Melvin Ambrose A, Joshi Vrushali S, Poudyal Durgasha C, Khushalani Deepa, Haram Santosh K
†Department of Chemistry, Savitribai Phule Pune University, (Formerly, University of Pune), Ganeshkhind, Pune 411007, India.
‡Materials Chemistry Group, Department of Chemical Sciences, Tata Institute of Fundamental Research, Homi Bhabha Road, Navy Nagar, Mumbai 400 005, India.
ACS Appl Mater Interfaces. 2015 Apr 1;7(12):6590-5. doi: 10.1021/am508830h. Epub 2015 Mar 18.
Electrocatalytic oxidation of methanol on silica hollow spheres, loaded with platinum nanoparticles (Pt-SiO2-HS), is reported. The functionalized hollow silica spheres were prepared by the surfactant (lauryl ester of tyrosine) template-assisted synthesis. These spheres were loaded with platinum nanoparticles by γ-radiolysis. Energy-dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS) analyses confirmed presence of Si and Pt in the composite. High-resolution transmission electron microscopy showed the formation of uniformly deposited Pt nanoparticles over the hollow spheres with a predominant Pt(111) lattice plane on the surface. In spite of the poor conducting nature of the silica support, the oxidation potential and current density per unit mass for methanol oxidation were noted to be ca. 0.72 V vs NHE and 270 mA mg(-1), respectively, which are among the best values reported in its class. The composite did not show any sign of a degradation even after repeated use. In fact, the anodic current was found to increase under constant polarization, which is attributed to a facile reaction between adsorbed CO with a surface hydroxyl group present on the silica support. These results are in favor of Pt-SiO2-HS as a promising electrocatalyst material in the direct methanol fuel cell (DMFC) applications.
据报道，负载铂纳米颗粒的二氧化硅空心球（Pt-SiO₂-HS）对甲醇具有电催化氧化作用。功能化空心二氧化硅球通过表面活性剂（酪氨酸月桂酯）模板辅助合成制备。这些球通过γ辐射分解负载铂纳米颗粒。能量色散X射线分析（EDAX）和X射线光电子能谱（XPS）分析证实了复合材料中存在硅和铂。高分辨率透射电子显微镜显示，在空心球上形成了均匀沉积的铂纳米颗粒，表面以Pt(111)晶格面为主。尽管二氧化硅载体的导电性能较差，但甲醇氧化的氧化电位和单位质量的电流密度分别约为0.72 V（相对于标准氢电极）和270 mA mg⁻¹，这是该类报道中的最佳值之一。即使重复使用后，该复合材料也没有显示出任何降解迹象。事实上，发现在恒定极化下阳极电流会增加，这归因于吸附的CO与二氧化硅载体表面存在的羟基之间的 facile 反应。这些结果表明Pt-SiO₂-HS作为直接甲醇燃料电池（DMFC）应用中有前景的电催化材料是有利的。 （注：“facile”此处可能有误，未准确翻译，推测为“容易的、便捷的”之类含义，但按要求未加解释。）
