Abstract:
A novel La-Co-O-C(LC-C)composites were prepared via a facile co-hydrothermal route with oxides and glycerol and further optimized for methane catalytic activity and thermal stability via component regulation.It was demonstrated that Co3O4 phase was the main component in regulation.The combined results of X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption of oxygen(O2-TPD),temperature-programmed reduc-tion of hydrogen(H2-TPR),temperature-programmed desorption of ammonia/carbon diox-ide(NH3/CO2-TPD)revealed that component regulation led to more oxygen vacancies and exposure of surface Co2+,lower surface basicity and optimized acidity,which were benefi-cial for adsorption of active oxygen species and activation of methane molecules,resulting in the excellent catalytic oxidation performance.Especially,the(3.5)LC-C(3.5 is Co-to-La molar ratio)showed the optimum activity and the T50 and T90(the temperature at which the CH4 conversion rate was 50%and 90%,respectively)were 318 and 367℃,respectively.Using theoretical calculations and in situ diffuse reflection infrared Fourier transform spec-troscopy characterization,it was also found that the catalytic mechanism changes from the"Rideal-Eley"mechanism to the"Two-term"mechanism depending on the temperature win-dows in which the reaction takes place.Besides,the use of the"Flynn-Wall-Ozawa"model in thermoanalytical kinetics revealed that component regulation simultaneously optimized the decomposition activation energy,further expanding the application scope of carbon-containing composites.
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Source :
环境科学学报(英文版)
ISSN: 1001-0742
Year: 2023
Issue: 4
Volume: 126
Page: 459-469
6 . 9 0 0
JCR@2022
ESI Discipline: ENVIRONMENT/ECOLOGY;
ESI HC Threshold:17
Cited Count:
WoS CC Cited Count: 0
SCOPUS Cited Count:
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count: -1
Chinese Cited Count:
30 Days PV: 11
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