Impact of Ni and Fe on structual, photoluminescence and photocatalytic capacity of ZnO via Andrographis paniculata leaf extract

Biosynthesis of undoped ZnO, Ni (2 wt. %)-doped, Ni (2 wt.%) and Fe (2 wt. %) co-doped ZnO via andrographis paniculata leaf extract was demonstrated. Phase singularity as well as hexagonal phase was confirmed through XRD characterization, which was not disturbed by Ni-single and Ni-Fe-double doping. The reduction in crystallite size and lattice cell parameters, the change of peaks along the higher 2θ side, and the stable c/a ratio confirmed that Ni 2+ and Fe 2+ are correctly added in Zn-O sites, with no change in their crystal structure. The morphology of the particles and the presence of the elements were confirmed through SEM-EDS analysis. The enhanced light absorption and the tuning of the band gap (3.89 – 3.94 eV) by the inclusion of Ni/Fe showed a blueshift due to doping. The occurrence of Ni and Fe in the Zn-O lattice was recognized by FTIR examination, together with other functional groups. The origin of UV, violet, and blue emissions is ascertained to NBE, and a defect-related transition due to dopants is explored using an energy level diagram. The increased separation of charges; higher visible-range optical absorbance; enhanced surface area; as well as the existence of defect-based states lead to the better photocatalytic degradation efficiency that has been observed in Ni/Fe-doped ZnO. This improved photocatalytic behavior was tested with methylene blue and tetracycline. The Ni, Fe-doped ZnO exhibited a better degradation efficiency, and these materials will be useful for environmental remediation.