Synthesis and Characterization of NiFe2O4/g- C3N4/ZnO Heterogeneous Photocatalytic Nanocomposites and Their Applications For Dye Degradation and Water Splitting

Abstract

In this study, nanomaterials of NiFe2O4 and ZnO were synthesized by hydrothermal methods and g-C3N4 was synthesized by calcination in furnace. Subsequently, ternary composite of these components were prepared by solid state mixing in different ratios like 1:1:1, 1:3:1, and 3:1:1 w/w of NiFe2O4, g-C3N4 and ZnO as synthesized materials respectively. The synthesized nanocomposites were characterized by SEM and XRD while DRS was also carried out to find out their energy band gaps. The SEM depicted the morphology of the sample with perfect crystallite size. NiFe2O4 had a perfect rectangular plates like structure while g-C3N4 was a layered material because of the presence of graphene. ZnO was agglomerated in a beautiful flower shaped pattern and the nano composite of all the three materials appeared in the form of a sandwich with the layering of g-C3N4 and ZnO on the rectangular NiFe2O4 plates. The XRD revealed the tetragonal planes for NiFe2O4 and the hexagonal planes for ZnO while the g-C3N4 showed the diffraction planes with no extra peaks present in the sample which indicated the purity of the sample. Degradation studies of the dye methyl orange were carried out by UV-VIS spectrophotometer with highest degradation efficiency of 78% by composite 1:1:1 which showed the best activity. The degradation efficiency of 1:3:1 and 3:1:1 was 33% and 19% respectively. Water splitting was carried out by CV technique in the presence of KOH where the conductivity increased by increasing scan rate and current which indicated the stability and uniformity of the nano composite.