Main Article Content
The effects of ultrasonic irradiation time on the palladium nanoparticles (Pdns) formation mechanism have been investigated using UV-Visible spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Pdns colloids have been prepared by ultrasonic irradiation of Pd(NO3)2 solutions at different irradiation times (from 30 to 180 minutes). The obtained results show that the rate of sonochemical reduction of Pd(II) ions has been found to be dependent upon the irradiation time. The kinetic of Pdns formation can also be correlated with the rate of sonochemical reduction ofPd(II) ions, as well as with the role of PVP molecules. The results suggest a three-step mechanism to describe the Pdns formation as a function of ultrasound irradiation time. During the first step, the Pd(II) ions are rapidly reduced to Pd(0) atoms, and when the concentration of Pd(0) atoms is sufficient for nucleation, the formation of primary particles occurs which are stabilised by a maximal number of PVP molecules. During the second step, these particles grow progressively by adsorption of the Pd(0) atoms and the obtained particles are coordinated to all available PVP molecules. The third step corresponds to decrease of the bounded PVP to the particle surface and the growth of the large particles at the expense of the unstable small ones.
Keywords: Palladium nanoparticles, ultrasound irradiation, formation mechanism, UV-visible spectroscopy, FT-IR spectroscopy, TEM.
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).