Metamorphosis-like Transformation during Activation of In/SiO2 Catalyst for Non-oxidative Coupling of Methane: In Situ X-ray Absorption Fine Structure Analysis

Kashaboina, Upendar; Nishikawa, Yoshinori; Wakisaka, Yuki; Sirisit, Natee; Nagamatsu, Shin‐ichi; Bao, Deling; Ariga-Miwa, Hiroko; Takakusagi, Satoru; Inami, Yuta; Kuriyama, Fumiya; Dipu, Arnoldus Lambertus; Ogihara, Hitoshi; Iguchi, Shoji; Yamanaka, Ichiro; Wada, Takahiro; Asakura, Kiyotaka

doi:10.1246/cl.190440

Cited by 13 publications

(15 citation statements)

References 19 publications

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“…Above discussion is based on the assumption that the surface structure is the same as the bulk terminated and the structure under the working conditions is identical to that before and after the reaction. In order to reveal the real active site structure, we are going to carry out in situ EXAFS measurements of Ni2P catalysts at 1173 K under the flow of methane like the EXAFS analysis of In/SiO 2 NOCM catalyst [19].…”

Section: Samplesmentioning

confidence: 99%

Active Phase Structure of the SiO2-supported Nickel Phosphide Catalysts for Non-oxidative Coupling of Methane (NOCM) Reactions

Rashid

Dipu

Nishikawa

et al. 2020

e-J. Surf. Sci. Nanotechnol.

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SiO 2-supported NiP binary catalysts show high activity for the non-oxidative coupling of methane (NOCM) reactions, one of the most difficult but important catalytic reactions. We have studied the SiO 2-supported NiP binary catalysts by extended X-ray absorption fine structure (EXAFS) with different Ni : P ratios. NiP binary catalyst with the composition of Ni : P = 1 : 1 was the most active among the three different compositions. EXAFS showed that the NiP catalyst with Ni : P = 1 : 1 had a Ni 2 P structure. The structure was stable after the high temperature (1173 K) NOCM reaction conditions for 12 h. It is interesting that Ni 2 P shows high catalytic activities in many other reactions such as hydrodesulfurization, hydrogen evolution reaction, and so on. It may be due to the appropriate electronic and geometrical modification of a Ni active site by P.

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Section: Samplesmentioning

confidence: 99%

Active Phase Structure of the SiO2-supported Nickel Phosphide Catalysts for Non-oxidative Coupling of Methane (NOCM) Reactions

Rashid

Dipu

Nishikawa

et al. 2020

e-J. Surf. Sci. Nanotechnol.

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“…Methane, the simplest hydrocarbon, has emerged as an attractive source of both carbon and energy because its annual production has continued to grow since the shale gas revolution that commenced in the United States in 2006. − This gaseous hydrocarbon has been consumed directly as fuel, but another important approach is to transform it into a variety of platform chemicals widely employed in the chemical industry. Methane reactions include steam/dry reforming to produce a synthesis gas (i.e., a mixture of CO and H 2 ); partial oxidation to obtain CO, methanol, and formaldehyde; halogenation to provide methyl halides; and dehydroaromatization to synthesize benzene. − ,,, Other examples are coupling reactions under oxidative/nonoxidative conditions to synthesize light paraffins and olefins directly from methane, where both reactions proceed exothermically and thus favor low reaction temperatures. − ,− ,− Under oxidative conditions, such mild reaction conditions are also beneficial for the suppression of undesired side reactions involving the complete oxidation of methane and desired hydrocarbon products to CO 2 as well as coke formation. However, the extremely high dissociation energy of the C–H bonds of methane (ca.…”

Section: Introductionmentioning

confidence: 99%

Mechanochemical Route for Preparation of MFI-Type Zeolites Containing Highly Dispersed and Small Ce Species and Catalytic Application to Low-Temperature Oxidative Coupling of Methane

Yabushita

Yoshida

Osuga

et al. 2021

Ind. Eng. Chem. Res.

