Controllable Synthesis And Catalytic Performance Of Pt-Based Nanocrystals

Pt-based nanocrystals are a very important type of electrocatalysts,and their electrocatalytic properties are strongly dependent on their morphology,composition,and structure.Therefore,the controlled synthesis of Pt-based nanocrystals is critical,and is the hot research issue in these years.Adjusting the structure of elemental Pt nanocrystals is a typical method to improve catalytic activity and stability,and replacing the Pt with a transition metal to form an alloy is another important strategy for improving electrocatalytic activity and reducing cost.Based on these two points,this paper selects a series of organic small molecule reducing agents such as triisopropylsilane and ascorbic acid to regulate the structure and size of Pt-based nanocrystals?Pt,Pt-Cu and Pt-Co?,and evaluates the electrocatalytic performance of some products.It mainly consists of the following three parts:1.Taking use of Pt?acac?₂ as the metal precursor,Pt nanocrystals with a multi-pod structure were prepared by various small organic reducing agents such as triisopropylsilane and ascorbic acid.By adjusting the type and amount of the small molecule reducing agents,the control of their pod lengths and diameters are realized,and their electrocatalytic activity for oxygen reduction reaction is evaluated.Two nanostructured catalysts with ORR specific activity much higher than commercial Pt/C were obtained.2.Based on the above experiments,Cu?acac?₂ as the copper source is introduced into the reaction system to synthesize octahedral?configuration?Pt-Cu alloy nanocrystals with a hierarchical structure.The structure and size of them are controlled by adjusting the type and amount of reducing agents.Two nanostructured catalysts with ORR specific activity much higher than commercial Pt/C are obtained.3.Additionally,a cobalt source?Co?acac?₂?is introduced into the reaction media to prepare cubic?configuration?Pt-Co alloy nanocrystals with a hierarchical structure.The structure of the obtained nanocrystals is also effectively regulated by changing the type and amount of the reducing agent.