Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation DOI Creative Commons
Qingpeng Cheng, Guanna Li,

Xueli Yao

et al.

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

Iron and Copper Active Sites in Zeolites and Their Correlation to Metalloenzymes DOI
Benjamin E. R. Snyder, Max L. Bols, Robert A. Schoonheydt

et al.

Chemical Reviews, Journal Year: 2017, Volume and Issue: 118(5), P. 2718 - 2768

Published: Dec. 19, 2017

Metal-exchanged zeolites are a class of heterogeneous catalysts that perform important functions ranging from selective hydrocarbon oxidation to remediation NOx pollutants. Among these, copper and iron remarkably reactive, hydroxylating methane benzene selectively at low temperature form methanol phenol, respectively. In these systems, reactivity occurs well-defined molecular transition metal active sites, in this review we discuss recent advances the spectroscopic characterization sites their reactive intermediates. Site-selective spectroscopy continues play key role, making it possible focus on exist within distribution inactive spectator centers. The definition geometric electronic structures metallozeolites has advanced level bioinorganic chemistry, enabling direct comparison metallozeolite functionally analogous Fe Cu biology. We identify significant parallels differences strategies used by each achieve high reactivity, highlighting potentially interesting mechanisms tune performance synthetic catalysts.

Language: Английский

Citations

319
Advances in methane conversion processes DOI Creative Commons
Bingwen Wang,

Sandra C. Albarracín-Suazo,

Yomaira J. Pagán‐Torres

et al.

Catalysis Today, Journal Year: 2017, Volume and Issue: 285, P. 147 - 158

Published: Feb. 14, 2017

Language: Английский

Citations

258
Stability and reactivity of copper oxo-clusters in ZSM-5 zeolite for selective methane oxidation to methanol DOI
Guanna Li,

Peter Vassilev,

Maricruz Sanchez‐Sanchez

et al.

Journal of Catalysis, Journal Year: 2016, Volume and Issue: 338, P. 305 - 312

Published: April 4, 2016

Language: Английский

Citations

240
Methane conversion into different hydrocarbons or oxygenates: current status and future perspectives in catalyst development and reactor operation DOI
Evgenii V. Kondratenko, Tim Peppel,

Dominik Seeburg

et al.

Catalysis Science & Technology, Journal Year: 2016, Volume and Issue: 7(2), P. 366 - 381

Published: Dec. 13, 2016

This Perspective highlights recent developments in methane conversion into different hydrocarbons and C1-oxygenates. Our analysis identified possible directions for further research to bring the above approaches a commercial level.

Language: Английский

Citations

237
Formation of [Cu2O2]2+ and [Cu2O]2+ toward C–H Bond Activation in Cu-SSZ-13 and Cu-SSZ-39 DOI
Bahar Ipek,

Matthew J. Wulfers,

Hacksung Kim

et al.

ACS Catalysis, Journal Year: 2017, Volume and Issue: 7(7), P. 4291 - 4303

Published: May 18, 2017

Cu-exchanged small-pore zeolites (CHA and AEI) form methanol from methane (>95% selectivity) using a 3-step cyclic procedure (Wulfers et al. Chem. Commun. 2015, 51, 4447−4450) with amounts higher than Cu-ZSM-5 Cu-mordenite on per gram Cu basis. Here, the CuxOy species formed Cu-SSZ-13 Cu-SSZ-39 following O2 or He activation at 450 °C are identified as trans-μ-1,2-peroxo dicopper(II) ([Cu2O2]2+) mono-(μ-oxo) ([Cu2O]2+) synchrotron X-ray diffraction, in situ UV–vis, Raman spectroscopy theory. [Cu2O2]2+ [Cu2O]2+ showed ligand-to-metal charge transfer (LMCT) energies between 22,200 35,000 cm–1, Cu–O vibrations 360, 510, 580, 617 cm–1 an O–O vibration 837 cm–1. The assigned to species, whereas (Δ18O = 24 cm–1) is stretching of thermodynamically favored Cu–O–Cu angle 95°. On basis intensity loss broad LMCT band 571 upon reaction, both suggested take part 200 core playing dominant role. A relationship [Cu2Oy]2+ concentration Cu(II) eight-membered ring observed related [CuOH]+ intermediate formation.

