Abstract:
NiO NPs have attracted the attention of scientific community due to multifunctional,
tunable nature, have wide band gap (3.7-4.0 eV), an intrinsic p-type semiconductor that
possess a wide range of applications. Green synthesis of NiO NPs, ZnNiO NCs and
AgNiO NCs are an efficient, fast, cheap, non-toxic, simple, and eco-friendly than
commonly used physicochemical methods. The present study focuses on green synthesis
by precipitation method, characterization, antimicrobial and antioxidant activities of NiO
NPs, ZnNiO NCs and AgNiO NCs synthesized using aqueous extract of Mangifera indica
fruit peals. The green synthesis of NiO NPs, ZnNiO NCs and AgNiO NCs were done by
using aqueous extract of Mangifera indica fruit peals, nickel nitrate, zinc nitrate and silver
nitrate solution at 60 ℃. Formation of NiO NPs, ZnNiO NCs and AgNiONCs were
confirmed by the appearance of cyan and dark gray color of the mixture and further
confirmed by spectral analysis. Parameters affecting the formation of NiO NPs, ZnNiO
NCs and AgNiO NCs were investigated and optimized. The respective optimum pH,
volume of extract, concentration of precursor, heating temperature; required for the
synthesis of NiO NPs, ZnNiO NCs and AgNiO NCs were 9, 30 mL, 0.1 M and 60 ℃
respectively. UV-Vis spectrum of synthesized NiO NPs, 3% ZnNiO NCs and 3% AgNiO
NCs shows peaks at 332 nm, 326 nm and 420 nm respectively. FT-IR spectral analysis
indicated the involvement of carbonyl (-C=O), hydroxyl (-O-H) and amine (-N-H)
functional groups in the formation and stabilization of NiO NPs, ZnNiO NCs and AgNiO
NCs. The XRD pattern showed the face centered cubic structures of synthesized NiO NPs,
ZnNiO NCs and AgNiO NCs with average crystal size of 20.0 nm, 17.0 nm and 25.4 nm
respectively. Doping of zinc on nickel oxide decrease the average crystal size and
increases band gap energy of the synthesized ZnNiO NCs. Doping of silver on nickel
oxide increases the average crystal size and decreases band gap energy of synthesized
AgNiO NCs. SEM image analysis showed the spherical, nano-rod and nano-flower shape
structures of the synthesized NiO NPs, ZnNiO NCs and
