Synthesis Of PtRu Catalyst And Study On CO-Tolerance Of Hydrogen Fuel Cell Anode

At present,the electrode catalytic material of hydrogen fuel cell is mainly Pt-based catalyst,because so far,Pt element has the best performance and stability for hydrogen oxidation and oxygen reduction.However,trace CO in hydrogen produced by reforming of natural gas or liquid fuel will occupy the active site of Pt catalyst during the working process,resulting in CO poisoning.At present,Pt Ru catalyst is still considered to be the catalyst with the best resistance to CO poisoning.In this paper,the anti-CO ability of Pt Ru catalyst was improved from the perspectives of dual functional mechanism and electronic effect.Firstly,Pt Ru/C（N）catalyst was synthesized by homogeneous deposition of urea.Urea was used as nitrogen source and nitrogen-containing groups were added into the catalyst to prevent migration and agglomeration of annealed metal nanoparticles（NPS）at high temperature.The optimum reaction conditions were obtained at 95℃for 6 h,and the molar ratio of urea to metal was 80:1.The electrochemical active area of the catalyst was 142.53m²/g _{Pt Ru},which was nearly twice that of the commercial catalyst,77.96m²/g _{Pt Ru}.The alloying degree of Pt Ru/C（N）was improved by annealing at750℃,and the alloying degree and dispersion of Pt Ru/C were higher than that of commercial catalyst.In the constant current density test of the battery,the polarization loss of self-made catalyst is 0.117 V,and the polarization loss of commercial catalyst is 0.176 V,showing stronger CO resistance.The oscillation phenomenon in battery testing is systematically studied and the internal relationship between oscillation phenomenon and anode overpotential is revealed.Then Pt Ru O_xH_y was prepared by electrochemical in-situ oxidation of Pt Ru/C alloy catalyst to improve the dual-function effect of Pt Ru.The effect of synthesis potential and p H on the experiment was systematically studied,and Pt Ru O_xH_y was prepared in batches by spraying platinum plates,and the corresponding physical characterization was carried out.It was confirmed that the in-situ electrooxidation method can oxidize The Ru element in the surface phase of metal NPS into Ru O_xH_y,without changing the valence state of bulk phase alloy Ru.The bifunctional effect of catalyst was improved without changing the electronic effect of catalyst.Compared with the CO peak potential of 0.526 V vs.RHE of commercial catalyst,Pt Ru O_xH_y prepared in batches in this paper can reach 0.489 V vs.RHE,which greatly improves CO-tolerance.