Copper-Modified Zeolites and Silica for Conversion of Methane to Methanol

Powder materials containing copper ions supported on ZSM-5 (Cu-Zeolite Socony Mobil-5) and SSZ-13 (Cu-Standard Oil synthesised zeolite-13), and predominantly CuO nanoparticles on amorphous SiO 2 were synthesised, characterised, wash-coated onto ceramic monoliths and, for the first time, compared as catalysts for direct conversion of methane to methanol (DCMM) at ambient pressure (1 atm) using O 2 , N 2 O and NO as oxidants. Methanol production was monitored and quantified using Fourier transform infrared spectroscopy. Methanol is formed over all monolith samples, though the formation is considerably higher for the copper-exchanged zeolites. Hence, copper ions are the main active sites for DCMM. The minor amount of methanol produced over the Cu/SiO 2 sample, however, suggests that zeolites are not the sole substrate that can host those active copper sites but also silica. Further, we present the first ambient pressure in situ infrared spectroscopic measurements revealing the formation and consumption of surface methoxy species, which are considered to be key intermediates in the DCMM reaction.

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XPS AND FTIR STUDIES OF Mo/ZSM-5 CATALYSTS FOR NONOXIDATIVE CONVERSION OF METHANE TO AROMATICS

Surface Review and Letters ◽

10.1142/s0218625x0100152x ◽

2001 ◽

Vol 08 (06) ◽

pp. 627-632 ◽

Cited By ~ 3

Author(s):

H. Y. CHEN ◽

S. TANG ◽

Z. Y. ZHONG ◽

J. LIN ◽

K. L. TAN

Keyword(s):

Methane Conversion ◽

Active Sites ◽

Reaction Times ◽

Initial Reaction ◽

Oxygen Treatment ◽

Conversion Of Methane ◽

Xps Study ◽

Nonoxidative Conversion ◽

First Time

In this investigation, several Mo/ZSM-5 catalysts with various Mo loadings and various reaction times were prepared, and methane conversion to aromatics without the presence of oxygen was studied by microreactor evaluation, FTIR and XPS. It was found, for the first time, that oxygen treatment before the reaction could shorten the induction period of this reaction. In situ FTIR study indicated the formation of [Formula: see text] species ( 888 cm -1) and O–Al ( 670 cm -1) on the surface of the catalyst as a result of the oxygen treatment. The two IR bands shifted to 854 and 659 cm -1 respectively when 18 O 2 was used. These oxygen species may take part in the initial reaction and shorten the induction time. The XPS study revealed the coexistence of Mo 2 C and MoO 3 species on working catalyst surfaces, and a proper Mo 2 C/MoO 3 ratio (~0.38) was identified for the best aromatization Mo/ZSM-5 catalyst. The active sites for methane conversion to aromatics should include Mo oxide as well as Mo carbide.

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Catalytic and Noncatalytic Conversion of Methane to Olefins and Synthesis Gas in an AC Parallel Plate Discharge Reactor

Journal of Chemistry ◽

10.1155/2013/676901 ◽

2013 ◽

Vol 2013 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Mohammad Ali Khodagholi ◽

Mohammad Irani

Keyword(s):

Synthesis Gas ◽

Parallel Plate ◽

Discharge Plasma ◽

Ambient Pressure ◽

Direct Conversion ◽

Gas Discharge ◽

Input Power ◽

Outer Diameter ◽

Gas Discharge Plasma ◽

Conversion Of Methane

Direct conversion of methane to ethylene, acetylene, and synthesis gas at ambient pressure and temperature in a parallel plate discharge reactor was investigated. The experiments were carried out using a quartz reactor of outer diameter of 9 millimeter and a driving force of ac current of 50 Hz. The input power to the reactor to establish a stable gas discharge varied from 9.6 to maximum 15.3 watts (w). The effects of ZSM5, Fe–ZSM5, and Ni–ZSM5 catalysts combined with corona discharge for conversion of methane to more valued products have been addressed. It was found that in presence or absence of a catalyst in gas discharge reactor, the rate of methane and oxygen conversion increased upon higher input power supplied to the reactor. The effect of Fe–ZSM5 catalyst combined with gas discharge plasma yields C2hydrocarbons up to 21.9%, which is the highest productions of C2hydrocarbons in this work. The effect of combined Ni–ZSM5 and gas discharge plasma was mainly production of synthesis gas. The advantage of introducing ZSM5 to the plasma zone was increase in synthesis gas and acetylene production. The highest energy efficiency was 0.22 mmol/kJ, which belongs to lower rate of energy injection to the reactor.

