Preparation Of Pt-based Nanocomposite Catalyst And Its Electrooxidation Performance In Methanol

Direct methanol fuel cell(DMFC),as an efficient and environmentally friendly energy conversion device,has been widely concerned.However,due to the high cost and CO toxicity of traditional anodic platinum(Pt)catalysts,the commercial development of DMFC is limited.Therefore,the search for catalysts with high activity and high stability is the key factor for the breakthrough of DMFC technology.Currently,strategies to reduce the amount of Pt and improve its catalytic activity include adjusting morphology and size,alloying with other metals,and preparing supported nanocomposites.Therefore,the following work was carried out in this paper to improve the performance of anodic methanol electrooxidation reaction(MOR)of Pt-based catalysts in DMFC:In Chapter 3,a series of alloy Pt-M(M = Fe,Co and Ni)nanowires catalysts were synthesized by a simple one-pot method by adjusting the molar ratio of Pt and transition metal(M).The one Vinamil structure of Pt-M has a large specific surface area and superior flexibility,thus promoting the exposure of more active sites;In addition,the transition metal M bonded with Pt and electrons transferred from M to Pt,which changed the electronic properties of Pt.At the same time,the synergistic effect of the two metals existed on the catalyst surface,which made it show better MOR catalytic activity and stability under both acidic and basic conditions.In the fourth chapter,the rare earth element lanthanum(La)was introduced into the process of the alloy Pt Co nanowires catalyst prepared in the third chapter.By regulating the doping amount of La,a series of Pt Co nanoalloy catalysts doped with different contents of La were successfully prepared.Due to the unique 4f electron configuration and physical and chemical properties of rare earth elements,the electronic structure of the catalyst can be effectively regulated by doping and modification,and the surface characteristics can be optimized.Therefore,the synthesized Pt Co-x La nano-electrocatalyst shows better MOR catalytic activity and stability.In Chapter 5,bimetallic molybdenum carbide tungsten hybrid reduced graphene oxide(Pt/Mo WC/r GO)composite catalysts supported by Pt nanoparticles were prepared by hard template method.The catalyst has a highly dispersed ultra-fine bimetallic molybdenum carbide tungsten nanocrystalline and mesoporous structure,and the hybrid of carbide and graphene can form a unique layered structure,providing a large number of active sites.In addition,the strong interaction between bimetallic molybdenum carbide tungsten and graphene nanosheets can not only accelerate the charge transfer efficiency,but also increase the electrochemically active surface area,so that it shows excellent MOR catalytic activity and stability in both acidic and alkaline electrolytes.