Enhanced H2S gas sensing properties of p-type CuO nanorods functionalized with Pd

초록

CuO nanorods functionalized with Pd were prepared using a three-step process comprising thermal oxidation of a copper foil, sputter deposition of Pd, and annealing. The sensors were fabricated using the Pd-functionalized CuO nanorods. Scanning electron microscopy showed that nanorods with diameters ranging from a few tens to a few hundreds of nanometers and lengths of a few micrometers were coated with the Pd nanoparticles with a mean diameter of ~15 nm. Transmission electron microscopy and X-ray diffraction showed that the nanorods were monocrystalline monoclinic CuO. On the other hand, the nanoparticles were confirmed to be mainly amorphous but partly nanocrystalline face-centered cubic Pd. The multiple-networked CuO nanorod sensors showed a sensitivity of 2.43% at 100 ppm H2S at 300 oC whereas the Pd-functionalized CuO nanorod sensors showed a sensitivity of 15.74% under the same conditions. Pd-functionalization decreased the recovery time for the CuO nanorods considerably at every H2S concentration despite the response time being decreased or increased slightly depending on the H2S concentration. In addition, the enhancement of the sensing properties of the CuO nanorods by functionalization with Pd is discussed.