green nickel oxide is used in the manufacture of SOFC (Solid Oxide Fuel Cell) for electricity production. It has very high chemical purity and a fine particle size distribution that makes it an excellent choice for the manufacturing of SOFCs.
Green synthesis of NiO nanoparticles
The synthesized NPs were characterized using various techniques including XRD, FESEM and UV-Vis analysis. The NPs synthesized with aloe vera leaf extract, dragon fruit peel extract and papaya peel extract showed well-defined nanostructures that displayed few intercalations. However, the NiOx particles synthesized without extract exhibited a much higher crystallite size than those of the other three plants.
Biochemical Analysis of NPs
The antioxidant activity of the NPs was investigated using a number of biochemical assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azinobis-3-ethylbenzothiazoline-6-sulphonate (ABTS.+), ferric reducing antioxidant power (FRAP), hydrogen peroxide (H2O2), reducing power assay and superoxide dismutase (SOD) assays. The synthesized NPs exhibited good levels of antioxidant activity, indicating that the scavenging properties of the NPs are attributed to the bioactive compounds in the plant extracts.
Electrocatalytic performance of the NPs was also evaluated. Cyclic voltammetry measurements showed that the NPs possessed a significantly higher electrocatalytic surface area when compared to their dragon fruit and papaya counterparts. The NPs also exhibited a lower overpotential requiring only 433 mV for an overpotential of 10 mAcm-2, which is significantly lower than those derived from the other two fruits.
Besides demonstrating an improved electrocatalytic performance, the NPs also displayed strong bactericidal activity. The bacterial cells that were treated with the NPs and Mo doped NPs exhibited red fluorescence after exposure to DAPI, indicating that they were killed by the NPs.