Study On Synthesis Of PdBi Alloy Nanoparticles And Their Catalytic Performance For Formic Acid

Fuel cell is a kind of sustainable new energy,which can convert chemical energy directly into electric energy through chemical reaction.Direct formic acid fuel cell has attracted much attention because of its high power density,convenient storage,and non-toxicity.Generally speaking,anode catalyst of fuel cell is the critical part.Pd-based and Pt-based catalysts are commonly used in formic acid fuel cell.Because the cost of Pd-based catalyst is relatively low and the anti-poisoning effect of CO is relatively strong,Pd-based catalysts are more suitable for catalytic oxidation of formic acid.The catalytic activity and stability of pure Pd catalyst for the catalytic oxidation of formic acid are not very high.When the second metal is added to the Pd catalyst to form bimetallic or alloy structure with Pd,the catalytic activity and stability can be improved.Among the many methods of catalyst,liquid phase reduction is an efficient,simple and easy-to-operate synthesis method,so it is widely used in the preparation of nano-particle catalysts.In this paper,PdBi alloy nanoparticles were synthesized by liquid phase reduction method.The main studies are as follows:（1）The PdBi alloy nanoparticles with good dispersion and uniform particle size were synthesized by controlling the conditions in the synthesis process,such as,the amount of reducing agent,the dosage of PVP and the reaction temperature.The results showed that when the dosage of reducing agent was 90 mg,PVP was 100 g and the reaction temperature was 80℃,the nano-particles with good dispersion and uniform particle size could be obtained.（2）The morphology,phase structure and electronic structure of PdBi alloy nanoparticles were studied by transmission electron microscopy（TEM）,X-ray diffraction（XRD）and X-ray photoelectron spectra（XPS）.The results shown that the synthesized PdBi nanoparticles are alloy nanoparticles with face-centered cubic（fcc）structure.（3）The electrocatalytic properties of PdBi alloy nanoparticles were studied by electrochemical measurements.The catalytic mass current density of PdBi alloy nanoparticles was 1.44 A?mg^-1,which was 4.8 times higher than that of commercial Pd/C.At the same time,Pd₁Bi₁ alloy nanoparticles have faster mass transfer rate for the oxidation of formic acid.The electrocatalytic oxidation of formic acid with PdBi nanoparticles was more stable than that of commercial Pd/C.The results show that the electron transfer and synergistic action between Pd and Bi made PdBi alloy nanoparticles have better catalytic performance to oxidize formic acid.