Formación de aleación en la síntesis electroquímica de nanopartículas bimetálicas de cadmio y plata

RUBÉN E. AMBRUSI; SILVANA G. GARCÍA

Santa Fe

Simposio; XIII Simposio Materia- 14° SAM-CONAMET; 2014

Universidad Nacional del Litoral

In the present work, the formation of bimetallic Cd-Ag nanoparticles on vitreous carbon (VC) and the involved alloy formation have been studied by conventional electrochemical techniques. Both metals were deposited by sequential electrodeposition using single potentiostatic pulses. The Ag deposits were characterized by ex-situ Atomic Force Microscopy (AFM). The AFM images of these deposits showed small differently sized Ag nanocrystallites uniformly distributed over the VC substrate. This modified substrate was immersed in an electrolyte solution containing Cd2+ ions and the preparation of bimetallic Cd-Ag particles were performed by Cd underpotential deposition (UPD) on Ag. The alloy formation phenomena observed previously during Cd UPD on massive Ag electrodes were found also in the case of Cd UPD on Ag nanoparticles. The desorption spectra in the system Cd/Ag (nanoparticles)/VC employing different polarization times, showed three desorption peaks associated with the dissolution of the Cd deposits generated by overpotential deposition (OPD) and UPD and an Ag-Cd alloy formed at low underpotentials, respectively. Other polarization routine was designed in order to understand better the electrochemical behavior of the bimetallic system.