Synthesis of porous CuO nanowires and its application to hydrogen detection

Porous nanowire-structured cupric oxide (CuO) film is synthesized by deposition of Cu on porous single-walled carbon nanotube (SWNT) substrate followed by a thermal oxidation process. Oxidation is done in air at a temperature range of 300–800 °C to oxidize the Cu while removing the SWNT template. The oxidation temperature determines the stoichiometry of the CuO formed, and thus the electrical property. The structures and electrical properties of the synthesized materials are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), and current–voltage measurements. Sensing property is examined using hydrogen gas. Gas sensing mechanism and the advantages of nanowire structure as a sensor are also discussed. The best response and recovery results are observed with the CuO nanowires oxidized at 400 °C at a working temperature of 250 °C.