Synthesis and gas sensing properties of palladium-doped indium oxide microstructures for enhanced hydrogen detection

In this paper, the pure In2O3 and Pd-doped In2O3 (0.5, 1.0, 2.0 and 4.0 mol%) flower-like spherical microstructures have been synthesized by a hydrothermal method. The crystal structure and surface morphology of as-prepared samples were characterized by X-ray diffraction and scanning electron microscopy. The gas sensing experiments were carried out on all the as-prepared gas sensors to hydrogen gas, and the measured results demonstrated that the Pd-doped In2O3 gas sensors exhibit enhanced gas sensing performance under the optimal working temperature of 210 °C. Especially, the 1.0 mol% Pd-doped In2O3 sensor shows the highest response to 100 ppm hydrogen gas at 210 °C, which was almost two times higher than that of pure one. Furthermore, the 1.0 mol% Pd-doped In2O3 gas sensor also shows fast response/recovery time about 4 and 7 s, respectively. Finally, the gas sensing mechanism was also discussed on the pure and Pd-doped In2O3 gas sensors.