Synthesis Of Platinum And Platinum-Based Alloy Nanoparticle Networks And Their Electrocatalytic Activities Investigation

The world’s growing energy needs and environmental concerns have inspiredpeople to look for other energy or energy conversion pathways to replace fossil fuelssuch as diesel or gasoline. As a generating device, in fuel cell, fuels can be directlyconverted to electricity energy via an environmentally friendly and extremely efficientway. Thus, fuel cell technology is considered one of the most promising sources ofpower. Fuel cells often use Pt as electrocatalysts. However, Pt catalyst is not onlyeasily poisoned, but expensive. These disadvantages limit its practical applications.Therefore, it is a crucial task to explore poison-resistant and more activeelectrocatalysts. Up to date, among these catalysts, Pt-based bimetallic nanostructureis one kind of the most promising catalysts. For example, it has been demonstratedthat Pt-based alloy （Pt-Co, Pt-Ni） can effectively improve the anti-poisoning abilityand catalytic activities. Compared to their solid counterparts, porous ornetwork-structured metals and alloys have exhibited improved physical and chemicalperformance due to their high surface area, low density, and high gas permeability,which have been attracted extensive interest. Some approaches have been devoted tosynthesize Pt-based nanomaterials of porous or network-like. However, most of thesedocumented approaches usually require complex and multistep preparationprocedures, rigorous reaction conditions, and some of them are applicable to only oneor two metal. Or the synthesis processes of the Pt-based nanomaterials requiretemplates, and time-consuming. Thus, it is indispensable to develop a simple,universal, and room-temperature fast synthetic routes for creating network-like Pt andPt-based alloy nanomaterials and investigate their electrocatalytic activities.In order to reduce the cost of common catalysts and improve the electrocatalyticperformance of fuel cells, in the thesis, Pt nanoparticle networks （Pt NN） and Pt-basedalloy nanoparticle networks catalysts with well-controlled composition have been fastprepared through a room-temperature liquid phase coreduction method with ethyleneglycol （EG for short） assisted. SEM and other techniques showed that the networkstructure was composed of sub-10nm nanoparticles with irregular morphology.Moreover, electrochemical measurements showed that the as-synthesized Pt-based alloys exhibited remarkable composition-dependent catalytic activities for both smallorganic molecules oxidation and oxygen reduction reaction （ORR）. Thecorresponding research results are listed as follows:1. Pt NN and Pt-Ni alloy nanoparticle networks （Pt-Ni NN） withcomposition-controlled were prepared by a CTAB/water/chloroform two-phasecoreduction method at room temperature with an EG assisted. Among thecommercially available Pt/C, Pt NN, and Pt-Ni NN with different composition, Pt_1.5NiNN presented the highest activity and the best durability toward methanol and formicacid electrooxidation, while Pt2Ni NN showed the best electrocatalytic activities forORR.2. By improving the synthetic method, Pt NN and Pt-Pd alloy nanoparticlenetworks （Pt-Pd NN） with adjustable composition were prepared by aroom-temperature coreduction method with EG assisted. In particular, the Pt_0.80Pd_0.20NN had much enhanced electrocatalytic activity and better durability toward ethanoloxidation reaction over commercially available Pt black, Pt NN and other Pt-Pd NN.