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Influence of the ZrO2 Crystalline Phases on the Nature of Active Sites in PdCu/ZrO2 Catalysts for the Methanol Steam Reforming Reaction—An In Situ Spectroscopic Study

Catalysts ◽

10.3390/catal10091005 ◽

2020 ◽

Vol 10 (9) ◽

pp. 1005

Author(s):

Daniel Ruano ◽

Beatriz M. Pabón ◽

Càtia Azenha ◽

Cecilia Mateos-Pedrero ◽

Adélio Mendes ◽

...

Keyword(s):

Steam Reforming ◽

Active Sites ◽

Surface Composition ◽

Ambient Pressure ◽

Chemical Properties ◽

Spectroscopic Studies ◽

Metal Species ◽

Methanol Steam Reforming ◽

Reaction Products

In this work, the electronic properties of the metal sites in cubic and monoclinic ZrO2 supported Pd and PdCu catalysts have been investigated using CO as probe molecule in in-situ IR studies, and the surface composition of the outermost layers has been studied by APXPS (Ambient Pressure X-ray Photoemission Spectroscopy). The reaction products were followed by mass spectrometry, making it possible to relate the chemical properties of the catalysts under reaction conditions with their selectivity. Combining these techniques, it has been shown that the structure of the support (monoclinic or cubic ZrO2) affects the metal dispersion, mobility, and reorganization of metal sites under methanol steam reforming (MSR) conditions, influencing the oxidation state of surface metal species, with important consequences in the catalytic activity. Correlating the mass spectra of the reaction products with these spectroscopic studies, it was possible to conclude that electropositive metal species play an imperative role for high CO2 and H2 selectivity in the MSR reaction (less CO formation).

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Direct conversion of methane into oxygenates by H2O2 generated in situ from dihydrogen and dioxygen

Catalysis Communications ◽

10.1016/s1566-7367(01)00030-9 ◽

2001 ◽

Vol 2 (6-7) ◽

pp. 187-190 ◽

Cited By ~ 33

Author(s):

E.D Park ◽

Y.-S Hwang ◽

J.S Lee

Keyword(s):

Direct Conversion ◽

Conversion Of Methane

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METHANE LIQUEFACTION: Selective Conversion of Methane to Cyclohexane via Efficient Surface-Hydrogen-Transfer Catalyzed by GaN-Supported Platinum Clusters

10.21203/rs.3.rs-1132273/v1 ◽

2021 ◽

Author(s):

Li-Da Tan ◽

Hui Su ◽

Jingtan Han ◽

Mingxin Li ◽

Chao-Jun Li

Keyword(s):

Hydrogen Transfer ◽

Ambient Pressure ◽

Chemical Research ◽

Methane Aromatization ◽

Surface Hydrogen ◽

Platinum Cluster ◽

Supported Platinum ◽

Conversion Of Methane ◽

Platinum Clusters

Abstract Non-oxidative liquefaction of methane at room temperature and ambient pressure has long been a scientific “holy grail” of chemical research. In this report, we exploit an unprecedented catalytic transformation of methane exclusively to cyclohexane through effective surface-hydrogen-transfer (SHT) at the heterojunctions boundary consisting of electron-rich platinum cluster (Pt) loaded on methane-activating gallium nitride (GaN) host. The experimental analysis demonstrates that interface-induced overall reaction starts with methane aromatization to benzene initiated by the Ga-N pairs, followed by hydrogenation of benzene to cyclohexane via hydrogen transfer. The in-situ activated hydrogen at electron-rich metal Pt cluster plays a key role for the hydrogenation and enables an outstanding selectivity (as high as 89 %) towards cyclohexane, which is well-delivered even after 5 recycling runs.

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In situ formation of the active sites in Pd–Au bimetallic nanocatalysts for CO oxidation: NAP (near ambient pressure) XPS and MS study

Faraday Discussions ◽

10.1039/c7fd00219j ◽

2018 ◽

Vol 208 ◽

pp. 255-268 ◽

Cited By ~ 19

Author(s):

A. V. Bukhtiyarov ◽

I. P. Prosvirin ◽

A. A. Saraev ◽

A. Yu. Klyushin ◽

A. Knop-Gericke ◽

...

