“…In Mondal et al.’s work, the synthesis of nanostructured hollow NiS submicrometer spheres was completed with an ultrasonic spray pyrolysis (USP) method, which had been previously reported . The solution, which was composed of NiCl 2 ⋅6H 2 O, Na 2 S 2 O 3 ⋅5H 2 O, and colloidal silica, was synthesized with a previously described procedure . Firstly, they loaded the solution to a USP ultrasonic cell, after whose system was removed with argon atmosphere for half an hour, and then, they nebulized the solution using an ultrasonic atomizer and made the aerosol mist with carried argon using a tube furnace at the temperature of 450 °C.…”