Bioinspired Fern-like Fe₂O₃ Functionalized with Pd/PdO Nanoparticles for High-Performance Acetone Sensing

The accurate monitoring and detection of acetone vapor are essential for environmental and human safety. Consequently, fern-like Fe₂O₃ with hierarchical vein-like structures is synthesized via a concise hydrothermal method. Compared with pure fern-like Fe₂O₃, fern-like Pd/PdO-Fe₂O₃ shows the best acetone-sensing characteristics, in terms of lower operating temperature (180 °C), better selectivity and excellent long-term stability. More importantly, the response value of the Pd/PdO-Fe₂O₃ sensor to 100 ppm acetone reaches as high as 73, which is 55% higher than that of pristine fern-like Fe₂O₃. This enhanced sensing performance can be ascribed to the synergistic effect between Pd/PdO and fern-like Fe₂O₃. On the one hand, Pd/PdO nanoparticles show favorable catalytic activity toward ionized oxygen molecules; meanwhile, the formation of the heterojunction between PdO and fern-like Fe₂O₃ plays an important role. On the other hand, the hierarchical nature of fern-like Fe₂O₃ promotes efficient gas diffusion throughout the structure. Based on its advantages, fern-like Pd/PdO-Fe₂O₃ becomes a satisfactory candidate for acetone gas sensors.