Transition metal-doped TiO2 nanowire catalysts for the oxidative coupling of methane

Yunarti, Rika Tri; Lee, Maro; Hwang, Yoon Jeong; Choi, Jae Wook; Suh, Dong Jin; Lee, Jinwon; Kim, Il Won; Ha, Jeong Myeong

doi:10.1016/j.catcom.2014.02.026

Cited by 46 publications

(16 citation statements)

References 31 publications

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“…TiO 2 -supported vanadium oxides are extensively studied as effective and selective catalysts of organic compounds conversion [17][18][19]. For example V-doped TiO 2 was studied as catalysts for selective oxidation of ethanol [20], degradation of aldehyde [21] or photo-oxidation of methane in air [22]. Moreover, V 2 O 5 -TiO 2 oxide system is used as catalysts for the selective reduction of NO x to N 2 by ammonia in flue gases emitted by power station and diesel cars [23].…”

Section: Introductionmentioning

confidence: 99%

Titanium dioxide doped with vanadium as effective catalyst for selective oxidation of diphenyl sulfide to diphenyl sulfonate

Radko

Kowalczyk

Bidzińska

et al. 2018

J Therm Anal Calorim

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Diphenyl sulfide was oxidized to sulfoxide and sulfone over V-doped TiO 2 using a 30% solution of H 2 O 2 . The TiO 2 samples with different intended content of vanadium (0.02, 0.05, 0.1 and 0.18 mass%) were prepared by incipient wetness impregnation. Physicochemical properties of the V-doped TiO 2 were characterized by chemical analysis (ICP-OES), X-ray diffraction (XRD/in situ HT-XRD), UV-Vis diffuse reflectance spectrometry (UV-Vis DRS), N 2 -sorption measurements, electron paramagnetic resonance and cyclic voltammetry. Both vanadium oxide loading and calcination temperature influenced the structure of the V-TiO 2 samples. Vanadium species deposited on TiO 2 decreased temperatures required for anatase to rutile phase transformation. The V-TiO 2 samples were found to be efficient catalysts for oxidation of sulfides to sulfones. The sample with the lowest vanadium content (0.02VTiO 2 ) presented among the studied catalysts the best catalytic properties with respect to high conversion of diphenyl sulfide to diphenyl sulfonate. An increase in vanadium loading resulted in decrease in catalytic activity of the samples. Also non-modified TiO 2 presented significantly lower catalytic activity in comparison with 0.02VTiO 2 . This interesting effect was related to the formation of highly dispersed vanadium species catalytically active in Ph 2 S oxidation in the case of the samples with lower V-content. An increase in vanadium loading results in the formation of more aggregated V-species inactive, or less active, in the process of diphenyl sulfide oxidation.

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Section: Introductionmentioning

confidence: 99%

Titanium dioxide doped with vanadium as effective catalyst for selective oxidation of diphenyl sulfide to diphenyl sulfonate

Radko

Kowalczyk

Bidzińska

et al. 2018

J Therm Anal Calorim

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“…In the past several years, some potential catalysts have been reported, including MnOx modified with different types of co-catalysts, supports and promotors, such as oxides of Mg, Na, and Ce. However, the C2+ yields and C2+ selectivities were quite low at approximately <16% and 25-78%, respectively [4][5][6][7][8]. Additionally, coke formation was found during the reaction, resulting in catalyst deactivation.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Light Hydrocarbons via Oxidative Coupling of Methane over Silica-supported Na2WO4-TiO2 Catalyst

