A Self-Powered Photoelectrochemical and Non-Enzymatic Glucose Sensor Based on ERGO/ZnONWs/CdS Photoanode

Abstract

We have developed an efficient, self-powered, non-enzymatic photoelectrochemical (PEC) glucose sensor operating in the visible spectrum. The sensor is based on electrochemically reduced graphene oxide (ERGO) and zinc oxide (ZnO) nanowalls (NWs) decorated with cadmium sulfide (CdS) quantum dots (QDs). We used a one-pot electrochemical process to grow vertically aligned ZnONWs on ERGO, followed by using the sequential ionic layer adsorption and reaction (SILAR) technique to decorate the ZnONWs with CdS QDs. The resulting ERGO/ZnONWs/CdS photoelectrode exhibits a three-dimensional hierarchical morphology, providing a large surface area for enhanced surface-substrate interactions and increased optical path length, leading to high absorptivity at visible light. Under one solar light illumination without a bias voltage, the electrode generated a significantly higher photocurrent density (1150 µAcm-2) in the presence of glucose (15.00 mM) than in the absence of glucose (150 µAcm-2). As a PEC glucose sensor, the ERGO/ZnONWs/CdS photoelectrode demonstrated two linear correlations in the glucose concentration range of 0.01–1.00 mM and 1.00–15.00 mM. The sensor has 430.06 and 25.75 µA cm-2mM-1 sensitivities and a low detection limit (1.1 μM). This novel visible light-mediated self-powered electrochemical sensing platform is cost-effective, reproducible, and stable for non-enzymatic glucose detection.