| Owing to the large specific surface area, unique pore structure and excellent structure stability, porous materials have shown superior performance as electrode material for energy storage and conversion. In this thesis, the porous carbon materials and porous noble metal alloys were prepared. Their structures and electrochemical properties were investigated.The acacia gum was used as a natural precursor to synthesize microporous carbon for energy storage application. The microporous carbons were synthesized by hydrothermal carbonization of acacia gum at 180℃, and subsequent activation by KOH at temperatures in the range of 700-900℃. The carbon materials possess well-controlled pore size distribution and high surface area. Moreover, the porosity can be finely tuned by modifying the activation temperatures. The influence of the porosity of the carbon materials on their capacitive performance was investigated. The superior charge storage capability with specific capacitance up to 272 F g-1 at current density of 1Ag-1 in 6 M KOH was achieved by the as-prepared microporous carbons.Porous carbon spheres (PCSs) are prepared via a facile hydrothermal carbonization and chemical activation route with pectin as the biomass precursor. The as-obtained PCSs present a large specific surface area (2440 m2g-1), well-balanced micro/mesoporosity with narrow pore size distribution and high content of oxygen-containing functional groups. The structure features make the PCSs an ideal electrode material for electrochemical energy storage. As electrode material for supercapacitors, the PCSs exhibit a high specific capacitance, good rate capacity and cycling stability. Furthermore, the PCSs show attractive property as support material for Pt electrocatalysts. Pt nanowires (PtNWs) grown on the PCSs interconnect with each other to form a porous nanowires network structure. The three-dimensional (3D) hybrid catalyst material consisting of PtNWs network supported on PCSs exhibit superior catalytic activity and stability towards both methanol and ethanol electro-oxidation in acidic media. In addition, owing to the rich presence of surface oxygen groups on PCSs, the CO-poisoning tolerance of the supported Pt nanowires is greatly promoted.Porous hollow carbon spheres (PHCSs) are prepared through hydrothermal carbonization of alginic acid and subsequent chemical activation by KOH. The porosity of the alginic acid derived PHCSs can be finely modulated by varying activation temperature in the range of 600-900℃. The PHCSs activated at 900℃ possess the largest specific surface area (2421 m2g-1), well-balanced micro- and mesoporosity, as well as high content of oxygen-containing functional groups. As the electrode material for supercapacitors, the PHCSs exhibit superior capacitive performance with specific capacitance of 314 F g-1 at current density of 1 A g-1. Pt nanodendrites supported on the PHCSs are synthesized by polyol reduction method which exhibit high electrocatalytic activity towards methanol oxidation reaction (MOR). Moreover, Copoisoning tolerance of the Pt nanodendrites is greatly enhanced owing to the surface chemical property of the PHCSs support.Porous Pt-Cu alloy networks are synthesized through a one-pot hydrothermal process, with ethylene glycol as the reducing agent and the block copolymer Pluronic F127 as structure-directing agent. The structure, porosity and surface chemical state of as-prepared Pt-Cu alloy with different composition are characterized. The formation mechanism of the porous structure is investigated by time sequential experiments. The obtained Pt53Cu47 alloy possesses a unique 3D hierarchical porous network structure assembled by interconnected nanodendrites as building blocks. Because of the high surface area, concave surface topology and open porous structure, the Pt53Cu47 alloy catalyst exhibits enhanced catalytic activity towards methanol and ethanol electro-oxidation in comparison with commercial Pt black and the Pt73Cu27 alloy synthesized following the same process as Pt53Cu47. |
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