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

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 degrees 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.