Title of article :
Synthesis of gold nanorods using concentrated aerosol OT in hexane and its application as catalyst for the reduction of eosin
Author/Authors :
Srivastava، نويسنده , , Shruti and Sharma، نويسنده , , Surender Kumar and Sharma، نويسنده , , Rakesh Kumar، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2011
Abstract :
The microemulsion method for the preparation of nanoparticles is well known. We have used the aqueous core of highly concentrated aerosol OT in hexane solution to synthesize gold nanorod by utilizing the aqueous core of surfactant aggregates as host nanoreactor. The shape and size of the aqueous core as well as the particles formed inside the core can be controlled by changing the parameter W0 (water to surfactant ratio), concentration of gold salt and the concentration of surfactant. When the concentration of the surfactant is very high the shape of the aqueous droplet does not remain spherical but take the shape of prolate. In our study we have made gold nanorods by the reduction of gold chloride with sodium borohydride in the aqueous core of 1 M AOT hexane at a W0 of 10. The rods are highly monodispersed with a diameter of about 20 nm and a length of 200 nm with an aspect ratio of 10. The absorption spectra of the gold nanorods show two different peaks one at 535 nm and the other at 965 nm. The particles were used as a catalyst for the reduction of eosin with sodium borohydride. The rate constant comes out be very large in comparison with that of uncatalysed reaction. The reaction was carried out at various temperatures between 20 and 60 °C and the activation energy of the reaction was calculated using Arrhenius plot between–ln k and 1/T. The activation energy of the gold nanorods catalysed reaction comes out to be more than two times as compared to uncatalysed reaction.
Keywords :
nanorods , Surfactant aggregates , microemulsions , Eosin
Journal title :
Colloids and Surfaces A Physicochemical and Engineering Aspects
Journal title :
Colloids and Surfaces A Physicochemical and Engineering Aspects