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The Preparation And Electrocatalytical Performance Of Hydrogen Revolution Reaction Materials Derived From Molybdenum-based Compounds

Posted on:2017-05-28Degree:MasterType:Thesis
Country:ChinaCandidate:X X LiFull Text:PDF
GTID:2271330503460480Subject:Environmental Engineering
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This thesis is aimed at the existence proplem in the current electrocatalytic technology, such as the high price of platinum-based electrocatalytic, at low levels in the earth’s crust. The target is to develop the novel composite replacement for Pt-based catalysts. Molybdenum-based materials was chosed as non-noble metal catalysts for hydrogen evolution reaction to improve the electrocatalytical performance.The main research content is as follows:1. A non-noble metal catalyst of MoO2-modifed Mo2C/Graphene is prepared by pyrolysis precursor MoOx/amine hybrid nanowires and graphene under inert gas. The structure of MoO2-modifed MoC2/Graphene was characterized by N2 adsorption-desorption, X-ray diffraction, Transmission electron microscopy, and we investigated for the electrocatalytic activity and stability for HER in acidic, alkaline,neutral solution. According to linear sweep voltammetry, amperometric method, the MoO2 modifed Mo2C/Graphene electrocatalysts has excellent catalytic activity for hydrogen evolution reaction.2.The catalyst of Mo2C is prepared by pyrolysis physical mixtures which is potassium ferricyanide, ammonium molybdate and aniline under inert gas. In order to improve the electron and proton conductivity of materials, added C3N4 as basal to prepare Mo2C/g-C composties by the above method. The structure of Mo2C/g-C was characterized by X-ray diffraction, scanning electron microscopy, and we investigated for the electrocatalytic activity and stability for HER in acidic solution by linear sweep voltammetry, tafel curve. On the one hand, we can know that the electrocatalytic activity of Mo2C/g-C composties is better than Mo2C from electrochemical characterization. On the other hand, After 1M HCl washed the catalyst of Mo2C is the resulting acted as a highly active HER electrocatalyst with an extremely low onset potential of-0.217 V, a small Tafel solpe of 66 m V/dec, are better than the catalyst of Mo2C with an onset potential of-0.263 V, a Tafel solpe of95 m V/dec in 0.5M H2SO4.3.MoS2 is a well known catalyst for the hydrodesulfurization(HDS) reaction and is also used as a solid lubricant. In contrast, MoS2 was for a long time not considered as a promising HER catalyst because bulk MoS2 showed poor activity. On the one hand, it has poor conductivity as for hydrogen evolution reaction of materials. On the other hand, lack of amount of active sites. Based on the situation, we design thecarbon sphere method is used as a template for synthesis of molybdenum oxide. The flower-like MoS2 is prepared by pyrolysis that the physical mixtures of the above of molybdenum oxide and powdered sulfur under inert gas, and we investigated for the electrocatalytic activity and stability for HER in acidic, alkaline solution. The flower-like MoS2 is made up of many ultrathin nanosheets, the ultrathin nanosheets has provided a lot of active sites of the catalytic of HER. Besides, the robust structure show higher electrocatalytic activity because of it has more defect sites and a big surface area in the three-phase interface of the catalytic system.These aspects provoke significant contemporary interest in the investigation an development of the flower-like MoS2.
Keywords/Search Tags:Mo2C/Graphene, Mo2C/g-C, MoS2, HER
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