Investigation of Reduction Mechanism in the Borohydride-Mediated Synthesis of Silver Nanoparticles

Abstract

The silver nanoparticles have been used in various industrial applications. The conventional synthesis method is the reduction of silver(I) ion with borohydride solution, but the mechanism for this reaction has unknown. Here, the investigation of reduction mechanism of silver(I) ion by borohydride, synthesis of silver nanoparticles, was studied by ab initio and Density Functional Theory (DFT) calculation. The HF/6-31++G** and B3LYP/6-31++G** levels were used in this study. LANL2DZ an Effective Core Potential (ECP) basis set was used in the calculation of the silver(I) ion. In parts of the transition state and activation energy (Ea), the QST2 was selected as the method for calculations. Mechanism modeling was proposed in three mechanisms that was mechanism I (BH₄-Ag), mechanism II (2BH₄-Ag-) and mechanism III (BH₃OH-Ag--BH₄ ) borohydride-mediated in transition state, respectively. The results showed that the mechanism II and mechanism III modeling could display the transition state. The mechanism III exhibit less activation energy, and produces more exergonic energy than mechanism II. Therefore, the mechanism III was a reasonable pathway for the synthesis of silver nanoparticles.