Facile synthesis of nanostructured CuO for low temperature NO2 sensing

•Single step synthesis of nanosized crystallites CuO.•Sensing low concentration of toxic NO2 gas at only 50 °C without any interference from oxygen.•Temperature dependence sensing offered low activation energy of 0.18 eV.•Adsorption kinetics is detailed based on the Elovich model.

Detection of environmental pollutant and health hazardous, nitrogen dioxide (NO2) is reported using nanostructured CuO particulates (NPs). Powder X-ray diffraction and field emission scanning electron microscopy were used to probe crystalline phase and morphological details, respectively. Small crystallites of ∼10–12 nm and a strain of 4% were found in the leafy structure of CuO. Raman studies further supported the presence of nanosized CuO phase. This is the first instance of utilizing CuO NPs to detect 5 ppm of NO2 even at a low operating temperature of 50 °C. The highest sensitivity for NO2 was observed at 150 °C, for the first time, in CuO NPs. A low activation energy of 0.18 eV was found for sensing process. The CuO NPs sensor responded to NO2 within a few seconds and recovered totally under a minute. The kinetics of the NO2 gas adsorption on the CuO film surface was described following the Elovich model.

Graphical abstractNanostructured p-type CuO exhibited a quick sensing reaction (TR) as well recovery (TREC) of NO2 toxic gas at low temperature of 50 °C.Figure optionsDownload full-size imageDownload as PowerPoint slide