Improved photoelectrochemical properties of tungsten oxide by modification with plasmonic gold nanoparticles for the non-enzymatic sensing of ethanol

Abstract

Herein, vertically aligned plate-like tungsten trioxide (VAP-WO3) sensitized with gold nanoparticles (AuNPs) is reported for the non-enzymatic photoelectrochemical (PEC) sensing of ethanol in liquors. For the fabrication of the novel ethanol sensor, AuNPs were electrodeposited onto fluorine-doped tin oxide (FTO), and, subsequently, VAP-WO3 was hydrothermally grown on the AuNPs/FTO surface. Owing to the localized surface plasmon resonance, as well as the good conductivity of the AuNPs, the efficiency of the light absorption and the photoelectron–hole separation of VAP-WO3 were much improved, resulting in a significant enhancement in the VAP-WO3/AuNPs/FTO photocurrent. Interestingly, ethanol functioned as a sacrificial agent, leading to further amplification of the PEC signal on the VAP-WO3/AuNPs/FTO electrode. Inspired by this phenomenon, a sensitive and non-enzymatic PEC platform was constructed for monitoring ethanol in the range of 1.0–1000 μM with a detection limit of 0.5 μM, which is comparable with those obtained by the enzymatic ethanol sensors. In addition, the non-enzymatic ethanol PEC sensor has an acceptable anti-interference ability, excellent stability, and good reproducibility. Finally, the as-fabricated PEC sensor was successfully applied to determine the concentration of ethanol in liquors. Thus, this study paves the way to improved PEC performance of WO3/FTO-based electrodes and provides a promising signal-on PEC platform for ethanol determination in food.