Synthesis and Characterization of Au-CdS Composite Thin Films for Photoelectrochemical Sensing of Hg2+ Ions

Abstract

This article presents a simple method for fabrication of Au-CdS composite thin films onto indium-tin-oxide (ITO) coated glass substrates. The method starts with electrodeposition of CdS thin films onto ITO substrates and followed by spontaneous growth of Au nanoparticles onto the CdS surface in solutions containing AuCl4- ions. X-ray diffraction (XRD) and UV-vis spectroscopy were used to investigate the Au-CdS thin films. The photoelectrochemical property and sensing for Hg2+ ions of the Au-CdS/ITO were studied. The electrode exhibits a low limit of detection of 2.5 μM and a high selectivity for Hg2+ ions, even in the presence of a large excess (1000-fold) of other metal (Na+, K+, Ca2+, Mg2+, Cd2+, Pb2+, and Zn2+) ions.