Ag nanoparticles-decorated ZnO nanorods for the selective electrochemical detection of Pb ion in water surface

The pollution of lead (Pb) in aquatic environments is still harmful to human health, leading to the necessity of creating sensitive, selective, and scalable detection technologies. In this work, an electrochemical sensing platform based on morphology-controlled AgNP/ZnONR/ITO heterointerface was fabricated to be used in square wave anodic stripping voltammetry (SWASV). What is novel about the current study is that ZnONR have not previously been used in isolation with Ag nanoparticles (AgNP) as a conventional sensing material, but rational integration of vertically aligned ZnONR grown directly on indium tin oxide (ITO) as a high-surface-area, direct electron-transport scaffold with subsequent AgNP decoration to form constructive areas of conductivity and electroactivity that favour favourable Moreover, AgNP functionalisation was realised with the help of a salt reduction approach, which involved the use of extract of Gymnanthemum amygdalinum (Beijing grass) as a biogenic reductant to offer a straightforward and more sustainable method of nanostructure modification. The hydrothermal method at a low temperature has been used to fabricate ZnONR with rod diameters ranging from 80 to 95 nm. ZnONR surfaces were decorated with AgNP (approximately 23 nm) to facilitate enhanced charge transfer dynamics at the electrode-electrolyte interface. The electrochemical performance of the modified electrode was assessed utilising square wave anodic stripping voltammetry (SWASV) and cyclic voltammetry (CV), and exhibited outstanding sensitivity (6.86 μA cm− 2 μM- 1 ), low detection limit (0.02 μM), and a linear response within the range of 0.4–3.0 μM for Pb ion. Moreover, application to real seawater samples showed reliable detection, indicating its applicability for on-site monitoring for trace Pb contamination, thereby providing a scalable and technologically significant solution to the ongoing challenge of lead pollution in aquatic environments.