Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico 87106, USA.
Phys Chem Chem Phys. 2011 Mar 21;13(11):4846-52. doi: 10.1039/c0cp01930e. Epub 2010 Dec 23.
Novel platinum nanowheels were synthesized by the reduction of aqueous platinum complex with ascorbic acid in the presence of disk-like bicelles. The platinum nanowheels possess thickened centers and flared edges that are connected by dendritic platinum nanosheets. This structural complexity can be attributed to the inhomogeneous micro-environment of the templating bicelles consisting of a central bi-layer region and a high curvature rim. The formation mechanism of the nanowheels was investigated by imaging nanostructures at different stages of the reaction. The templating bicelles were also imaged by TEM with the aid of negative staining. The variation of reaction parameters including platinum concentration, temperature, and total concentration of surfactants (CTAB + FC7) led to other types of platinum nanostructures, such as circular dendritic nanosheets with a tunable diameter and rectangular dendritic nanosheets. Interestingly, under irradiation by a TEM electron beam, the dendritic nanosheet portion of the nanowheels transforms into a metastable holey sheet. In addition, the platinum nanowheels have an electrochemical active surface area comparable to that of ETEK platinum black and thus are expected to have potential applications in catalysis.
新型铂纳米轮是通过在圆盘状双胶束存在下，用抗坏血酸还原水相铂配合物合成的。铂纳米轮具有加厚的中心和展开的边缘，由树枝状铂纳米片连接。这种结构的复杂性可以归因于模板双胶束不均匀的微环境，由中央双层区域和高曲率边缘组成。通过在反应的不同阶段对纳米结构进行成像，研究了纳米轮的形成机制。还通过 TEM 辅助负染色对模板双胶束进行了成像。反应参数（包括铂浓度、温度和表面活性剂总浓度（CTAB+FC7）的变化导致了其他类型的铂纳米结构，如具有可调直径的圆形树枝状纳米片和矩形树枝状纳米片。有趣的是，在 TEM 电子束的照射下，纳米轮的树枝状纳米片部分转变成亚稳态多孔片。此外，铂纳米轮具有与 ETEK 铂黑相当的电化学活性表面积，因此有望在催化方面具有应用潜力。
