Abstract
Underpotential (UPD) and overpotential (OPD) deposition of Pb from a perchlorate solution on gold substrate was studied using in-situ electrochemical quartz crystal microbalance (EQCM) method. Cyclic voltammograms and current-transients recorded during potentiostatic electrochemical deposition were measured simultaneously with EQCM data including frequency and resistance. Results show that underpotential deposition (UPD) of Pb occurs before overpotential deposition (OPD) of Pb starts to grow, based on both massogram and cyclic voltammogram. The OPD of Pb grows at higher overpotentials which significantly influence the mechanism of nucleation and growth. EQCM reveals that the mass to charge ratio of OPD is different at different overpotentials, owing to the mechanism of nucleation and growth and possible roughening of grown Pb or hydrogen evolution. A comparison between our experimental data with the Scharifker-Hills theory based on non-dimensional plots shows an instantaneous mechanism. Scanning electron microscope taken from the electrodeposited lead on gold confirms the behaviour exhibiting almost same size of nuclei.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call