Morphology-tuned ZnO and Ag/ZnO nanostructures for photoelectrochemical water splitting and hydrogen-sensing applications

Abstract

ZnO nanorods topped by ZnO nanowire web-like structures were synthesized hydrothermally and functionalized with Ag nanoparticles via photoreduction. In addition to characterizations by XRD, SEM, and UV–vis, surface decoration effects on chemiresistive hydrogen sensing and on photoelectrochemical hydrogen production were investigated. The samples exhibited stable and excellent detection for hydrogen at 150 °C temperature over the range from 500 to 25 000 ppm. Ag nanodecoration enhanced the sensor sensitivity significantly, especially at lower hydrogen concentrations. The performance of samples utilized as photoanodes in photoelectrochemical water splitting under AM 1.5G irradiation was evaluated. For the Ag/ZnO sample, a significantly higher photocurrent (0.20 mA/cm2) was achieved compared to the ZnO sample (0.15 mA/cm2), which was attributed to extended visible light absorption of the Ag/ZnO sample. Additionally, the samples exhibited bactericidal efficacy greater than 99.99 % against both gram-positive and gram-negative bacteria, preventing the electrodes and sensors from biological poisoning in any intended application. © 2025 Hydrogen Energy Publications LLC