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The Electrocatalytic Oxidation Of Tungsten Carbide As Pd、Pt Catalyst Carrier For Small Organic Molecules

Posted on:2016-11-08Degree:MasterType:Thesis
Country:ChinaCandidate:Y X ZhangFull Text:PDF
GTID:2271330470961621Subject:Physical chemistry
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A fuel cell is an efficient power generator that can directly convert chemical energy into electrical energy not need to burn. Therefore, It is called the fourth power generation technologies.following the fire, hydro and nuclear. It does not go through the process of heat engine,therefore does not restrict by Carnot cycle, has high energy conversion efficiency, and low environmental pollution. It is considered the first choice for the 21 st century that is clean and efficient power generation technology, Although fuel cells have matured, there is a certain distance to commercialization. The activity and stability of electro-catalyst is one of the most critical factors in the fuel cell performance. Improving the catalyst activity and stability can improve the electrochemical performance of the entire cell. The stability of the catalyst relate to the active component, but also to the catalyst support material and loading way especially closely related to the interaction between the active ingredient and the carrier.In this paper, carbon is Vulcan XC-72 R carbon that has good electrical conductivity and high specific surface area. By soakage and high temperature heat reduction method, reducte ammonium tungstate in activated carbon surface, and form a carrier coated tungsten carbide structure. And C@WC has been prepareded use for the preparationof carrier Pd-based catalyst and Pt-based catalysts.This article discusses the impact of different W:C atomic and different preparation methods for the preparation of the catalyst. The study found that tungsten carbide mainly is in the form of the WC, W2 C in C@WC-6、C@WC-7and C@WC-8 carrier of W:C atomic 1:10、1:15 and 1:20; The catalysts that were preparation by this carrier have a higher catalytic oxidation activity.C@WC were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), thermogravimetry(TG) and other means. By XRD,the component of catalyst supports are discussed; By cyclic voltammetry(CV), chronoamperometry curve method(CA), and potential step method for the catalytic attenuation of activity and stability are discussed.The compare impact to Pd/C@WC catalysts by the conventional chemical synthesis method and microwave assisted synthesis. The study found that the catalyst have the higher activity and stability by the conventional chemical synthesis method.The electrochemical properties and surface topography of carrier of W:C atomic 1:10、1:15 and 1:20 are compared. The electochemical oxidation performance of Pd/C@WC-6、Pd/C@WC-7 and Pd/C@WC-8 for formic acid are compared. The study found that catalysts that are made of C@WC-7 have the higher activity and stability for formic acid.Pt/C@WC-6 、 Pt/C@WC-7 and Pt/C@WC-8 are preparation by C@WC-6 、C@WC-7 and C@WC-8 carriers, and The electrooxidation performance for methanol and ethanol of three catalysts are researched. The study found that catalysts that are made of C@WC-7 have the higher activity and stability for methanol and ethanol.
Keywords/Search Tags:Pd, Pt, C@WC, Methanol, Ethanol, formic acid, electrocatalytic oxidation
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