小尺寸单分散铂纳米粒子的制备

Preparation of Platinum Nanoparticles with Monodisperse Small Size

为提高铂催化剂的催化活性,降低催化剂成本,在水/TX-4(壬基酚聚氧乙烯醚)/正丁醇/环己烷微乳液体系中成功制备了粒径2～4nm的单分散铂纳米粒子,并对其进行了TEM和EDS表征。微乳液体系的相图表明,Kw=5∶3,m(S-As)/m(O)=3∶2是制备小尺寸铂纳米粒子的最佳配比。H2PtCl6和NaBH4(过量时)浓度增大时,对产物粒径影响不大,但使粒径的均匀性降低;增溶水量ω增大,粒子粒径增大。CH2PtCl6≤25mmol·L-1,CNaBH4≥100mmol·L-1,ω≤2是制备小尺寸、单分散铂纳米粒子的关键,粒子尺寸可通过改变ω值调节。

In order to improve catalytic activity, decrease cost of Pt nano-catalysts, monodisperse Pt nanoparti- cles with size changed from approximately 2 nm to 4 nm were prepared successfully in water/TX-4/n-butanol/cyclo- hexane microemulsion system. Pt nanoparticles were characterized by TEM and EDS. The phase diagram of this mi- croemulsion system showed that, both Kw is 5 ： 3 and m（S-As）/m（O）= 3 ： 2 are the best conditions to preparing small size Pt nanoparticles. Various effect factors on Pt nanoparticles were also investigated. The results revealed that the effect of H2 PtCl0 and NaBH4 （when excessive） concentration to particle size is negligible, but the particle size dis- tribution broadened. The particle size increased along with the increase of distilled water w. It is the key to control the concentration of H2 PtCI6 no more than 25 mmol· L^-1 , the concentration of NaBH4 no less than 100 mmol· L^-1 and co no more than 2 to obtaining Pt nanoparticles with monodisperse small size. The particle size can be adjusted by chaning ωvalues.