Morphological evolution of noble metal nanoparticles in chloroform: mechanism of switching on/off by protic species

OSCAR A. DOUGLAS GALLARDO; CÉSAR G. GOMEZ; MICAELA A. MACCHIONE; FERNANDO P. COMETTO; EDUARDO A. CORONADO; VICENTE A. MACAGNO; MANUEL A. PÉREZ

RSC Advances

The Royal Society of Chemistry

Año: 2015 vol. 5 p. 100488 - 100488

he morphological stability/morphological reshaping of noble metal nanoparticles are studied experimentally in order to unravel the chemical mechanisms lying beneath. Gold and silver nanoparticles (AuNPs and AgNPs, respectively) formed in a chloroformic environment are used, as model synthetic systems, to study the phenomena of morphological change. The morphological evolution of NPs thatfollows their formation, is characterized by spectroscopy (UV-visible, Raman and FTIR) and TEM (Transmission Electron Microscopy). The change of NP morphology involves the increase of the average NP size and the broadening of size distribution, in a close resemblance with the effect characteristicallyobtained from the Ostwald ripening. The effect of the poor solvating properties of chloroform in stabilizing small charged species (H+, Ag+, Au+) as well as the principle of electroneutrality of matter are analyzed in order to formulate a feasible reaction scheme consisting of a three-step process: the gen