Improving the formaldehyde gas sensing performance of the ZnO/SnO 2 nanoparticles by PdO decoration

In this work, a series of PdO catalytic ZnO/SnO 2 (PdO–ZSO) nanoparticles have been synthesized by a two-step approach including a low-temperature (− 10 °C) precipitation followed by a PdO dipping process. The composition, surface morphology, and crystal structure of the as-obtained samples were characterized by multi-techniques. And the gas-sensing properties toward formaldehyde (HCHO) were evaluated. The results indicate that the PdO–ZSO nanoparticles exhibit high sensitivity (5.4) and rapid response (37 s)/recovery (87 s) to 10 ppm HCHO at 140 °C through optimizing the ratio of PdO, ZnO, and SnO 2 in nanoparticles. Comparing with the traditional SnO 2 sensor without ZnO and PdO, the sensors’ working temperature is much lower and the response–recovery speed is also improved. In addition, the specific sensing mechanism was discussed preliminarily.