Electrodeposition of Vertically Aligned Silver Nanoplate Arrays on Indium Tin Oxide Substrates

Vertically aligned Ag nanoplates (NPs) were fabricated on indium tin oxide (ITO) substrates by electrodeposition growth in the AgNO₃ solution using citrate anions as the shape-controlling agent. The factors affecting the deposition process, such as the potentials applied to the ITO substrate and the concentration of the precursors and citrate, were systematically investigated. We found that the potentials applied both for nucleus generation and for nucleus growth play important roles in tuning the morphology of the Ag NPs. It was also found that the concentration ratio of capping agent to precursor (R) is a critical factor; only when R is relatively low (R < 1.0) could the well-aligned Ag NPs be formed. However, a high R value will lead to the isotropic growth of the Ag crystal. A concentration-gradient-induced growth mechanism of vertically aligned Ag NPs is proposed on the basis of experimental results obtained. A Ag NPs/Ag₃PO₄ composite electrode was fabricated by a electrodeposition method. The photoelectrochemical oxygen evolution reaction activity of the Ag NPs/Ag₃PO₄ electrode is about 15.6 times higher than that of a control electrode, which was fabricated on the basis of a Ag electrode whose morphology was irregular polyhedrons.