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

• Published in: Sensors and actuators. B, Chemical Vol. 297; p. 126693
• Main Authors: Kim, Jae-Hun, Mirzaei, Ali, Kim, Hyoun Woo, Kim, Sang Sub
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-10-2019; Elsevier Science Ltd
• Subjects: Detection; Gas sensor; Gas sensors; Hydrogen; Hydrogen gas; Metallizing; Nanoparticles; Nanowires; Palladium; Pd functionalization; Selectivity; Sensitivity enhancement; Ultraviolet radiation; Zinc oxide; ZnO nanowire; ZnO nanowire; Gas sensor; Pd functionalization; Hydrogen gas
• ISSN: 0925-4005; 1873-3077
• DOI: 10.1016/j.snb.2019.126693

•Pd-functionalization enhanced hydrogen sensing capability of ZnO nanowires (NWs).•Pd-functionalized ZnO NWs exhibited a bell-shaped dependence on temperature.•Pd-functionalized ZnO NWs gas sensor showed a high selectivity to hydrogen gas.•Superior hydrogen sensing was related to Pd nanoparticles, metallization effect of ZnO, and partial conversion of Pd to PdHx.
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.