尺寸比例可调的Au-Ni双金属纳米颗粒的制备

本文采用贵金属诱导还原法制备了一种Ni端尺寸可调的Au-Ni双金属纳米颗粒.该反应以十八胺为还原剂,硝酸镍和氯金酸为反应物,反应中Au3+首先被还原成Au0,随着温度上升,Ni2+从Au0获得电子而被还原成Ni0,十八胺持续提供电子,得到了雪人状的Au-Ni双金属纳米颗粒.采用I2/KI水溶液和0.5%(质量分数)盐酸分别对Au端和Ni端进行择性蚀刻,通过调节蚀刻时间,连续调控两端尺寸,可以达到完全刻蚀,最终制备了一种两端尺寸比例连续可调的Au-Ni双金属纳米颗粒.蚀刻后得到的新鲜表面为进一步功能复合提供了反应场所.

Synthesis of Au-Ni Bimetallic Nanoparticles with Tunable Aspect Ratio

In this paper, the Au-Ni bimetallic nanoparticles with tunable aspect ratio of Au to Ni were synthe-sized by noble-metal-induced-reduction strategy. Octadecylamine is reducible at high temperatures thus it was used as a reducing agent. As the temperature increased gradually, Au3+was reduced by octadecylamine to form Au0 . After that, Ni2+ was reduced to Ni0 by obtaining electrons from Au0 at 220 ℃. Octadecylamine provided electrons to Au3+ continuously during the reaction. The size of Ni side could be tunable by changing the reaction time at 220 ℃. Au side and Ni side could be selectively etched with aqueous I2/KI and 0. 5%( mass fraction) aqueous HCl, respectively. The size of Au-Ni bimetallic nanoparticles could be tuned continuously by etching for varied time. Au side or Ni side could be completely etched separately, remaining Ni nanoparticles or Au nanoparticles. The fresh surface obtained after etching Au side or Ni side provided a site of chemical reaction for further compositing functional substances. This method is attractive owing to the easiness to continuously tuning aspect ratio of the bimetallic nanoparticles. On the other hand, composition of the bimetallic nanoparticles is also flexibly tunable using different reactants.