Reserch For High Stability Of Platinum-based And Non-platinum Catalysts In Fuel Cell

In recent years,with the growing demand for energy,energy shortages and environmental pollution has become a serious problem bedeviling people,so the development of new clean energy and renewable energy is essential.Direct methanol fuel cells(DMFCs),which as a kind of clean energy,have many advantages such as high fuel efficiency,simple system structure,little environmental pollution and so on.The activity and stability of the electrocatalysts in DMFCs directly determine their efficiency and longevity.Therefore,it is important to prepare catalysts with high activity and high stability.The traditional Pt catalyst used sp~2 hybrid carbon material as the support,the carbon material support prone to oxidation collapse and a series of problems lead to catalyst deactivation.In this paper,the preparation of Pt catalysts with sp~2 hybridization of carbon nanotubes(CNT)as the basic material.Again which was subjected to a Ti plating process,and then in the process of transformation under N2 atmosphere to obtain a surface-modified support Ti_xN_y/CNT.Finally Pt/Ti_xN_y/CNT catalyst with Pt loading of20% was obtained by microwave method.The results show that the CNT surface is uniformly loaded with Ti_xN_y coating via the intermediate transition layer TiC and Ti,and the Pt metal particles are evenly anchored on the rough support surface.The catalytic performance of Pt/Ti_xN_y/CNT for anode methanol oxidation,cathodic oxygen reduction and stability of DMFCs was tested.The results show that Pt/Ti_xN_y/CNT has better catalytic activity for methanol oxidation and oxygen reduction compared to the conventional Pt/ C catalyst with 20% Pt loading,and has excellent stability as a catalyst.In order to avoid the high cost and limited resource of Pt metal catalyst,doping of non-platinum catalyst becomes the research focus.Commonly doped carbon-derived carbon catalysts still suffer from poor performance and poor stability.In this paper,N-CDC/WC,a nitrogen-doped core-shell catalyst,was prepared by tungsten carbide(WC)as the raw material through the two processes of acid etching and nitrogen heat treatment.Through WC and extract chloride CoCl2 and nitrogen source melamine mixing step heattreatment method of the preparation of the core-shell structure of Co,N codoping catalyst Co-N-CDC/WC.The electrochemical results show that the two kinds of non-platinum catalyst for catalytic ability of oxygen reduction are similar to 20% of the Pt/C catalyst,and the reaction process of them were all 4 electrons reaction.While the two catalysts also have applied to renewable fuel cells in the catalytic oxygen evolution reaction capacity and has a very good stability.