Copper-exchanged zeolites, which are widely used in automotive emissions control potential catalysts partial methane oxidation, have particular evidenced a wide variety Cu structures that observed to change with exposure conditions, zeolite composition, topology. Here, we develop predictive models CHA, MOR, BEA, AFX, FER topologies using interatomic potentials, quantum chemical calculations, Monte Carlo simulations interrogate this vast configurational compositional space. Model predictions rationalize experimentally differences between Cu-zeolites wide-body literature, including populations, structural variations, methanol per yields. Our results show both topological features commonly Al-siting biases MOR increase population binuclear sites, explaining small mononuclear sites these materials relative other such as CHA BEA. Finally, machine learning classification model determine preference form or at different Al configurations 200 international database. reveal several extreme ends vs spectrum, highlighting synthetic options realization strong preferences.

Язык: Английский

Процитировано

20
A review on the active sites for direct oxidation of methane to methanol by copper-zeolites: Coordination structure, formation and activity DOI

Hailong Zhang,

Jiwei Li, Diandian Wang

и другие.

Coordination Chemistry Reviews, Год журнала: 2024, Номер 503, С. 215637 - 215637

Опубликована: Янв. 10, 2024

Язык: Английский

Процитировано

10
Selective Oxidative Dehydrogenation of Ethane and Propane over Copper‐Containing Mordenite: Insights into Reaction Mechanism and Product Protection DOI Creative Commons
Mikalai A. Artsiusheuski, René Verel, Jeroen A. van Bokhoven

и другие.

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(44)

Опубликована: Сен. 12, 2023

Copper(II)-containing mordenite (CuMOR) is capable of activation C-H bonds in C1 -C3 alkanes, albeit there are remarkable differences between the functionalization ethane and propane compared to methane. The reaction with CuMOR results formation ethylene propylene, while methane predominantly yields methanol dimethyl ether. By combining situ FTIR MAS NMR spectroscopies as well time-resolved Cu K-edge X-ray absorption spectroscopy, mechanism was derived, which differs significantly for each alkane. propylene proceeds via oxidative dehydrogenation corresponding alkanes selectivity above 95 % 85 propane. stable π-complexes olefins CuI sites, formed upon reduction CuII -oxo species, protects from further oxidation and/or oligomerization. This different methane, hydroxylation leading surface methoxy species bonded zeolite framework. Our findings constitute one major steps direct conversion important commodities open a novel research direction aiming at selective synthesis olefins.

Язык: Английский

Процитировано

19
Noble metal modified copper-exchanged mordenite zeolite (Cu-ex-MOR) catalysts for catalyzing the methane efficient gas-phase synthesis methanol DOI

Xuanlan Xie,

Chang Li,

Zhiheng Lu

и другие.

Energy, Год журнала: 2024, Номер 300, С. 131595 - 131595

Опубликована: Май 8, 2024

Язык: Английский

Процитировано

7
Structural Evolution of Copper-Oxo Sites in Zeolites upon the Reaction with Methane Investigated by Means of Cu K-edge X-ray Absorption Spectroscopy DOI
Mikalai A. Artsiusheuski, Оlga V. Safonova, Dennis Palagin

и другие.

The Journal of Physical Chemistry C, Год журнала: 2023, Номер 127(20), С. 9603 - 9615

Опубликована: Май 12, 2023

The structure of copper sites formed under an oxidative environment and their evolution in the course reaction with methane at elevated temperature was investigated by means Cu K-edge X-ray absorption spectroscopy for a series copper-containing MFI, MOR, FAU zeolites. pretreatment oxygen 723 K leads to formation copper(II)-oxo sites, whose nature depends on framework type. Dimeric species are CuMFI material, dimeric monomeric coexist CuMOR, agglomerated copper-oxo nanoclusters found large-pore faujasite (CuFAU). For all studied materials, resulted exclusive copper(I) species; no metallic detected even 748 K. is governed corresponding copper(II) centers. In particular, hosted CuMOR transformed into isolated cations coordinated ion-exchange positions zeolite. Contrarily, clusters present CuFAU undergo restructuring only partial loss extra-framework form aggregated similar that bulk oxide.

Язык: Английский

Процитировано

14
Redox and Kinetic Properties of Composition‐Dependent Active Sites in Copper‐Exchanged Chabazite for Direct Methane‐to‐Methanol Oxidation DOI Creative Commons
Andreas Brenig, Jörg W. A. Fischer, Daniel Klose

и другие.

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(45)

Опубликована: Июль 26, 2024

The CH

Язык: Английский

Процитировано

6
Mechanism of Hydrocarbon Formation in Methane and Methanol Conversion over Copper-Containing Mordenite DOI
Mikalai A. Artsiusheuski, René Verel, Jeroen A. van Bokhoven

и другие.

ACS Catalysis, Год журнала: 2023, Номер 13(9), С. 5864 - 5875

Опубликована: Апрель 14, 2023

Methane conversion over copper-containing zeolites can lead to the formation of C–C bonds, yielding hydrocarbons. By employing in situ MAS NMR spectroscopy, we elucidated pathways transformation methane and its partial oxidation coupling products mordenite. Below 773 K, direct is not possible, while methanol, methoxy species, dimethyl ether takes place via methanol-to-hydrocarbons (MTH) process. In presence carbon monoxide, surface acetate species are formed from methanol Koch carbonylation reaction. The nature hydrocarbon pool concomitantly hydrocarbons strongly affected by reactants: pure leads methyl-substituted cyclopentenyl cations, monoxide results benzenes. study clarifies mechanism bond during mordenite provides insights into MTH

Язык: Английский

Процитировано

12
CH3 radical-mediated direct methane to methanol conversion over CuO supported on rutile oxides DOI

Huixian Liu,

Yuyao Qin, Liwen Li

и другие.

Journal of Catalysis, Год журнала: 2024, Номер 431, С. 115388 - 115388

Опубликована: Фев. 21, 2024

Язык: Английский

Процитировано

5
Copper–oxygen adducts: new trends in characterization and properties towards C–H activation DOI Creative Commons
Jonathan De Tovar, Rébecca Leblay, Yongxing Wang

и другие.

Chemical Science, Год журнала: 2024, Номер 15(27), С. 10308 - 10349

Опубликована: Янв. 1, 2024

Recent progresses in Cu–oxygen adducts towards recalcitrant C–H activation are reviewed with focus on Cu metalloenzymes and bioinspired synthetic models, mono- to polynuclear complexes, working under homogeneous heterogeneous catalytic conditions.

Язык: Английский

Процитировано

5
Understanding C–H activation in light alkanes over Cu-MOR zeolites by coupling advanced spectroscopy and temperature-programmed reduction experiments DOI Creative Commons
Karoline Kvande,

Beatrice Garetto,

Gabriele Deplano

и другие.

Chemical Science, Год журнала: 2023, Номер 14(36), С. 9704 - 9723

Опубликована: Янв. 1, 2023

Temperature-programmed-reduction studies combined with advanced spectroscopy and data analysis methods shed light into the dynamic changes of Cu-speciation during alkane selective oxidation over Cu-mordenite zeolites.

Язык: Английский

Процитировано

10