Ultrafast response and recovery in advanced H2 sensing: Self-assembled fruit-leaf-like PdO/WO3 nanostructures

Abstract

As hydrogen is widely used as a clean energy source, the hazards of its flammable and explosive properties are gradually emphasized. Therefore, it is imminent to develop a hydrogen sensor with high response, fast detection speed and low detection limit. In this paper, a PdO/WO₃ composite with fruit-leaf-like structure was synthesized by in-situ hydrothermal and self-assembly impregnation method, and its H₂ sensing performance was investigated. The results show that the self-assembled loading of PdO can greatly improve the H₂ sensing performance of WO₃, in which the PdO/WO₃-1 sensor exhibits a very high response value (338.7) and a very short response/recovery time (1 s/4 s) at 120°C to 100 ppm H₂. The enhanced sensor performance is mainly due to the catalytic effect of the noble metal PdO on H₂ and the synergistic effect between WO₃ and PdO. The growth rhythm of PdO nanoparticles and the effect on the H₂ sensing performance of PdO/WO₃ composites were also explained by varying the concentration of PdCl₂ solution. The density functional theory calculation proves that the hydrogen sensing performance is improved after the combination of PdO and WO₃. This study provides a feasible solution for the development of high-performance WO₃-based H₂ sensors.