Facile synthesis of Ag-Au nano-alloys and their catalytic applications

Prior reduction of Ag+ to Ag° in the NVP dispersed in the solvent, dimethyl formamide (DMF) complex and the subsequent addition of HAuCl4 to the mixture results in the galvanic replacement reaction, wherein the Ag nanoparticles acts as a template site for effective reduction of Au3+ to Au° augmented through NVP, thereby resulting in pure single phase Ag-Au alloy nanoparticles. Single sharp LSPR peaks for various fractional mole compositions of Ag and Au were observed between 435 to 515 nm, with the absorption peak blue shifting linearly with increase in the mole fraction of Au. The structural morphology of the alloy nanostructure was confirmed using TEM. The catalytic properties of the as-synthesized Ag-Au alloy nanoparticles were studied using the reduction process of 4-Nitro-Aniline (NA) to p-phenylenediamine (p-PDA) using NaBH4. It was found that the reduction rate of 4-NitroAniline varies with the mole composition of Ag and Au in the alloy nanostructure.