A CdxZn1−xS/TiO2 nanotube array electrode for a highly sensitive and selective nonenzymatic photoelectrochemical glucose sensor

Abstract

Enzyme-free glucose sensors have attracted remarkable attention rather than enzyme-based glucose biosensors due to their high stability, reproducibility and low price. In this work, a nonenzymatic glucose sensor based on Cd_xZn_1−xS nanofilms on TiO₂ nanotube arrays (Cd_xZn_1−xS/TiO₂ NTAs) has been fabricated. The morphology of the electrode was examined by TEM and SEM techniques. Elemental mapping, XPS analysis, the XRD technique, and the EDS method were employed to investigate the crystal phase and the presence of elements in the composition. The modified electrode has an outstanding photocurrent response with an increase of almost four times compared to TiO₂ NTAs. This Cd_xZn_1−xS/TiO₂ NTAs heterostructure possesses superior sensing properties with high sensitivity of 1331.7 μA mM⁻¹.cm⁻², a linear range of 0–214 μM, and a detection limit of 0.225 μM at a signal-to-noise ratio of 3. Discrete architectures comprising Cd_xZn_1−xS immobilized on a TiO₂ nanotube array substrate significantly improved the sensor's stability and reusability. Additionally, this cost-effective modified sensor was successfully applied for screening glucose in real plasma samples.