Preparation Of Nitrogen-doped Platinum-based Bimetallic Catalyst And Study On Its Electrocatalytic Oxidation Performance Of Ethanol

Precious metals such as Pt,Pd and Ru exhibit high catalytic performance in the catalytic oxidation of ethanol for direct ethanol fuel cells.However,these noble metals were expensive and poor stability because intermediate substances were generated during the oxidation stage of the alcohol,these intermediate substances were adsorbed on the surface of the catalyst,which prevented further reaction of the catalyst.In addition,CO intermediate was produced during the alcohol reaction,which could poison a precious metal catalyst such as Pt.Bimetallic catalysts can effectively solve this problem.Therefore,bimetallic catalysts formed by platinum and other transition metal phases have become research hotspot in recent years.The research content of this work are as follows:In this work,urea was used as the nitrogen source,glucose was used as carbon source to synthesis catalyst,then the PtSn bimetallic was loaded on the carrier by the immersion reduction method.The catalysts of the Pt2Sn/NC,PtSn/NC and PtSn2/NC was prepared by changing the ratio of the two metal salt solutions.The results showed that the particle size of the metal was different,which affected the performance of the catalyst for the catalytic oxidation of ethanol.When the ratio of Pt to Sn is 1:2,the PtSrn2INC catalyst had the higher catalytic activity and good stability for ethanol oxidation.The average particle size of the metal particles was 2.4 nm,and the ethanol oxidation current density was 133.13 mA mg-1.In addition,the doping amount of urea and the type of transition metal were changed.It was found that when the urea content was 100 mg,the size of the catalyst carrier was uniform and the particle size of the metal nanoparticles was small.X-ray diffraction analysis and X-ray photoelectron spectroscopy analysis showed that an appropriate amount of nitrogen doping helped to reduce the Ptx+ to Pt0.The results of cyclic voltammetry and i-t curve showed that the activity and stability of Pt-based bimetallic catalyst synthesized by one-step method was higher than by the impregnation reduction method,and the catalytic performance of the Pt2Ni3/C-N3 was higher than Pt2Sn3/C-N3.The electrocatalytic performance of the catalyst was tested under the conditions of 0.5M H2SO4 and 1M ethanol.The catalytic performance of the Pt2Ni3/C-N3 reached 1454 mA-mg-1,which has high catalytic activity and stability.