Exploring the structural and electrochemical sensing of wide bandgap calcium phosphate/CuxFe3-xO4 core-shell nanoceramics for H2O2 detection

Calcium phosphate/ CuxFe3-xO4 core-shell nanoceramics have been synthesized using the organic sol-gel process and calcined at 600 oC. The nanoceramics were explored by X-ray powder diffractometry (XRD), transmission electron microscopy (TEM)), Fourier transform infrared spectroscopy (FT-IR), UV-visible Diffuse Reflectance spectra (DRS), and electrochemical techniques including cyclic voltammetry (CV), and electrochemical imped-ance spectroscopy (EIS). The FTIR results confirmed the presence of calcium phosphate (CP) and CP coated with Cu-ferrite (0-30 mol% Cu:Fe3O4) core-shell nanoceramics. TEM analysis displayed nanospheres of calcium phosphate shielded with a porous spheres-like morphology with internal nanoparticles of about 33 nm. The reflectance spectra increase for all samples with increasing wavelength. Both direct and indirect gap transitions were detected with lower values of the direct case than the indirect type. The dielectric constant, refractive index, and optical electronegativity of all samples were calculated. When the ferricyanide was applied as the standard redox probe for the electrochemical characterization, CV and EIS results revealed a remarkable enhancement in the generated electrochemical signals. Moreover, modified screen-printed electrodes with the 20 Cu-CPF produced the highest redox current (0.198 mA) towards the direct oxidation of hydrogen peroxide. The obtained interesting features nominate the newly developed core-shell calcium phosphate/CuxFe3-xO4 nano -ceramics as promising candidates for talented magneto-optical and peroxide sensor applications.