Research Branched Platinum Nanomaterials Synthesis And Electrochemical Properties Of The Control

Pt-based nanostructures have many special functional properties so they have many important applications in the field of catalysis, sensors, fuel cells, optical, electronic and magnetic devices and so on. These features are closely related to their morphologies and sizes. In this regard, a lot of studies have been focused on the controlled synthesis of Pt-based nanostructures with specific morphologies and sizes. With respect to morphology control, many platinum nanostructures have been reported including nanospheres, nanowires, nanotubes, nanocubes, nanowheels, nanocages, etc. In terms of size regulation, the traditional control strategy is seeding method:shaped metal seeds such as nanoparticles, nanorods, nanocubes and nanooctahedrals are firstly synthesized, then the seeds are added to the reaction system to separate the nucleation and growth process, guaranteeing every nucleation center has roughly equal growth time to achieve uniformity control of nanostructures and by varying the ratio of seeds and platinum precursor to achieve size control.In this thesis, zinc (II) porphyrin-based photocatalytic in situ seeding method is used to control the size and uniformity of the synthesized nanostructures. The reaction system was monitored by UV-vis spectrum and the prepared platinum nanodendrites were characterized by X-ray diffraction, transmission electron microscope and electrochemical measurements. The main conclusions are as follows:1. Platinum nanodendrites were prepared using zinc (II) porphyrin photocatalytic in situ seeding method, the average diameter and uniformity of these platinum nanodendrites was under control by tuned the concentration of seeds which can be achieved by changing irradiation time.2. The electrochemical activity surface area, mass activity and specific activity of prepared platinum nanodendrites were superior to that of commercial Pt black and the platinum nanodendrites showed high electrochemical activity towards methanol oxidation.