NiO nanostructured powders were synthesized by an ultrasonic spray pyrolysis (USP) technique. The powders were characterized using low temperature adsorption (BET), X-ray diffraction, scanning electron microscopy (SEM), and a transmission electron microscopy (TEM). The final product of the ultrasonic spray pyrolysis is hollow microspheres with 5-7 μm in diameter. The microspheres are built from nanoparticles with 40-60 nm in diameter.
Yudin, A., Shatrova, N., Khaydarov, B., Kuznetsov, D., Dzidziguri, E., & Issi, J.-P. (2016). Synthesis of hollow nanostructured nickel oxide microspheres by ultrasonic spray atomization. Journal of Aerosol Science, 98, 30-40. https://doi.org/10.1016/j.jaerosci.2016.05.003 (Original work published 2016)