2.2. Green synthesis and chemical characterization of VNPs@Salvia officinalis
VNPs@Salvia officinalis was green synthesized according to a reported procedure [21]. Briefly, a 50 mL of the plant extract (5 mg /10 mL of deionized water) was added to 50 mL of sodium metavenadatein at the concentration of 0.02 M. Then, the reaction mixture was stirred at room temperature 100 minutes. After the time, a yellow-orange precipitate was formed. Deionized water was used to wash the residue for three times and centrifuged interval at 10000 RPM for 15 minutes. The vanadium nanoparticles were put under a hood to dry.