Keyword(s):

Co Oxidation ◽

Surface Structure ◽

Active Sites ◽

Ambient Pressure ◽

Ambient Pressure Xps ◽

P Transformation ◽

In Situ Formation ◽

Bimetallic Nanocatalysts ◽

Near Ambient Pressure Xps

Transformation of the surface structure of HOPG-supported bimetallic Pd–Au particles in the course of CO oxidation has been demonstrated using NAP XPS and MS techniques.

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Direct Evidence of Cobalt Oxyhydroxide Formation on a La0.2Sr0.8CoO3 Perovskite Water Splitting Catalyst

10.21203/rs.3.rs-289935/v1 ◽

2021 ◽

Author(s):

Anthony Boucly ◽

Luca Artiglia ◽

Emiliana Fabbri ◽

Dennis Palagin ◽

Dino Aergerter ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Active Sites ◽

Direct Evidence ◽

Ambient Pressure ◽

Spectral Feature ◽

Ex Situ ◽

Oxide Surface ◽

Catalytic Systems ◽

Cobalt Oxyhydroxide

Abstract Understanding the mechanism of oxygen evolution reaction (OER) on perovskite materials is of great interest to tailor the synthesis of better catalyst materials. Despite the huge amount of literature reports, the complexity of catalytic systems and scarce in situ and operando surface sensitive spectroscopic tools render the detection of active sites and the understanding of the reaction mechanisms challenging. Here, we carried out and compared in situ and ex situ ambient pressure X-ray photoelectron spectroscopy experimental procedures on a La0.2Sr0.8CoO3 perovskite OER catalyst. Experimental results show that segregated surface strontium, which is present in the as prepared sample, is leached into the electrolyte after immersion, leading to surface cobalt active sites enrichment. Such cobalt-enriched oxide surface evolves into a new phase, whose spectral feature is detected in situ, during/after OER. With the help of theoretical simulations, such species is assigned to cobalt oxyhydroxide, providing a direct evidence of its crucial role in the reaction.

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Hydrophobic zeolite modification for in situ peroxide formation in methane oxidation to methanol

Science ◽

10.1126/science.aaw1108 ◽

2020 ◽

Vol 367 (6474) ◽

pp. 193-197 ◽

Cited By ~ 5

Author(s):

Zhu Jin ◽

Liang Wang ◽

Erik Zuidema ◽

Kartick Mondal ◽

Ming Zhang ◽

...

Keyword(s):

Methane Oxidation ◽

Active Sites ◽

Catalyst System ◽

Oxidation Of Methane ◽

Conversion Of Methane ◽

Low Efficiency ◽

Mild Temperature ◽

Diffusion Of Hydrogen ◽

Zeolite Modification

Selective partial oxidation of methane to methanol suffers from low efficiency. Here, we report a heterogeneous catalyst system for enhanced methanol productivity in methane oxidation by in situ generated hydrogen peroxide at mild temperature (70°C). The catalyst was synthesized by fixation of AuPd alloy nanoparticles within aluminosilicate zeolite crystals, followed by modification of the external surface of the zeolite with organosilanes. The silanes appear to allow diffusion of hydrogen, oxygen, and methane to the catalyst active sites, while confining the generated peroxide there to enhance its reaction probability. At 17.3% conversion of methane, methanol selectivity reached 92%, corresponding to methanol productivity up to 91.6 millimoles per gram of AuPd per hour.

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Effects of single and double active sites of Cu oxide clusters over MFI zeolite for direct conversion of methane to methanol: DFT calculations

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05435f ◽

2021 ◽

Author(s):

Watinee Nunthakitgoson ◽

Anawat Thivasasith ◽

Thana Maihom ◽

Chularat Wattanakit

Keyword(s):

Dft Calculations ◽

Active Sites ◽

Direct Conversion ◽

Mfi Zeolite ◽

Zeolite Framework ◽

Conversion Of Methane

In this context, we investigate the effect of the single and double active sites of Cu oxide clusters over the MFI zeolite framework for direct conversion of methane to methanol....

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