A Study On Electrocatalytic Performance For Formic Acid Of Functionalized Titanium Carbide Supported Pd-based Multi-component Catalysts

Direct formic acid fuel cell has been widely used in power vehicles and electronic equipment because of its high energy density,safety and non-toxicity.However,the cost of anode catalyst for DFAFC is high,and the catalytic activity and efficiency have not reached the requirement of commercial application.In recent decades,researchers have made great efforts on the aspects of catalyst carrier material,morphology,composition and so on,in order to reduce the amount of precious metal Pd,improve its utilization rate and enhance its catalytic performance for oxidation of formic acid.In this paper,the catalytic performance of Pd catalyst and its binary and ternary catalysts,a polymer modified titanium carbide as a new catalyst carrier,for the electrooxidation of formic acid was studied from the aspects of modification of support,cost and performance of catalyst.The main contents are as follows:?1?The surface of titanium carbide was modified with ionic polymers and used as the support of Pd catalyst.The influence of polymer modified support on the catalyst was studied.At the same time,the effect of catalyst on catalytic performance of formic acid oxidation was also discussed.The results show that the Pd particles are uniformly dispersed on the surface of modified titanium carbide,the particle size is small,and electrochemical activity and stability are also improved,which may be due to the coordination of N,S atoms in the polymer with Pd metal.This could enables Pd particles to be uniformly and stably loaded on titanium carbide by coordination,and the interaction can change the electronic state of Pd surface and improve th e catalytic performance of nanoparticles.?2?In order to further improve the activity of the catalyst for formic acid,the second kind of metal Ru was added to form binary alloy catalyst.The results showed that the electronic effect and synergistic effect between Pd and Ru could enhance the electrochemical performance of the catalyst.At the same time,the surface of Ru can decompose water to form hydroxyl species,which can help the CO_ads poisoning species to be further oxidized and improve their ability to resist CO _ads poisoning.Moreover,the catalytic activity of PdRu/TiC?P?catalyst is the best when the atomic ratio of Pd and Ru is 3:1.?3?On the basis of PdRu/TiC?P?catalyst,the addition of base metal Sn,reduces the amount of precious metal and the cost of catalyst at the same time.The results of TEM showed that the particle size of PdRuSn ternary alloy catalyst increased slightly and the lattice spacing expands slightly with the addition of Sn,indicating that the alloy structure maybe formed.A series of electrochemical results also showed that PdRuSn/TiC?P?has a good catalytic activity for formic acid,which may be due to the fact that the addition of Sn further enhances the interaction between metals and weakens the adsorption strength of CO_ads on Pd surface.It is beneficial to the removal of CO_ads and the improvement of performance.We also discussed the performance of different proportion of PdRuSn/TiC?P?catalysts,and found that the catalyst showed the best catalytic performance when the metal atomic ratio was 3:1:1.