Nonaqueous Synthesis of Pd/PdO-Functionalized NiFe2O4 Nanoparticles Enabled Enhancing n-Butanol Detection

The efficient detection of n-butanol, which is in demand for highly sensitive materials, is essential for multiple applications. A nonaqueous method was applied to prepare NiFe2O4 nanoparticles (NPs) using benzyl alcohol as a solvent, which shows a size of 7.9 ± 1.6 nm and a large surface area of 82.23 m2/g. To further improve the sensing performance for n-butanol, Pd/PdO functionalization was sensitized with NiFe2O4 NPs. Gas sensing results demonstrate that the Pd/PdO-NiFe2O4 exhibits an enhanced response of 36.9 to 300 ppm n-butanol and a fast response and recovery time (18.2/17.6 s) at 260 °C. Furthermore, the Pd/PdO-NiFe2O4-based sensor possesses a good linear relationship between responses and the n-butanol concentration from 1 to 1000 ppm, and great selectivity against other volatile organic compounds (VOCs). The excellent sensing enhancement is attributed to the catalytic effects of Pd/PdO, the increase of oxygen vacancies, and the formation of heterojunction between PdO and NiFe2O4. Thus, this study offers an effective route for the synthesis of Pd/PdO-functionalized NiFe2O4 NPs to achieve n-butanol detection with excellent sensing performance.