Abstract:Gold nanoparticles with different shapes were prepared and used as catalysts in the reduction of p-nitrophenol (PNP) in the aqueous phase and in the presence of sodium borohydride (NaBH 4 ). Parameters such as the reaction temperature, substrate/NaBH 4 molar ratio, and substrate/gold molar ratio were tested and evaluated. In this paper, we compare the catalytic reactivities of gold nanorods (AuNRs) and gold nanospheres (AuNSs), both synthesized by the seed-mediated method in the presence of cetyltrimethyl ammonium bromide (CTAB). Physical-chemical parameters such as the apparent rate constant (k app ) and activation energy (E a ) of the reactions were obtained for both systems. We observed that the catalytic system based on AuNRs is the most active. These colloidal dispersions were investigated and fully characterized by ultraviolet-visible absorption spectroscopy (UV-Vis) and transmission electron microscopy (TEM).
Gold nanorods with a relevant aspect ratio were synthesized in high yields and good selectivities in the presence of ammonium surfactants bearing tunable hydroxyalkylated headgroups. The role of the OH function was demonstrated and the dynamics of the growth process were investigated through UV-vis measurements.
International audienceEasily tunable N,N-dimethyl-N-alkyl-N-(hydroxyalkyl)ammonium salts have been synthesized and used as capping agents to produce size- and shape-controlled anisotropic gold nanoparticles. The influence of the lipophilic chain length and the counter-ion of this original library of hydroxylated surfactants has been evaluated. From this study, various shapes (spheres, rods, prisms) have been achieved
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