Improved Polyol Syntheses of Silver Right Bipyramids and Nanorods: Camphorquinone-Mediated Morphology Control Methods

In this research, camphorquinone (CQ)-mediated one-pot polyol methods to synthesize silver right bipyramids and nanorods with high yields are developed. The key strategy of these methods is the use of CQ which is first applied to selectively stabilize Ag(100) facets through capping. As CQ stabilizes small-sized nanocrystals, including single-twinned and nanorod structures, we successfully synthesized silver right bipyramids and nanorods as the two dominant products in a CQ-mediated polyol system. Further morphology control between silver nanorods and silver right bipyramids is conducted through adjusting the poly(vinylpyrrolidone) (PVP) concentration and reaction temperature, which can improve the formation of single-twinned and fivefold twinned particles through affecting the reduction kinetics. Silver nanorods with a yield of 87% are obtained under 150 °C with a PVP/CQ/AgNO3 molar ratio of 1.2:2:1, while silver right bipyramids with a yield of 88% are obtained under 120 °C with a molar ratio of 1.6:2:1.