H2S gas sensing properties of bare and Pd-functionalized CuO nanorods

CuO one-dimensional nanostructures functionalized with Pd were synthesized using a three-step process: thermal oxidation of Cu foil in air, dipping in a PdCl2 solution, and thermal annealing. The gas sensors fabricated from the multiple net worked Pd-functionalized CuO nanorods showed substantially enhanced electrical responses to H2S at 300 °C. The multiple networked CuO nanorod sensors showed a response of 400% at 100 ppm H2S at 300 °C, whereas the Pd-functionalized CuO nanorod sensors showed a response of 31,243% under the same conditions. The recovery time of the Pd-functionalized nanorod sensor is 5–8 times shorter than that of the bare–CuO nanorod, whereas the response time of the former was 2–3 times longer than that of the latter. In addition, the H2S gas sensing mechanism was examined, and the origin of the enhancement of the H2S gas sensing properties of the CuO nanorods by functionalization with Pd is discussed.