Formaldehyde vapour sensing property of electrospun NiO nanograins

Beads free polyvinyl alcohol (PVA)/NiO nanofibers with an average diameter of 400 nm were successfully prepared through the electrospinning method. NiO nanograins were formed along the axis of the nanofiber due to the calcination of as-spun fibers for 24 h at 450 °C and their presence was confirmed by FESEM. NiO nanograins were characterized by XRD, XPS and FTIR. The characterization results showed the presence of NiO in nanograins and its polycrystalline nature with ionic states. The sensing studies of NiO nanograins were performed towards the pulmonary disease breath markers and they showed better response towards formaldehyde vapour at 350 °C. Calcined NiO grains showed a good response towards the 11–1145 ppm of formaldehyde vapour at the operating temperature of 350 °C. NiO nanograins also showed quick response time (37 s) and recovery time (14 s) towards 46 ppm of formaldehyde. A sensing mechanism was proposed for the formaldehyde vapour interaction at 350 °C with NiO nanograins.