High response and selectivity toward hydrogen gas detection by In2O3 doped Pd@ZnO core-shell nanoparticles

Abstract

An efficient hydrogen gas sensor comprising 5 wt% In2O3 doped in Pd@ZnO core-shell nanoparticles (Pd@ZnO–In2O3 CSNPs) was synthesized via a facile hydrothermal approach. The obtained material has a higher Brunauer-Emmett-Teller surface area (80 m2 g−1) compared to Pd@ZnO (56 m2 g−1) and pure ZnO (40 m2 g−1). The Pd@ZnO–In2O3 sensor achieved the maximal response (42) to 100 ppm hydrogen at 300 °C. Whereas, Pd@ZnO and pure ZnO sensors exhibited lower responses (17 and 9) to 100 ppm hydrogen at a higher optimal temperature (350 °C). It also demonstrated faster response and recovery time (0.4 and 4.0 min) than those obtained from Pd@ZnO (1.4 and 14 min) and pure ZnO (6.0 and 18.0 min) sensors. The hydrogen sensing enhancement of Pd@ZnO–In2O3 materials could be largely attributed to the synergistic electronic and chemical activities of Pd, ZnO and In2O3 parts, and its large surface area. Especially, due to the ability to adsorb hydrogen of the core, Pd based sensors exhibited high selectivity to hydrogen with respect to Pd-free sensors.