Structural features of PN and its composites with metal oxides were analyzed using X-ray diffraction (XRD), as shown in Figure . The XRD pattern of PN synthesized by cyclic voltammetry and chronoamperometry (Figure with the spinel cubic phase due to the presence of hexagonal ZnO and Fe2O3, forming the bimetallic ZnFe2O4 . The absence of extra peaks confirmed the absence of impurities during the synthesis of metal oxides and PN composites. The average crystallite size (D) was calculated using Scherer's formula (eq. 6) :