Eco‐Friendly Synthesis of Co ₃ O ₄ Nanoparticles Using <i>Ipomoea staphylina</i> Leaf Extract: Photocatalytic, Antibacterial, and Antioxidant Properties

Abstract Cobalt oxide (Co 3 O 4 ) and Mn‐doped Co 3 O 4 nanoparticles (NPs) were synthesized in a green, low‐price, and eco‐friendly manner via Ipomoea staphylina leaf extract. Characterization of the NPs was performed by XRD, FT‐IR, UV‐DRS, FE‐SEM, EDX, XPS, and PL. XRD analysis was used to calculate the average crystallite size of Co 3 O 4 NPS (28.37 nm) and Mn‐doped Co 3 O 4 NPs (24.98 nm) with a face‐centered cubic system. As confirmed by FE‐SEM, there is an agglomerated structure of the NPs. Mn doping caused the optical band gaps of the prepared NPs to decrease and move from E g = 3.12 to 2.90 eV. Congo red and Acridine orange dyes undergo photocatalytic degradation when exposed to a mercury lamp (250 W, 365 nm) at room temperature. After 60 min of irradiation, 20 mg of Mn‐Co 3 O 4 NPs were used to achieve degradation of Congo red and Acridine orange, which is 94.45% and 66.24%, respectively. The Mn‐Co 3 O 4 NPs that were synthesized have excellent antibacterial properties against Bacillus subtilis bacteria (22 mm) among the tested bacteria. The Mn‐Co 3 O 4 NPs were able to effectively inhibit 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) free radicals at 66.14%. These novel NPs extracted from Ipomoea staphylina can be effectively utilized for various environmental and medical applications.