| 查看: 682 | 回复: 3 | ||
| 【奖励】 本帖被评价1次，作者chl5063增加金币 0.5 个 | ||
| 当前主题已经存档。 | ||
[资源]
杨培东：一种控制纳米晶形状的新方法，Nanocubes give better shaped crystals
|
||
|
【纳米科技世界快讯】Scientists in the US have developed a new way to control the shape of metal nanocrystals – by using a small particle of a different metal as a "seed" and varying the conditions in the reaction solution. Peidong Yang of the University of California at Berkeley and colleagues started with a platinum nanocube to produce palladium nanocrystals with three different shapes. The technique could have applications in catalysis, say the researchers. Controlling the morphology of nanocrystals is important because many of their physical and chemical properties are highly shape-dependent. Most research so far has focused on heterostructures made on chalcogenide interfaces, yet controlling the shape of individual binary metallic nanoparticles has been little studied. Yang and co-workers used highly faceted cubic platinum nanocrystals as nucleation seeds to direct the overgrowth of a lattice-matched palladium-based compound in solution. The platinum cubes measured around 13 nm along each face and have only <100> surface planes. The Pd undergoes conformal growth on the surface of these seeds to produce Pt/Pd bimetallic core-shell structures. Depending on the reaction environment, which contains nitrogen dioxide, the team obtained three different shapes – cubes, cuboctahedra and octahedra – with different types of surfaces. These were (100) surface planes for cubes, (111) surfaces for octahedra and mixed surface for cuboctahedra. The researchers were able to observe these structures using electron microscopy (see figure). They say that the amount of nitrogen dioxide in the reaction system is responsible for the final shape of the nanocrystals because it regulates the growth rate of the Pd along its <100> and <111> planes. In contrast, when no seeds were used no shape control was seen, just a mixture of large particles including non-polyhedral particles, rods and various faceted particles. According to the team, this means that the cubic Pt seeds serve two purposes: providing a well-defined surface for the overgrowth of the secondary metal and dictating the final shape of the core-shell heterostructures. Such shape control enables the production of nanocrystals with specific shapes and surface types," Yang told nanotechweb.org. "It could therefore allow catalytic reactions with great selectivity." The researchers say that their technique could be applied to other material systems, for example ruthenium, iron-platinum and cobalt-platinum. These novel heterostructures could be used for catalysis, as well as optical and magnetic applications, where shape control plays a crucial role. The work was published in Nature Materials |
回复此楼» 猜你喜欢
武汉纺织大学化工学院官方群-院士团队招生-学生自由度高-10余名学生赴985海外深造
已经有0人回复
-
南昌航空大学蒋华麟教授课题组招收化学、环境、碳达峰碳中和及相关专业硕士信息
已经有0人回复
-
金属材料论文润色/翻译怎么收费?
已经有130人回复
-
湖北师范大学复试调剂
已经有0人回复
-
武汉纺织大学_化工学院官方调剂群-院士团队招生-学生自由度高-每届发展好
已经有0人回复
-
济南大学国家优青课题组 2026 调剂招生来啦
已经有0人回复
-
武汉纺织大学_化学院官方调剂群-院士团队招生-学生自由度高发展好-欢迎各位同学
已经有0人回复
-
河北大学 材料与化工 硕士招收调剂
已经有0人回复
» 本主题相关商家推荐: (我也要在这里推广)
2楼2007-07-22 18:25:00
3楼2007-07-22 19:59:09
4楼2007-07-23 14:38:04
