Preparation And Performance Of RE Molybdenum Carbide And Molybdenum Carbide

Using ordinary water synthesize three B-type structure Anderson polyo-xometalate (NH4)3[XMo6O24H6]·7H2O (abbreviated as XMo6, X = Fe, Cr, Ni), X-ray diffraction (XRD), Thermo-gravimetric differential thermal analysis (TG-DTA) were used to test its structure, Thermal stability of the characterization.to preparate of molybdenum carbide and RE molybdenum carbide,using XMo6 (X = Fe, Cr, Ni) as a precursor, respectively, with methanol as penetration agent or adding NdCl₃, LaCl₃, SmCl₃, GdCl₃ and mixed rare earth chloride as a penetration agent by RE-permeation at different temperature, And making a study on its structure, composition, morphology, valence and electrical properties, catalytic properties. The results showed : RE: Nd, La, Sm, Gd infiltrated into the molybdenum carbide surface phase and bulk, with complex reaction, Generating a new rare-earth compounds RE LnxMoyC molybdenum carbide, the electric performance has been significantly improved. It has certain catalytic properties for anodes In DMFC.The result of XRD characterization : RE molybdenum carbide crystal structure was a single hexagonal close-packed (hcp)β-Mo2C structure. XPS and EDX test results show that the rare earth elements Nd, Gd, La, Sm has entered molybdenum carbide crystal phase. Their valence and molar percentage are La³⁺ (0.19%), Nd³⁺ (0.18%), Sm³⁺ (0.17%) and Gd³⁺ (0.16%). Molecular Formula abbreviation is LnxMoyC. TG-DTA analysis of thermal stability tests showed : LnxMoyC stability than the current industrial semiconductor and dielectric materials coated molybdenum carbide coating. The GdxMoyC stability is also upgraded.The conductivity test's results show : Mo2C : 1.025×10² S·cm^-1, LnxMoyC : 4.692×10³ S·cm^-1, GdxMoyC: 2.002×10³ S·cm^-1. both higher than the current literature recorded the highest value of 1.025×10² S·cm^-1 at room temperature., the RE molybdenum carbide or molybdenum carbide conductive ,which the RE molybdenum carbide or molybdenum carbide were penetration on difference precursor, enhance with different rates; conductivity test at difference temperature shows that : LnxMoyC showed the metal character at 289 490 K, and there has been a significant semiconductor behaviorfrom 490⁵50 K. Mo=C shown the semiconductor in certain temperature range, but is not obvious as LnxMoyC.In Direct Methanol Fuel Cell (DMFC) system, we tried to make a study on RE molybdenum carbide LnxMoyC electro-catalytic properties of electrochemical testing, at methanol oxidation potential of 0.8V, appeared strong oxidation peak. Note LnxMoyC/C shows it's catalytic role. BET test result shows that LnxMoyC surface area is 40 m², the size test analysis show that it's particle size distribution is uneven. That is likely to affect the catalytic properties.