Study On Anodic Electrocatalysts Of Direct Liquid Fuel Cell

As a friendly energy-generating device for portable electronic devices, direct methanol fuel cells (DMFC), direct ethanol fuel cells (DEFC) and direct formic acid fuel cells (DFAFC) have been quickly developed in the past decades. Their commercialization, however, is still impeded by low performance, catalyst poisoning and high cost considerations of metal anodic catalyst. Searching novel anodic catalysts, improveing the synthesis procedures of the anodic catalysts and seeking the suitable catalyst supports are the key ways to overcome these problems.Some new anodic catalysts and anodic catalyst supports were prepared in this thesis and their electrochemcal properties were investigated in detail. The main results obtained in this thesis are as follows:1. A new carbon nanotubes wrapped with CNX layer (CNX@CNTs) was synthesized from carbonization of the ethylenediamine-decorated carbon nanotubes and used as catalyst support for methanol oxidation. Pt-Ru nanoparticles were highly dispersed on CNX@CNTs. The electrocatalytic properties of PtRu/CNX@CNTs for methanol oxidation have been investigated in 1.0 M CH3OH + 0.1 M H2SO4 aqueous solution by cycle voltammetry (CV), chronopotentiometry (E-T) and electrochemical impedance spectroscopy (EIS). Compared with PtRu/CNTs/graphite electrode, PtRu/CNX@CNTs/graphite electrode exhibited higher electrocatalytic activity and anti-poisoning ability. The results show that the doping of the nitrogen on the surface layer of the carbon nanotubes effectively enhances the electrocatalytic activities of PtRu/CNTs/graphite electrode, CNx@CNTs are the promising catalyst support for methanol electrooxidation.2. Carbon nanotubes supported Pt-Sn (Pt-Sn/CNTs) nanoparticles were prepared by using a replacement reaction method. The electrocatalytic activity of Pt-Sn/CNTs for ethanol electrooxidation was investigated by cyclic voltammetry in a 1.0 M CH3CH2OH + 0.5 M H2SO4 solution. The results show that the obtained Pt-Sn/CNT nanoparticles exhibit higher electrocatalytic activity and better long-term stability for ethanol oxidation compared to the PtSn/CNT nanoparticles prepared by the conventional co-reduction method.3. 2, 2'-bipyridin-functionalized graphene nanosheets (Bpy-G) were synthesized using the noncovalent functionalization for the first time, and subsequently acted as the support for the PtPd nanoparticles in the direct formic acid fuel cell. The noncovalent functionalization maintains the perfect nanostructure of the graphene nanosheets and its physicochemical properties. The electrochemical results show that the catalystic activity of PtPd nanoparticles supported on the Bpy-G for formic acid electrooxidation is remarkably improved, obviously.