Language: Английский

Citations

225
Active sites and mechanisms in the direct conversion of methane to methanol using Cu in zeolitic hosts: a critical examination DOI Creative Commons
Mark A. Newton,

Amy J. Knorpp,

Vitaly L. Sushkevich

et al.

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(5), P. 1449 - 1486

Published: Jan. 1, 2020

In this critical review we examine the current state of our knowledge in respect nature active sites copper containing zeolites for selective conversion methane to methanol. We consider varied experimental evidence arising from application X-ray diffraction, and vibrational, electronic, spectroscopies that exist, along with results theory. aim establish both what is known regarding these elusive materials how they function, also where gaps still offer suggestions strategies as might be closed such rational design more effective efficient type proceed further.

Language: Английский

Citations

221
The Nuclearity of the Active Site for Methane to Methanol Conversion in Cu-Mordenite: A Quantitative Assessment DOI
Dimitrios K. Pappas, Andrea Martini, Michael Dyballa

et al.

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(45), P. 15270 - 15278

Published: Oct. 22, 2018

The direct conversion of methane to methanol (MTM) is a reaction that has the potential disrupt great part synthesis gas-derived chemical industry. However, despite many decades research, active enough catalysts and suitable processes for industrial application are still not available. Recently, several copper-exchanged zeolites have shown considerable activity selectivity in MTM reaction. Understanding nature site these materials essential any further development field. Herein, we apply multivariate curve resolution analysis X-ray absorption spectroscopy data accurately quantify fraction Cu Cu-MOR (MOR = mordenite), allowing an unambiguous determination nuclearity as dicopper site. By rationalizing compositional parameters conditions, achieve highest yield per yet reported over Cu-zeolites, 0.47 mol/mol.

Language: Английский

Citations

212
Monocopper Active Site for Partial Methane Oxidation in Cu-Exchanged 8MR Zeolites DOI
Ambarish Kulkarni, Zhi‐Jian Zhao,

Samira Siahrostami

et al.

ACS Catalysis, Journal Year: 2016, Volume and Issue: 6(10), P. 6531 - 6536

Published: Aug. 17, 2016

Direct conversion of methane to methanol using oxygen is experiencing renewed interest owing the availability new natural gas resources. Copper-exchanged zeolites such as mordenite and ZSM-5 have shown encouraging results, di- tri-copper species been suggested active sites. Recently, small eight-membered ring (8MR) including SSZ-13, -16, -39 be for oxidation, but sites reaction mechanisms in these 8MR are not known. In this work, we use density functional theory (DFT) calculations systematically evaluate monocopper partial oxidation Cu-exchanged SSZ-13. On basis kinetic thermodynamic arguments, suggest that [CuIIOH]+ responsible experimentally observed activity. Our results successfully explain available spectroscopic data experimental observations (i) necessity water extraction (ii) effect Si/Al ratio on catalyst Monocopper yet an site reaction, our may provide complementary routes activation addition known [Cu–O–Cu]2+ Cu3O3 motifs.

Language: Английский

Citations

209
Misconceptions and challenges in methane-to-methanol over transition-metal-exchanged zeolites DOI
Manoj Ravi, Vitaly L. Sushkevich,

Amy J. Knorpp

et al.

Nature Catalysis, Journal Year: 2019, Volume and Issue: 2(6), P. 485 - 494

Published: May 20, 2019

Language: Английский

Citations

181
Methane Oxidation to Methanol DOI Creative Commons
Nicholas F. Dummer, David J. Willock, Qian He

et al.

Chemical Reviews, Journal Year: 2022, Volume and Issue: 123(9), P. 6359 - 6411

Published: Dec. 2, 2022

The direct transformation of methane to methanol remains a significant challenge for operation at larger scale. Central this is the low reactivity conditions that can facilitate product recovery. This review discusses issue through examination several promising routes and an evaluation performance targets are required develop process We explore methods currently used, emergence active heterogeneous catalysts their design reaction mechanisms provide critical perspective on future operation. Initial experiments discussed where identification gas phase radical chemistry limited further development by approach. Subsequently, new class catalytic materials based natural systems such as iron or copper containing zeolites were explored milder conditions. key issues these technologies conversion often overoxidation products. Despite this, interest high in wider appeal effective route products from C–H activation, particularly with need transition net carbon zero renewable sources exciting.

Language: Английский

Citations

170