Investigation of CdO nanostructures synthesized by microwave assisted irradiation technique for NO2 gas detection

Cadmium oxide nanostructures were prepared with simple and cost-effective chemical route assisted by microwave irradiation. The synthesized samples were characterized by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Selected Area Electron Diffraction (SAED), Energy Dispersive X-ray (EDX) analysis and Fourier Transform Infrared spectroscopy (FT-IR) techniques. Highly crystalline CdO nanostructures with different morphology (spherical and rod-like) have been obtained by the microwave-assisted procedure adopted without any post-synthesis annealing treatment. Furthermore, the formation of these CdO nanostructures can be easily addressed within short times (5-15 min) by a fine tuning of the microwave irradiation. The CdO nanostructures have been investigated as sensing layer in resistive sensors and tested for NO2 sensing at mild temperature. The sensors have shown high response to NO2 down to 0.5 ppm at low operating temperature of 100 °C and high selectivity against CO.