Size- and shape-tunable silver nanoparticles created through facile aqueous synthesis

Abstract

Growth of silver nanoparticles (NPs) with a size ranging from of 6 ± 0.8–42 ± 1.6 nm was investigated systematically by the NaBH₄ reduction of silver nitrate using citrate and poly (vinyl pyrrolidone) (PVP) as stabilizers through a facile one-pot aqueous synthesis. Because of controlling nucleation and growth processes, the NPs revealed narrow size distribution. Citrate and NaCl play important roles for the NPs with spherical morphology because of the adsorption of C₆H₅O₇ ³⁻on the {111} facet of silver particles and the etching of Cl⁻/O₂. The addition of PVP resulted in the NPs small size and narrow size distribution. Spherical Ag NPs cannot be acquired by such one-pot reduction method in the absence of sodium citrate and NaCl, indicating the poor balance between the nucleation and growth processes in the reactions. On the basis of the results, reduction of the silver precursor (Ag⁺) was promoted with sodium citrate, attributed to the higher activity of the citrate reductant. The selective adsorption role of C₆H₅O₇ ³⁻ and PVP on the {111} plane, in addition to the stacking fault of {111} plane, led to silver atoms in the reaction solution deposited on {111} facet in the absence of NaCl, and then formed triangular silver nanoplates.