Seubsai¹,

Tiencharoenwong²,

Kidamorn³

et al. 2019

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Methane is of great interest for conversion into high-value hydrocarbons (C2+) and olefins, via oxidative coupling of methane (OCM) using catalysts. In this work, Na2WO4-TiO2/SiO2 catalyst, along with the single catalysts of its components (Na2WO4/SiO2 and TiO2/SiO2), was investigated for OCM reaction to C2+. We found that 5 wt% Na2WO4+ 5 wt% TiO2 on the SiO2 support was a superior catalyst for OCM reaction compared to the single catalysts. The maximum C2+ formation of the Na2WO4-TiO2/SiO2 catalyst was found under test conditions of a N2/(4CH4:1O2) feed gas ratio of 1:1, a reactor temperature of 700 ºC, and gas hourly space velocity of 9,500 h −1 , exhibiting 71.7% C2+ selectivity, 6.8% CH4 conversion, and 4.9% C2+ yield. Moreover, the activity of the catalyst had good stability over 24 h of on-stream testing. The characterizations of the Na2WO4-TiO2/SiO2 catalyst using XRD, FT-IR, XPS, FE-SEM, and TEM revealed that a crystalline structure of α-cristobalite of SiO2 was present along with TiO2 crystals, substantially enhancing the activity of the catalyst for OCM reaction to C2+.

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“…Since the production of paraffins and olefins by coupling methane molecules was suggested using Li/MgO 29,30 and other metals oxides, 31,32 La 2 O 3 , 33 Sm 2 O 3 , 34–36 modified SrTiO 3 , modified BaTiO 3 , modified LaAlO 3 , 37–39 and PbO/MgO 40 have been investigated as potential catalysts. Nanostructured catalysts, including La 2 O 3 ‐CeO 2 nanofibers, 41 CeO 2 /ZnO, 42 Sm 2 O 3 nanoparticles, 43 core‐shell particles, 44 and metal‐doped TiO 2 nanorods 45 have also been suggested, although such nanostructures may undergo degradation under the high OCM reaction temperatures. Na 2 WO 4 /Mn/SiO 2 (NWM) has been suggested as a highly active and stable OCM catalyst 46–48 ; however, the origin of the high activity remains unclear 48,49 .…”

Section: Introductionmentioning

confidence: 99%

Upgrading of sulfur‐containing biogas into high quality fuel via oxidative coupling of methane

Choi

Suh

et al. 2021

Int J Energy Res

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Summary Biogas, which contains methane (CH4), carbon dioxide (CO2), hydrogen sulfide (H2S), and other minor compounds, is a promising energy source and chemical feedstock (not least because it is generated from waste); however, its application as fuel is limited because of its low calorific value, which can be mitigated by upgrading biogas to high‐quality fuels via the oxidative coupling of methane (OCM), a catalytic process that increases its higher heating value from 39.9 (CH4, Wobbe index = 53.5 MJ/Nm3) to 41.7 MJ/Nm3 (OCM product mixture, Wobbe index = 54.4 MJ/Nm3), thus achieving compliance with the fuel standards in many countries (Wobbe index = 45.5‐55.0 MJ/Nm3). Among the compounds produced during OCM, H2S is formed in minor amounts but strongly suppresses biogas valorization, mainly because of potential catalyst poisoning. To understand the effects of sulfur compounds on OCM catalysts, three such catalysts, namely perovskites (SrTiO3 and LaAlO3) and Na2WO4/Mn/SiO2 (NWM), were used to convert biogas into olefins and paraffins. The oxidation of H2S in biogas produced sulfur dioxide, which did not strongly affect NWM but was strongly adsorbed by perovskites and, in turn, significantly reduced their OCM activity. Furthermore, long‐term (100 hours) stability testing demonstrated that the OCM activity of NWM was stable in the presence of H2S. Consequently, the influence of sulfur compounds on the catalysts during the OCM process was elucidated, including catalyst poisoning via sulfur species adsorption. The strategy to suppress the detrimental effects of sulfur poisoning was suggested, which can contribute to the development of feasible process for valorizing biogas to high quality fuels and chemicals.

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Transition metal-doped TiO2 nanowire catalysts for the oxidative coupling of methane

Cited by 46 publications

References 31 publications

Titanium dioxide doped with vanadium as effective catalyst for selective oxidation of diphenyl sulfide to diphenyl sulfonate

Titanium dioxide doped with vanadium as effective catalyst for selective oxidation of diphenyl sulfide to diphenyl sulfonate

Synthesis of Light Hydrocarbons via Oxidative Coupling of Methane over Silica-supported Na2WO4-TiO2 Catalyst

Upgrading of sulfur‐containing biogas into high quality fuel via oxidative coupling of methane

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