Branched Platinum Based On Nanocomposites:Controllable Synthesis And Electrocatalytical Application

Three-dimensional(3D) dendritic platinum nanostructures(DPNs), with its characteristic structure, high surface area, and sufficient reactive sites, showed an excellent catalytic efficiency and a widely application prospect in the field of electrochemistry. A suitable support for platinum nanoparticles is a critical component for improving catalytical activity and minimizing the utlition of platinum. Rcently, carbon nanomaterilas with large surface area, high electrical conductivity, and high chemical stability, represent a highly interesting support for noble metallic nanocatalysts. In this thesis, we carried out a series of systematic research work on controlled synthesis, assembly and electrocatalytic and sensing applications of Pt-based nanomaterials. The major achievements are outlined as following:1. Macroporous carbon(MPC) with high pore accessibility and electrical conductivity is of great interest to the electrochemical platform. The development of a simple and efficient route for the direct synthesis of dendritic platinum nanoparticle(DPN) decorated MPC(DPN/MPC) is an interesting challenge, which is highly valuable for electrocatalytic applications. In this study, we propose a very simple route for the one-step synthesis of DPN/MPC in aqueous solution at room temperature without the need for any kind of seed and surfactant to direct the dendritic growth of Pt nanoparticles, which is performed by simply mixing an aqueous solution of K2 Pt Cl4 with MPC and formic acid. The as-prepared DPN/MPC shows high electrocatalytic activities toward the oxidation of methanol and glucose.2. The morphology- and sizecontrolled synthesis of branched Pt nanostructures on graphene is highly favorable for enhancing the electrocatalytic activity and stability of Pt. Herein, a facile approach is developed for the efficient synthesis of well-dispersed Pt nanoflowers(Pt NFs) on the surface of polydopamine(PDA)-modified reduced graphene oxide(PDRGO), denoted as Pt NFs/PDRGO, in high yield. The synthesis was performed by a simple heating treatment of an aqueous solution that contained K2 Pt Cl4 and PDA-modified graphene oxide(GO) without the need for any additional reducing agent, seed, surfactant, or organic solvent. The coated PDA serves not only as a reducing agent, but also as cross-linker to anchor and stabilize Pt NFs on the PDRGO support. The as-prepared Pt NFs/PDRGO hybrid, with spatially and locally separated Pt NFs on PDRGO, exhibits superior electrocatalytic activity and stability toward both methanol oxidation reaction(MOR) and oxygen reduction reaction(ORR) in alkaline solutions.