Pulsed current electrodeposition of Zn-Ag2S/TiO2 nanocomposite films as potential photoelectrodes

Abstract

Nanocomposite Zn-Ag2S/TiO2 and Zn-TiO2 films were prepared by pulsed current electrolysis from acidic zinc sulphate solutions on a titanium substrate. The influence of the nanoparticles' nature on the structural and morphological characteristics of the metallic electrodeposit was also investigated. The electrodeposits were characterized by X-ray diffraction and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. Using transmission electron microscopy, it was possible to conclude that the chemical treatment applied to the commercial TiO2 particles promotes the formation of Ag2S/TiO2 composite nanoparticles, with Ti, Ag, S and O in its composition. This was also was confirmed by X-ray fluorescence spectrometry. These particles absorb visible light radiation which makes them promising materials for photoelectrocatalytic processes. Moreover, the modification in nanoparticle composition plays a remarkable influence on the coating morphology and Zn crystallite size. When TiO2 is added, a change of Zn texture was observed along with a decrease in crystallite size. In contrast, the metal matrix nanocomposites prepared with Ag2S/TiO2 exhibit a spongy Zn morphology with a lower average Zn crystallite size. The nanocomposite films were tested in the photoelectrodegradation of ibuprofen and the best results were obtained for Zn-Ag2S/ TiO2 photoelectrodes.