Abstract: Platinum hollow nanospheres(Pt_Hollow) were prepared in batch at room temperature by using selenium nanospheres as template,chloroplatinic acid precursor,ascorbic acid as reducing agent and SDSN as stabilizing agent,and the prepared platinum hollow spheres were used to modify glassy carbon electrode(Pt_Hollow/GC).In addition,electro-deposition platinum nanoparticles modified glassy carbon electrode(Pt_nano/GC) was prepared for comparison.The morphology and structure were characterized with X-ray diffraction,scanning electron microscopy and transmission electron microscope.Platinum hollow nanospheres had excellent dispersion and uniform size,and the diameter was about 120 nm.The shell was porous with a thickness smaller than 10 nm and was constructed by multi-dimensional and multi-level Pt atoms clusters.Formaldehyde was used as probe molecules,and the conventional electrochemical methods,including cyclic voltammetry and chronoamperometry curves were used to test the catalytic performance of Pt_Hollow/GC and Pt_nano/GC towards formaldehyde oxidation under the same electrical activity area condition.Current density at 0.64 V of Pt_Hollow/GC was 1.5 times of that of Pt_nano/GC.Oxidation potential at 0.5 mA穋m^-2 current density of the former was more negative than the latter by about 30 mV.The experimental evidence indicated that compared with Pt_nano/GC electrode,formaldehyde oxidation on Pt_Hollow/GC electrode had lower activation energy,faster reaction speed and higher catalytic activity.These could provide experimental and theoretical basis for the preparation of anode catalyst in direct formaldehyde fuel cells.

Key words: selenium template, Pt hollow nanosphere, cyclic voltammetry, chronoamperometry

摘要： 以纳米硒球为模板,H₂PtCl₆为前驱体,以抗环血酸为还原剂,SDSN作稳定剂,在室温下批量制备了铂纳米空球(Pt_Hollow)及其修饰玻碳(GC)电极(Pt_Hollow/GC)。使用XRD、SEM和TEM等检测技术表征了其形貌与结构,结果表明,所制备的铂纳米空球分散性好,粒径比较均匀,约为120 nm;球壳多孔,壳厚<10 nm,由多维、多级的多晶铂原子团簇所构建。以甲醛为探针分子,采用循环伏安及计时电流等常规电化学方法比较了电活性面积基本一致的Pt_Hollow/GC和电沉积铂纳米粒子(Pt_nano)修饰GC电极(Pt_nano/GC)催化甲醛氧化的性能,结果显示,位于0.64 V处的氧化峰电流密度,前者是后者氧化峰电流密度的1.5倍;氧化电流密度为0.5 mA·cm^-2处的氧化电位,前者比后者负移了约30 mV。实验结果表明,与Pt_nano/GC电极相比,甲醛在Pt_Hollow/GC电极上氧化的活化能低,反应速度快,催化活性高。所得结果为直接甲醛燃料电池阳极催化剂的研制提供了一定的实验与理论依据。

关键词: 硒模板, 铂纳米空球, 循环伏安, 计时电流