Oxygen Adsorption and Desorption Kinetics in CuO Nanowire Bundle Networks: Implications for MOx-Based Gas Sensors

Copper oxide (CuO) nanostructures have demonstrated a good chemiresistive response for the sensing of various gases. The precise mechanisms this material and, in particular, kinetics to gases and sensor recovery remain much less investigated. For metal (MOx) gas sensors, oxygen adsorption desorption reactions on surface play major role kinetics, as most other react with order provide signal, nanoscale materials are known achieve faster response. Here we investigate CuO nanowire bundle (NWB) networks by analyzing electrical curves devices exposed oxygen. observation multiple time constants led us discuss potential related reaction diffusion species. By comparing rate extracted from obtained constants, conclude that defects into might be main reason observed large constants. Surprisingly, observe based as-deposited show 4–16 times compared after being annealed, depending temperature. result detailed characterization using scanning electron microscopy, X-ray diffraction, photoelectron spectroscopy, junctions between network hydroxylated explain result. Our investigation NWB provides direct understanding general will useful further understand optimize these