Sánchez-Ramírez J F, Jiménez Pérez J L, Cruz Orea A, Gutierrez Fuentes R, Bautista-Hernández A, Pal U
CICATA-IPN, Legaría 694, Col. Irrigación, 11500 México D F, Mexico.
J Nanosci Nanotechnol. 2006 Mar;6(3):685-90. doi: 10.1166/jnn.2006.124.
Colloidal suspensions of bimetallic Au/Pd nanoparticles were prepared by simultaneous reduction of the metal ions from their corresponding chloride salts with polymer (PVP) stabilizer. Thermal properties of water containing bimetallic nanoparticles with different nominal compositions (Au/Pd = 12/1, 5/1, 1/1, 1/5) were measured using the mode mismatched dual-beam thermal lens technique to determine the effect of particle composition on the thermal diffusivity of the nanofluids. The characteristic time constant of the transient thermal lens was estimated by fitting the experimental data to the theoretical expression for transient thermal lens. The thermal diffusivity of the nanofluids (water, containing Au/Pd bimetallic nanoparticles) is seen to be strongly dependent on the composition of the particles. The maximum diffusivity was achieved for the nanoparticles with highest Au/Pd molar ratio. A possible mechanism for such high thermal diffusivity of the nanofluids with bimetallic particles is given. UV-Vis spectroscopy, TEM and high-resolution electron microscopy (HREM) techniques were used to characterize the Au/Pd bimetallic nanoparticles.
通过用聚合物（PVP）稳定剂同时还原相应氯化物盐中的金属离子，制备了双金属Au/Pd纳米颗粒的胶体悬浮液。使用模式失配双光束热透镜技术测量了含有不同标称组成（Au/Pd = 12/1、5/1、1/1、1/5）的双金属纳米颗粒的水的热性质，以确定颗粒组成对纳米流体热扩散率的影响。通过将实验数据拟合到瞬态热透镜的理论表达式，估算了瞬态热透镜的特征时间常数。可以看出，纳米流体（含有Au/Pd双金属纳米颗粒的水）的热扩散率强烈依赖于颗粒的组成。对于具有最高Au/Pd摩尔比的纳米颗粒，实现了最大扩散率。给出了具有双金属颗粒的纳米流体具有这种高热扩散率的可能机制。使用紫外-可见光谱、透射电子显微镜和高分辨率电子显微镜（HREM）技术对Au/Pd双金属纳米颗粒进行了表征。
