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Indexed by:期刊论文

Date of Publication:2011-06-01

Journal:Gongneng Cailiao/Journal of Functional Materials

Included Journals:EI、PKU、ISTIC、Scopus

Volume:42

Issue:SUPPL. JUNE

Page Number:419-422

ISSN No.:10019731

Abstract:Molybdenum carbides/carbon composites (MCCs) with high specific surface area were prepared using the direct carbonization of a mixture of hydroxylpropyl cellulose, polyvinyl alcohol, K2MoO4 and K2CO3 at 900  C in flowing Ar. X-ray diffraction (XRD), thermogravimetric analysis (TG), scanning electron microscopy (SEM) and electrochemical tests were used to characterize the prepared MCCs. X-ray diffraction pattern showed the formation of   -Mo2C with small amount of Mo3C2 in carbon matrix. The BET specific surface area varied from 400 to 1000 m2/g depending on the amount of K2CO3 added during the preparation. The redox peaks observed on the CV curves could be attributed to hydrated molybdenum oxides due to the slow oxidation of molybdenum carbides during the charge-discharge process. The pseudocapacitance resulted from the following Faradaic reactions of hydrated molybdenum oxides was superimposed on the double-layer capacitance of the carbon support, which increased the specific capacity. Parts of samples could still retain a high capacity (>150 F/g) at a current density of 1 A/g during the galvanostatic charge-discharge measurements, showing favorable electrochemical properties.