有序介孔二氧化硅-碳纳米管复合材料载Pt及其电催化性能

Fabrication of Ordered Mesoporous Silica-Carbon Nanotubes Composites as Catalyst Supports for Loading with Pt Nanoparticles and Their Electrocatalytic Performance

以十六烷基三甲基溴化铵(CTAB)为结构导向剂,正硅酸乙酯(TEOS)为硅源,通过添加碳纳米管(CNTs),制备介孔二氧化硅包覆碳纳米管网状结构的复合材料(C/Si).X射线衍射(XRD)和透射电子显微镜(TEM)显示,介孔二氧化硅的孔道结构高度有序,CNTs均匀分散于二氧化硅刚性骨架中.以其为载体微波负载制备了Pt-C/Si-x纳米粒子催化剂,研究了催化剂在硫酸和甲醇溶液中电催化性能,结果表明,具有较高导电性能的复合材料保持了二氧化硅的均匀的孔道结构有利于电解液存储和质子传输,使得该催化剂显示了良好的电催化活性.其中碳纳米管添加含量为40 mg时,催化剂在H2SO4电解液中的电化学活性面积高达120.9 m2·g-1,远大于Pt/CNTs的电化学活性面积,对甲醇的催化峰电流也达80.3 mA·cm-2.预示其作为直接甲醇燃料电池催化剂载体具有良好的应用前景.

Ordered mesoporous silica-carbon nanotubes composites have been obtained using tetraethyl- orthosilicate as silicon source and cetyltrimethylammonium bromide as templating agent and subsequentlyl were used as supports for loading with platinum nanoparticles by a microwave-irradiated polyol process. X-ray diffraction （XRD） and transmission electron microscope （TEM） show that carbon nanotubes is highly dispersed into silicon oxidation substrate. Electrocatalysis tests reveal that Pt-C/Si catalysts show excellent catalytic performance, which could be due to the doped of the high electrical conductivity carbon nanotubes （CNTs） and the ordered mesoporous structure that is beneficial to electron transfers. When 40 milligram of carbon nanotubes was added to the composites, the electrochemical active surface area （EASA） of this elec- trocatalyst is 120.9 m2.·g^-1 in 0.5 mol·L^-1 H2SO4 sulotion, which is higher than Pt-CNTs electrocatalyst and the peak current of methanol oxidation is 80.3 mA·cm^-2. Thus, this composite is promising for applications in direct methanol fuel cell.