Ternary heterojunctions synthesis and sensing mechanism of Pd/ZnO–SnO2 hollow nanofibers with enhanced H2 gas sensing properties

In this paper, Pd/ZnO–SnO 2 hollow nanofibers prepared by electrospinning and magnetron sputtering . The sensing materials exhibited extraordinary hydrogen (H 2 ) sensing behavior – the response reached 171 at 270 °C, and besides, the response time and recovery time were as low as 19 s and less than 1 s at 240 °C, with steady high selectivity and good repeatability. Such an enhanced sensing performance could be attributed to the Pd/ZnO/SnO 2 ternary heterojunctions formed in the hollow nanofibers. Moreover, the materials were studied by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and especially the morphology formation process was further explained. The existence of Pd was confirmed to increase the resistance modulation range of heterojunction. In addition, the gas sensing mechanism based on the structure was proposed.