A Study On Carbon Nanotube Bridged PtCoNi Alloy Nanoparticles Catalyst For The Oxygen Reduction Reaction

With the development of non-fuel vehicles,proton exchange membrane fuel cell（PEMFC）,which is the most suitable fuel cell for fuel cell vehicles（FCV）,has attracted extensive attention all over the world.The key to the commercialization of the battery is to reduce the cost of the catalyst,develop Pt-based oxygen reduction catalysts with high activity and stability,and realize their large-scale industrial production.At present,Pt-based alloy catalyst is one of the most commonly used oxygen reduction catalysts.However,when the fuel cell runs for a long time,the catalyst still has some problems,such as agglomeration of alloy particles,dissolution of non-precious metals and blocked material transport channels,which lead to poor catalytic activity and poor stability.At the same time,the preparation method of catalyst is complicated and the metal doping is not easy to control,which leads to many excellent catalysts can not be industrialized preparation.In order to solve the above problems,carbon nanotubes bridged Pt-based ternary alloy catalyst was prepared in this paper,and the influence of alloy composition and structure on the activity and stability of the catalyst was explored.At the same time,in order to realize the industrial production of oxygen reduction catalyst,this paper explores the synthesis of catalyst by flow control technology,which provides an effective strategy for realizing the one-pot production of catalyst.The results show that the Pt alloying is beneficial to improve the intrinsic activity of the catalyst,and the complex synergistic effect between Pt and carbon nanotube supports is beneficial to improve the stability of the catalyst,and limit its aggregation under operating conditions and the blockage of material transport channels.The results showed that Pt Co Ni_0.4@CNTs catalyst had high catalytic activity and good stability.（1）At 0.9 V,the mass activity and specific surface area activity of Pt/C were 626m A·mg_Pt^-1 and 2.14 m A·cm^-2,which were 3.7 times and 8.9 times higher than those of commercial Pt/C(166 m A·mg_Pt^-1 and 0.24 m A·cm^-2),respectively.It is 2 times and 3.1times that of Pt3Ni/C(308 m A·mg_Pt^-1,0.7 m A·cm^-2).（2）After 50,000 cycles of accelerated aging experiment,its half-wave potential only attenuates 10 m V,which is far better than that of commercial PT/C（40m V）.Secondly,the preparation technology of the catalyst was explored.The Pt Co@CNTs-MOF catalyst was synthesized at the rate of 5r/min by flow control technique.The catalyst is composed of carbon nanotubes bridging Pt-Co particles together,and the Pt-Co metals are evenly dispersed in the catalyst,showing excellent catalytic activity and stability of oxygen reduction.The results showed that（1）The mass activity and specific surface area activity of the catalyst were 515 m A·mg_Pt^-1 and1.17 m A·cm^-2at 0.9V,respectively,when the Pt loading was 10%,which were 3.1times and 4.9 times higher than those of commercial Pt/C(166 m A·mg_Pt^-1 and 0.24m A·cm^-2).（2）After 10,000 cycles of accelerated aging experiment,the half-wave potential has no attenuation,which is far better than that of commercial Pt/C（attenuation 20 m V）.（3）In the fuel cell system,when the cathode load is 60μg _Pt·cm^-2,the power density reaches 958 m W·cm^-2,and only 0.05 A·cm^-2 attenuation is detected after 100 hours of continuous operation.