Direct Photocatalytic Oxidation of Methane to Liquid Oxygenates with Molecular Oxygen over Nanometals/ZnO Catalysts

2020 ◽  
pp. 93-117
Author(s):  
Hui Song
Keyword(s):  
Molecular Oxygen ◽  
Photocatalytic Oxidation ◽  
Oxidation Of Methane

scholarly journals Atmospheric deuterium fractionation: HCHO and HCDO yields in the CH<sub>2</sub>DO+O<sub>2</sub> reaction

2007 ◽  
Vol 7 (4) ◽  
pp. 10019-10041 ◽  
Author(s):  
E. Nilsson ◽  
M. S. Johnson ◽  
F. Taketani ◽  
Y. Matsumi ◽  
M. D. Hurley ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Ftir Spectroscopy ◽  
Molecular Oxygen ◽  
Molecular Hydrogen ◽  
Branching Ratio ◽  
Hydrogen Atom Transfer ◽  
Photochemical Oxidation ◽  
Oxidation Of Methane ◽  
Methoxy Radical ◽  
Deuterium Enrichment

Abstract. The formation of formaldehyde via hydrogen atom transfer from the methoxy radical to molecular oxygen is a key step in the atmospheric photochemical oxidation of methane, and in the propagation of deuterium from methane to molecular hydrogen. We report the results of the first investigation of the branching ratio for HCHO and HCDO formation in the CH2DO+O2 reaction. Labeled methoxy radicals (CH2DO) were generated in a photochemical reactor by photolysis of CH2DONO. HCHO and HCDO concentrations were measured using FTIR spectroscopy. Significant deuterium enrichment was seen in the formaldehyde product, from which we derive a branching ratio of 88.2±1.1% for HCDO and 11.8±1.1% for HCHO. The implications of this fractionation on the propagation of deuterium in the atmosphere are discussed.

Solar Photocatalytic Oxidation of Methane to Methanol with Water over RuOx/ZnO/CeO2 Nanorods

2021 ◽  
Author(s):  
Dan Yu ◽  
Yanyan Jia ◽  
Zhou Yang ◽  
Hongwen Zhang ◽  
Jiwu Zhao ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Oxidation Of Methane

scholarly journals Laboratory-scale photomineralisation of n-alkanes in aqueous solution, by photocatalytic membranes immobilising titanium dioxide

2005 ◽  
Vol 7 (2) ◽  
pp. 79-85 ◽  
Author(s):  
Ignazio Renato Bellobono ◽  
Franca Morazzoni ◽  
Riccardo Bianchi ◽  
Emilia Simona Mangone ◽  
Rodica Stanescu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Oxidation ◽  
Point Of View ◽  
Laboratory Scale ◽  
Kinetic Constants ◽  
Quantum Yields ◽  
Oxidation Of Methane ◽  
Oxygen Donor ◽  
Absorbed Power ◽  
Kinetics Of

Kinetics of photocatalytic oxidation of methane, ethane,n-heptane,n-decane, andn-dodecane, to yield intermediates, and photomineralisation of intermediates, to yield carbon dioxide and water, was studied in aqueous solution, by a laboratory-scale photoreactor and photocatalytic membranes immobilizing30±3wt.% ofTiO2, in the presence of stoichiometric hydrogen peroxide as oxygen donor. The whole volume of irradiated solution was4.000±0.005L, the ratio between this volume and the geometrical apparent surface of the irradiated side of the photocatalytic membrane was3.8±0.1cm, and the absorbed power 0.30W/cm (cylindrical geometry). A kinetic model was used, by which mineralisation of substrate toCO2was supposed to occur, by kinetic constantsk1, through one single intermediate, mediating the behaviour of all the numerous real intermediates formed in the path from the substrate toCO2(kinetic constants of formation of the latter beingk2). A competitive Langmuirian adsorption of both substrate and “intermediate” was also supposed to be operative, as expressed by apparent adsorption constantsk1andk2, possessing a, partly at least, kinetic significance. By Langmuir-Hinshelwood treatment of initial rate data, starting values of thekandKcouples were obtained, from which, by a set of differential equations, the final optimised parameters,k1andk1,k2andK2, were calculated, able fit the whole photomineralisation curve, and not only its initial segment, as the Langmuirian parameters do. The parameters of present work are critically compared with those obtained in two preceding set of studies relative ton-alkanoic acids and ton-alkanols. They are interpreted on the basis of a closer behaviour of hydrocarbons to alkanols, from the photocatalytic point of view, than to carboxylic acids are. Discussion of limiting effective quantum yields, and their comparison with maximum, theoretical values, are also carried out.

Study on the Photo-Electro-Catalytic Oxidation of Methane

2013 ◽  
Vol 864-867 ◽  
pp. 1421-1426
Author(s):  
Wen Yan Wu ◽  
Luo Chun Wang ◽  
Zhen Zhou ◽  
Ke Jia Liu ◽  
Xiao Hua Li ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Photocatalytic Oxidation ◽  
Uv Light ◽  
Ambient Pressure ◽  
Kinetic Constant ◽  
Illumination Time ◽  
Oxidation Of Methane ◽  
Conversion Of Methane ◽  
Intermittent Illumination ◽  
Electro Catalytic Oxidation

Emission control of methane from landfills has received considerable attentions in recent years. Photo-electro-catalytic oxidation of methane was carried out at the mode of continuous electrolysis and intermittent illumination with TiO2-coated titanium mesh plate as pholocatalyst and electrode in combination with ionic liquid as electrolyte under UV light irradiation. The result showed that the rapid conversion of methane was achieved under ambient pressure and temperature through photocatalytic oxidation combining with electrolysis. Under the mode of intermittent illumination (on:off = 10 min : 10 min) and continuous electrolysis (II-CE), the highest oxidation rate of methane (280 mg/(m3min)) was obtained. Under fixed off time and total illumination time, the oxidation quantity of methane linearly increased with the intermittent frequency. Photo-electro-catalytic oxidation of methane can be described by the first-order kinetics, and the apparent kinetic constant increased with the intermittent frequency.

Photocatalytic Oxidation of Toluene to Benzaldehyde by Molecular Oxygen

1996 ◽  
Vol 100 (10) ◽  
pp. 4219-4223 ◽  
Author(s):  
Yun Mao ◽  
Andreja Bakac
Keyword(s):  
Molecular Oxygen ◽  
Photocatalytic Oxidation
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