Synthesis,Characterization And Electrocatalytic Properties Of Platinum-based Composites

The advent of direct methanol fuel cell(DMFC)provides a new idea to solve the current energy shortage.Due to its fast start-up,cleanliness and high energy density,it has attracted a great deal of attention from researchers.Currently,Pt/C catalysts are widely used as anode or cathode catalysts for direct methanol fuel cells to catalyze methanol oxidation reactions(MOR)or oxygen reduction reactions(ORR).However,as the Pt metal is precious,scarce,costly,besides,its poor durability,susceptibility to poisoning and other problem hindered the DMFC application widely.Thus,the research and development of stable and green catalysts that are effective for catalyzing MOR and ORR is highly desirable and considered to be a major challenge.In summary,the work in this dissertation is divided into two parts as follows:1.POM-coated Pt nanoparticles on multi-layer graphene oxide were synthesized by a simple and convenient method using nickel foam as the conductive substrate.Four different Pt loadings of electrocatalysts were obtained by adjusting the concentration of chloroplatinic acid and named PPGN-n(n = 1,2,3,4).All electrocatalysts were higher than commercial Pt/C catalysts for methanol oxidation electrochemistry activity.During synthesis,POMs are bifunctional reagents that reduced chloroplatinic acid as a reducing agent while also controlling the particle size of Pt nanoparticles as a stabilizer.The methods provide new ideas for the design and preparation of electrocatalysts.2.The PtNi alloy catalyst was directly synthesized by one-step reduction at room temperature.By changing the molar ratio of platinum salt and nickel salt in the solution,five kinds of PtNi alloy granular catalysts with different proportions of platinum and nickel were finally obtained.The synthesis process is simple and green.The results show that the PtNi-4 alloy catalyst exhibits a good electrochemical activity towards MOR,additionally,its onset potential and current density towarsd ORR are similar to that of commercial Pt/C.Therefore,the PtNi-4 alloy catalyst can be used as an applicable direct methanol fuel cell anode and cathode catalyst for catalyzing MOR and ORR.