八面体铂纳米晶的可控合成

Controlled Synthesis of Multioctahedral Pt Nanocrystals

以氯铂酸(H_2PtCl_6)为前驱体,在聚乙烯吡咯烷酮(PVP)水溶液中,加入微量氯化铁(FeCl_3),制备出了类似八面体、具有许多分支的高晶面指数铂纳米颗粒。在该反应体系中,降低铂的浓度、加入少量铂晶种和含铁物质(Fe^(3+)或者Fe^(2+))在合成多面体结构中起到重要作用。这种反应条件促使晶种沿着铂原子的角生长,从而形成多支的纳米晶。同时,通过改变添加到反应体系中的氯化铁的浓度和反应温度,可以控制该晶体的尺寸。

Highly faceted Pt nanocrystals with a large number of interconnected arms in a quasi -octa‐hedral shape were synthesized by reducing H2 PtCl6 precursor with poly(vinyl pyrrolidone) in aqueous solutions containing a trace amount of FeCl3 .The iron species (Fe3+ or Fe2+ ) play a key role in indu‐cing the formation of the multioctahedral structure by decreasing the concentration of Pt atoms and keeping a low concentration for the Pt seeds during the reaction .This condition favors the overgrowth of Pt seeds along their corners and thus the formation of multiarmed nanocrystals .Electron microsco‐py studies revealed that the multioctahedral Pt nanocrystals exhibit a large number of edge ,corner , and surface step atoms .The size of the multioctahedral Pt nanocrystals could be controlled by varying the concentration of FeCl3 added to the reaction or the reaction temperature .