首页|Low-temperature catalytic methane deep oxidation over sol-gel derived mesoporous hausmannite(Mn3O4)spherical particles

Low-temperature catalytic methane deep oxidation over sol-gel derived mesoporous hausmannite(Mn3O4)spherical particles

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In this study,Mn3O4 spherical particles(SPs)were synthesized by the sol-gel process,after which they were thermally annealed at 400 ℃,and comprehensively characterized.X-ray Diffraction(XRD)revealed that Mn3O4 exhibited a tetragonal spinel structure,and Fourier transformed infrared(FTIR)spectroscopy identified surface-adsorbed functional groups.Scanning electron microscopy(SEM)and the specific surface area analyses by Brunauer-Emmett-Teller(BET)revealed a porous,homogeneous surface composed of strongly agglomerated spherical grains with an estimated average particle size of～35 nm,which corresponded to a large specific sur-face area of～81.5 m2/g.X-ray photoelectron spectroscopy(XPS)analysis indicated that Mn3O4 was composed of metallic cations(Mn4+,Mn3+,and Mn2+)and oxygen species(O2-,OH-and CO32-).The optical bandgap energy is～2.55 eV.Assessment of the catalytic performance of the Mn3O4 SPs indicated T90 conversion of CH4 to CO2 and H2O at 398 ℃ for gas hourly space velocity(GHSV)of 72000 mL3 g-1 h-1.This observed performance can be attributed to the cooperative effects of the smallest spherical grain size with a mesoporous structure,which is responsible for the larger specific surface area and available surface-active oxygenated species.The coopera-tive effect of the good reducibility,higher ratio of active species(OLat/OAds),and results of density functional theory(DFT)calculations suggested that the total oxidation of CH4 over the mesoporous Mn3O4 SPs might take place via a two-term process in which both the Langmuir-Hinshelwood and Mars-van Krevelen mechanisms are cooperatively involved.

Sol-gelManganese oxideCatalytic oxidationMethaneLangmuir-Hinshelwood mechanismMars-van Krevelen routeTwo-term process

Patrick Ndouka Ndouka、Stephane Kenmoe、Jacques Richard Mache、Elie Acayanka、Dick Hartmann Douma、Ralph Gebauer、Patrick Mountapmbeme Kouotou

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Department of Chemistry,Faculty of Sciences,University of Maroua,P.O.Box 814 Maroua,Cameroon

Department of Theoretical Chemistry,University of Duisburg-Essen,D-45141 Essen,Germany

Department of Mining Engineering,School of Geology and Mining Engineering,University of Ngaoundéré,P.O.Box 115 Meiganga,Cameroon

Department of Inorganic Chemistry,Faculty of Science,University of Yaoundé I,P.O.Box 812 Yaoundé Cameroon

Groupe de Simulations Numériques en Magnétisme et Catalyse,Faculté des Sciences et Techniques,Université Marien Ngouabi,B.P.69 Brazzaville,Congo

The Abdus Salam International Centre for Theoretical Physics(ICTP),34151 Trieste,Italy

National Advanced School of Engineering of Maroua,University of Maroua,P.O.Box 46 Maroua,Cameroon

Higher Institute of Agriculture,Wood,Water and Environment,University of Ebolowa,P.O.Box 118 Ebolowa,Cameroon

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2024

10.1016/j.chphma.2024.06.003

化学物理材料(英文)

化学物理材料(英文)

ISSN：
年,卷(期)：2024.3(3)