Synthesis and characterization of kaolinite nanocomposite decorated with BiFeO3 nanoparticles for enhanced photocatalytic and electrochemical properties

Kaolinite-BiFeO3 photocatalyst was prepared by decoration of ferromagnetic BiFeO3 nanoparticles onto kaolinite surface. Comparative characteristics of kaolinite, bare BiFeO3 and kaolinite-BiFeO3 photocatalyst were examined by XRD, TEM, SEM-EDX, XPS, FTIR, VSM, UV-DRS, PL, zeta potential and BET techniques. The photocatalytic activities of the samples were evaluated by photodegradation of rhodamine B as a model reaction under different irradiations like UVA, visible and sunlight. The kaolinite-BiFeO3 exhibited more superior photocatalytic activity as compared with other samples, which is best fitted to pseudo- first-order kinetic. The reactive species trapping experiments indicated that photogenerated-holes play major roles in the degradation process whereas superoxide radicals possess a secondary effect. Furthermore, a novel electrocatalytic platform was designed by gold nanoparticles loaded on kaolinite-BiFeO3 modified carbon paste electrode surface and electrocatalytic activity of this platform was investigated for oxygen reduction reaction in alkaline medium. Electrochemical characterizations of bare surfaces and the Au/BiFeO3/kaolinite modified carbon paste electrode comparatively carried out with the electrochemical impedance spectroscopy, cyclic voltammetry, and chronoamperometry techniques. In addition, a novel amperometric H2O2 biosensor based on BiFeO3 nanoparticles as platform and Cress peroxidase as bio-component was prepared.