Pd functionalization on ZnO nanowires for enhanced sensitivity and selectivity to hydrogen gas

Abstract

The detection of hydrogen (H2) gas is of importance owing to its increasing use in the modern society to achieve a cleaner life environment. In this study, bare and palladium (Pd)-functionalized ZnO nanowires (NWs) were synthesized for H2 gas sensing. The ZnO NWs were fabricated by a vapor–liquid–solid technique and Pd functionalization was performed using an ultraviolet irradiation technique. Enhanced H2 gas response of the ZnO NWs was observed after Pd functionalization. Additionally, the Pd-functionalized ZnO NW gas sensor exhibited high selectivity to H2 gas. The superior hydrogen gas sensing of the Pd-functionalized ZnO NW sensor was related mainly to the sensitization of the Pd nanoparticles, metallization effect of ZnO at the sensing temperature (350 °C), and partial PdHx formation. This study demonstrates the effectiveness of the Pd functionalization on the ZnO NWs for the realization of practical hydrogen gas sensors.