On Catalytic Performance Of Platinum-based Rare Earth-doped Oxide Film Electrodes Of Post-processing

Pt-based catalyst had a wide range of applications in petroleum,chemical industry,energy and so on. The investigation of the catalyst with low-cost, high activity, high reliability and long life have been the warm spot of researches. The copper can be alloyed with the main phase and improved the particle distribution of the main catalytic phase. When mixed with precious metal, the Ce had the great co-catalysis performance, such as the improvement of oxygen storage and evolution ability of catalyst, the liquidity of lattice oxygen, the thermal stability and dispersion. So, the research of Pt-based membrane electrode doped with Ce is expected to prepare the catalyst with low platinum loading capacity but high catalytic performance, which supported on substrate can cut cost largely and insure high catalytic activity.This paper researches focused on the influence of post-processing with Pt-based catalyst electrochemical performance and its structure.The platinum loading capacity of catalyst could be further reduced while its catalyst activity improved by different post-treatment conditions, this can be referenced by such research in future.Series of samples included simple-layer film, double-layer film and three-layer film have been prepared by ion beam sputtering techniques (IBS) from "multi-purpose high vacuum ion beam sputtering and electron beam evaporation coating machine".The prepared samples were proceed post-treatment with different annealing temperature and different acid treatment conditions, then the electrochemical performance was tested by cyclic voltammetry(CV) and linear sweep voltammetry(LSV).After picked over, the microstructure and component content of film in membrane electrode have been analysed by inductively coupled plasma atomic emission spectrometry (1CP-AES), X-ray diffraction (XRD), scanning electronic microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission Electron Microscopes(HRTEM) and so on. The results showed that:(1) Electrochemical analysis:The electro-catalytic activity of a series of Pt-based doped with Ce membrane catalyst have been tested by CV and LSV.It could be found that proper post-treatment can realize in reducing Pt loading meanwhile improve the performance of electro-catalytic activity.That expanded the application of Pt-based catalyst in fuel cell.(2) Structural analysis:The crystal structure of Pt-based catalyst membrane was fcc, and the host phase was Pt(111).The effect of CeOx additives was refined grain,and the valence state of Ce was different in multilayer membrane.The grain size of samples would increase with annealing temperature increase.After acid treatment, the membrane surface will be erosion, morphology will be roughen, and each element content of samples surface will be reduced, that can greatly improve the utilization of active material.The HRTEM results showed that after acid treatment,the Cu in surface layer or in Pt-Cu alloy would be removed,that resulted to the interplanar distance of Pt-Pt decreased, and the overlap electron density between Pt-Pt, the activity position of Pt, the utilization rate of Pt, the catalytic activity of samples were increased.The XPS study found that, Pt transfer electronic to CeOx in the interaction of La and Pt,and in the membrane surface have a lot of O-ions. This reaction was similar with the O space model.