Electrochemical and in Situ SERS Studies on the Adsorption of 2-Hydroxypyridine and Polyethyleneimine during Silver Electroplating

摘要

In this paper, 2-hydroxypyridine (2-HP) and polyethyleneimine (PEI) were selected as ligand and additive, respectively, in a cyanide-free silver electroplating bath. Adsorption behaviors of 2-HP and PEI at silver electrodes were investigated by means of potential-dependent surface-enhanced Raman spectroscopy (SERS). The adsorption configuration variations of 2-HP and PEI at the silver surface with the negative shift of potential were discussed according to the SERS analysis. The possible effect of 2-HP and PEI on the silver electroplating process was also proposed. In the silver electroplating process, the SERS signal variations of 2-HP with the negative shift of potential were mainly due to the deposits' morphology change. In the presence of PEI, fine grains and smoother surfaces are observed from the images of atomic force microscopy of the silver deposits.