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MFI-type zeolites containing Ce species were prepared by a mechanochemically assisted two-step method, where first an amorphous Si–Ce–O composite was produced via a mechanochemical reaction of SiO2 and CeO2 and then transformed into an MFI-type zeolite under hydrothermal conditions. The Ce species in this sample were more highly dispersed than those in the two control materials: a Ce-containing MFI-type zeolite synthesized via the conventional one-pot hydrothermal approach and Ce species simply deposited on silicalite-1. The highly dispersed and small Ce species in the zeolite exhibited a unique catalytic performance for the oxidative conversion of methane after the impregnation of Pd species, and the combination of Pd and Ce species produced ethane even at reaction temperatures as low as 100–300 °C.

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“…In situ XAFS technique was applied to characterize the active species for nonoxidative methane coupling reactions. 33,34 Our XAFS and TEM/EDS analyses discovered that the Ru−Sn bimetallic particles were formed during the reaction, and the bimetallic particles are the key species to achieve high selectivity. O (0.30 mmol), and 100 mL of water was stirred at 50 °C for 24 h. The obtained slurry was filtered and washed with 1 L of distilled water.…”

Section: Introductionmentioning

confidence: 97%

“…In situ XAFS tracked the changes of chemical states and structures of the bimetallic compounds under the reaction conditions. In situ XAFS technique was applied to characterize the active species for nonoxidative methane coupling reactions. , Our XAFS and TEM/EDS analyses discovered that the Ru–Sn bimetallic particles were formed during the reaction, and the bimetallic particles are the key species to achieve high selectivity.…”

Section: Introductionmentioning

confidence: 98%

In Situ Formation of Ru–Sn Bimetallic Particles for Non-Oxidative Coupling of Methane

et al. 2023

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The direct coupling of methane from natural gas and shale gas is an essential chemical process to produce C2 products which are substrates for polymers, resins, and various functional organic compounds. An appropriate catalyst is necessary to achieve high selectivity to convert methane to the target products. In this study, we investigated the ability of in situ-generated bimetallic Ru–Sn particles to catalyze the non-oxidative coupling of methane to C2 species at 500 °C and observed C2 products’ selectivity of >99% in hydrocarbons. The addition of Sn to Ru resulted in the suppression of coke formation while maintaining the conversion rate of methane to hydrocarbons. X-ray absorption fine structure analysis revealed the mechanism of the in situ formation of Ru–Sn bimetallic particles on the surface of the support. Ru(IV) is initially reduced to Ru(0) particles under methane flow at 400–500 °C. Then, Sn(IV) species around the Ru particles are reduced and dispersed on the outer surface of the Ru particles at 500 °C, although the Sn species were not reduced without Ru at 500 °C. These results point out that Sn(IV) is reduced by active hydrogen atoms generated by the reaction between Ru particles and methane molecules. Hydrogen spills over the surface and reduces the Sn(IV) species. This in situ-formed Ru–Sn bimetallic species showed good performance for non-oxidative coupling of methane.

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Metamorphosis-like Transformation during Activation of In/SiO₂ Catalyst for Non-oxidative Coupling of Methane: In Situ X-ray Absorption Fine Structure Analysis

Cited by 13 publications

References 19 publications

Active Phase Structure of the SiO<sub>2</sub>-supported Nickel Phosphide Catalysts for Non-oxidative Coupling of Methane (NOCM) Reactions

Active Phase Structure of the SiO<sub>2</sub>-supported Nickel Phosphide Catalysts for Non-oxidative Coupling of Methane (NOCM) Reactions

Mechanochemical Route for Preparation of MFI-Type Zeolites Containing Highly Dispersed and Small Ce Species and Catalytic Application to Low-Temperature Oxidative Coupling of Methane

In Situ Formation of Ru–Sn Bimetallic Particles for Non-Oxidative Coupling of Methane

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