Mechanism of Preparing Spherical Nano-sized Silver Particles via o-Phenylenediamine Reduction Process in Water-NMPD Mixed Solution System

At room temperature, silver nano-sized particles were one-step prepared by a novel facile method of the reduction of silver nitrate with o-Phenylenediamine (o-PD) in a mixed solution of water and N-Methyl-2-pyrrolidone(NMPD). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed to characterize as-prepared silver nanoparticles. The SEM images show that silver nano-particles are well spherical and possessed of uniform particle size, and the average particle size is about 70 nm. The XRD pattern indicates that the values of dhkl, a, and unit cell volume (V3) of Ag crystal are all a little greater than that of Ag standard card, with face-centred cubic structure. UV-visible spectra (UV-Vs) and liquid chromatography-mass spectrometry (LC-MS) was used to identify the product of oxidation of o-PD in solution after reaction. The results of UV-Vs and LC-MS illustrate that the product of oxidation of o-PD in solution is 2,3-diaminophenazine.