The need to reduce and eliminate exposure to the toxic contaminant lead (Pb) from drinking water calls for advances in cheap and low-footprint sensing technologies such as stripping voltammetry. This study examines the performance of laser-induced graphene (LIG) electrodes from polyimide (PI) and polyethersulfone (PES) precursors in anodic stripping voltammetry of Pb(II). Despite their similar electrochemical properties and conductivity, as characterized by electrochemical impedance spectroscopy and two-point conductivity, respectively, subtle differences in physical and chemical properties, as measured by scanning electron microscopy and X-ray photoelectron spectroscopy, respectively, lead to PI-LIG electrodes exhibiting higher sensitivity than PES-LIG electrodes. Enhanced electrochemical activity of the PES-LIG electrodes for side reactions due to sulfur substitutions could potentially account for the difference in performance. The results of this study highlight that the starting material can heavily determine the performance of electrodes formed via laser-induced graphitization for sensing and other electrochemical applications.
Keywords: anodic stripping voltammetry; laser-induced graphene; lead; polyethersulfone; polyimide; sensing; water quality.