Low temperature detection of nitric oxide by CuO nanoparticles synthesized by pulsed laser ablation

Abstract

Fast, selective and low-cost sensors for nitric oxide (NO) detection are highly desirable due to the harmful effects of this gas. Low temperature NO detection is challenging, requiring selective and effective catalytic processes. Here, we present an experimentally based CuO-NO interaction model in the 50–400 °C temperature range and a promising NO chemoresistive sensing device working at 50 °C based on CuO nanoparticles (NPs) produced by pulsed laser ablation in liquid environment (PLAL). Ligand-free Cu/Cu2O nanostructures produced by PLAL were converted into 35 ± 12 nm CuO NPs by 400 °C annealing, and analysed by X-Ray Diffraction, Scanning Electron Microscopy and Energy Dispersive X-ray techniques. The chemoresistive sensor is produced by drop-casting the CuO NPs suspension onto an interdigitated electrode and tested in a flow-controlled test chamber. Below 250 °C, oxidation behavior is recorded, while above 350 °C reduction takes place, with a peculiar transient regime observed at 300 °C. A full model of CuO-NO interaction is proposed, based on Langmuir adsorption theory and kinetics barriers extracted by response curves in the 50–400 °C temperature range. A peculiar catalytic activity of CuO NPs emerges in combination with oxygen species absorbed at different temperature, leading to effective NO detection. The ease and scalability of CuO NPs production by PLAL and the reported fast and selective NO sensor working at 50 °C open promising routes towards exploitation for massive and affordable harmful gas detection.