Unusual Stability and Catalytic Activity of Gold Nanoparticles in Polyoxyethylene Cholesteryl Ether

摘要

We report a simple and spontaneous method for creation of extremely stable and catalytically active gold nanoparticles (AuNPs) from polyoxyethylene cholesteryl ether (ChEO(15)) and sodium tetrachloroaurate (III) dihydrate (Na[AuCl4] center dot 2H(2)O). AuNPs with uniform size and distribution were prepared at 27 degrees C (AuNPs were formed in <3 h) and at 50 degrees C (AuNPs were formed in <1 h). Our elucidations propose that creation of well-defined AuNPs is assisted by reductive ChEO(15) surfactant solution via complexation and in-situ reduction of AuCl4- ions in which ChEO(15) acts both as a reducing and consequently a stabilizing (capping) moiety. AuNPs size can be altered by suitably choosing the Au precursor concentration. The resulting AuNPs reveal outstanding catalytic activity for conversion of nitrophenols to aminophenol in the presence of NaBH4 and also exhibit synthetic peroxidase-like activity. This simple yet effective synthesis technique opens prospect for creation of stable and active AuNPs.