2.2. Synthesis of nickel ferrite on silica substrate NiFe2O4@SiO2
This step was in accordance with the method of synthesis of nickel ferrite nanocomposites in silica media reported in other articles [18]. First dissolving 6.2 gr of nickel nitrate and 17 gr of iron nitrate each in 10 ml of deionized water and refluxing them and stir well with a magnetic stirrer for 30 minutes until complete mixing. Next, pour 60 ml of tetraethyl ortho-silica (TEOS) in 50 ml of ethanol and 10 ml of water and decrease the pH using acidic hydrochloric acid and then pour it dropwise into a decanter and solution. Allow the solution to be stirred for 2 hours until the solution is fully mixed. In the third step, pour the contents of the balloon into the crystallizer and place it partially in exposer of the air for 7 days and alcogel synthesized. After 7 days, the synthesized alcogel was incubated in the oven at 110 °C for 24 hours until dry and zerogel synthesized. Zerogel was then calcined for 2 hours in an 800 °C oven at a ramping rate of 10 °C /min in ambient atmosphere medium. Finally, the product was milled by a satellite mill and was named Powder (F-S) (Fig 1).
Fig 1: Schematic of Synthesis of nickel ferrite on silica substrate NiFe2O4@SiO2