Synthesis and catalytic activity of electrospun NiO/NiCo₂O₄ nanotubes for CO and acetaldehyde oxidation

NiO/NiCo₂O₄ nanotubes with a diameter of approximately 100 nm are synthesized using Ni and Co precursors via electro-spinning and subsequent calcination processes. The tubular structure is confirmed via transmission electron microscopy imaging, whereas the structures and elemental compositions of the nanotubes are determined using x-ray diffraction, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. N₂ adsorption isotherm data reveal that the surface of the nanotubes consists of micropores, thereby resulting in a significantly higher surface area (∼20 m² g^-1) than expected for a flat-surface structure (<15 m² g^-1). Herein, we present a study of the catalytic activity of our novel NiO/NiCo₂O₄ nanotubes for CO and acetaldehyde oxidation. The catalytic activity of NiO/NiCo₂O₄ is superior to Pt below 100 °C for CO oxidation. For acetaldehyde oxidation, the total oxidation activity of NiO/NiCo₂O₄ for acetaldehyde is comparable with that of Pt. Coexistence of many under-coordinated Co and Ni active sites in our structure is suggested be related to the high catalytic activity. It is suggested that our novel NiO/NiCo₂O₄ tubular structures with surface microporosity can be of interest for a variety of applications, including the catalytic oxidation of harmful gases.