Controlled Preparation And Electrocatalytic Performance Application Of Pt-based Nanocatalysts

Proton exchange membrane fuel cells have attracted increasing attention as sustainable energy conversion devices and are considered to be an excellent alternative to fossil energy sources.The Pt catalyst,as the recognized active catalyst,plays an irreplaceable role in determining whether the fuel cell can operate efficiently,rapidly and stably.However,the development of Pt catalysts is greatly limited by the small reserves of precious metal Pt,which is expensive and has low utilization,easy poisoning and poor stability.In the current study,Pt-based catalyst performance can be improved through strategies such as morphology modulation,composition modulation,and stability support materials.Therefore,in this paper,based on these three strategies,Pt-based nanocatalysts with excellent performance were modulated and prepared,and their electrocatalytic applications were studied and discussed,which are of great significance for an in-depth understanding of the oxidation mechanism of formic acid and provide a feasible and promising strategy for further improving the catalytic performance of the catalysts.The main studies are as follows:(1)Based on the composition control strategy,we prepared PtAu/C series catalysts with different bimetallic composition by adjusting the ratio of precursors,and explored the relationship between bimetallic composition and formic acid oxidation activity.The results showed that the nanoparticle size gradually increased with the increase of Au content,indicating that the pre-deposition of Pt on carbon facilitated the average size of Au nanoparticles to become smaller.And the electrocatalytic application to formic acid oxidation showed that the dehydrogenation selectivity of the direct pathway of formic acid oxidation increased with increasing Au,but the overall activity would first increase and then decrease,and the catalytic activity and stability were best at Pt:Au = 1:1,with the specific and mass activities being 16.8 and 10.7 times higher than Pt/C,respectively.(2)Based on the strategy of composition control and stable support,we prepared a series of PtAu/CoNC catalysts with different bimetallic components supported on metal organic frameworks(MOFs)-derived heteroatom doped carbon materials by ultrasound assisted method.They were characterized and compared for the electrocatalytic application of for formic acid oxidation,and the results showed the best catalytic activity and stability at Pt:Au = 1:1,with better performance than both PtAu/C(1:1)and Pt/C,with 2.4 and 26 times higher mass activity,respectively.The excellent properties are mainly attributed to the synergistic effect between the two metals,specific components and heteroatom doped carbon carriers.All of these are beneficial to optimize the activity and selectivity of direct reaction pathway,thus improving the catalytic activity of FAOR.(3)Based on the strategy of morphology control and composition control,we prepared PtCuPd ternary metal nanocatalysts in an autoclave by one-step hydrothermal method and adjusting the ratio of the added precursors..The results showed that the high Cu content tended to generate triangular-shaped samples.And the electrocatalytic application to formic acid oxidation showed that the catalytic FAO activity and stability of the ternary metal catalysts were significantly enhanced by the addition of Pd compared to the binary Pt Cu,which was attributed to the electron transfer between Pd,Cu and Pt,resulting in the decrease of the d-band center of Pt.