Synthesis of ZnO Nanoparticles via Wet Chemistry

Zinc nitrate and sodium hydroxide were precursors in a wet chemical process to create zinc oxide nanoparticles (Zn NPs), with sodium borohydrate serving as a stabilizing agent. The procedure, adapted from Behera [19 ] with some modifications, began by dissolving approximately 2.79 g of zinc nitrate hexahydrate [Zn (NO₃)₂·6H₂O] in 100 mL of distilled deionized water through vigorous stirring for one hour. A solution of 0.48 g of sodium hydroxide (NaOH) in 60 mL of distilled deionized water was then prepared, and 1 mL of 1% NaBH₄ was added after the dissolution of zinc nitrate. Sodium hydroxide solution was slowly added dropwise to the mixture using a burette, stirring overnight for 12 h to achieve a reduced nanosize. The resulting precipitate was left to settle, then dried in an oven at 80 °C after being filtered under suction and repeatedly cleaned with distilled dH₂O. The obtained zinc hydroxide (Zn (OH)₂) was transformed into ZnO through calcination in a muffle at 500 °C, yielding the desired smaller-sized ZnO nanoparticles.