Synthesis, Characterization And Electrocatalytic Performance Of Crbon Spported Pt-based Anode Catalysts For Direct Methanol Fuel Cells

Direct methanol fuel cell is a promising candidate to satisfy the ever-increasing energy demand in future because of it’s relatively widely available resources of the fuel and safety for the storage and transportations, high-energy conversion, low pollution emissions, system simplicity. Howerer, the poor utilization coefficient and significantly high costs of Pt catalyst loading per unit area have limited their practical application in direct methanol fuel cell. To overcome the issues, synthesis of new anode catalysis, which it can substitute for the precious metal catalyst, is an effective way to promote the direct methanol fuel cell commercialization process. In this paper, new carbon-support Pt-based anode catalysts were fabricated and their electrochemical properties were studied in detail. The main topics and results of the thesis are sunnarized as follows:1. Platinum nanoparticles with uniformed size and high dispersion have been successfully assembled on PDDA functionalized graphene oxide via a sodium borohydride reduction process. The loading concentration of Pt NPs on graphene could be adjusted in the range of18～78wt%. The obtained Pt/graphene nanocomposites were characterized by TEM, HTEM, EDS, XRD, and TGA. Electrochemical studies revealed that the Pt/graphene nanocomposites with electrochemically active surface area of141.6m2/g showed excellent electrocatalytic activity toward methanol oxidation and oxygen reduction.2. A simple and facile method was developed to fabricate alloyed PtCu bimetallic nanoparticles on PDDA-functionalized graphene via NaBH4reduction process. The catalyst, PtCu/graphene, was characterized by TEM, HTEM, STEM, XPS, XRD and EDS. The electrocatalytic characteristics of the nanocatalysts for the methanol oxidation reaction were systematically investigated by cyclic voltammetry. The PtCu/graphene catalysts exhibit higher catalytic activity than Pt/graphene catalysts for the methanol oxidation reaction. Therefore, this work has demonstrated that a higher performance of the methanol oxidation reaction could be realized at the PtCu/graphene electrocatalyst while Pt utilization also could be greatly diminished.3. Dopamine is a natural neurotransmitter in the cells whose deficiency leads to Parkinson’s disease. Under the conditions of neutral solution with air, it changes into a polymeric precipitate, polydopamine, which has an aromatic structure with catechol groups and versatile functions. In this paper, we report an environment-friendly method to produce Pt-based catalysts that employs a biopolymer-polydopamine as the reductant and crosslinking agent. This study is the first example of the use of Pdop for nontoxic and scalable production of the Pt-based catalysts. Those Pt-based catalysts produced in this way has unique electrocatalytic activity toward methanol oxidation that are the same as those produced via other methods.