Novel synthesis of PbTiO3/CoFe2O4 based on graphene oxide as potential materials for enhancing efficient energy storage using multivariate optimization method

Hydrogen storage is key to developing fuel cells and hydrogen technologies for use in transportation, portable power, and stationary power. Hydrogen storage compounds are needed for renewable energy vehicles. With this aim, PbTiO₃/CoFe₂O₄ on graphene oxide (GO) was designed as materials of electrode for applications of electrochemical hydrogen storage through a straightforward approach. The hydrogen storage performance of the samples was characterized based on the chronopotentiometry technique in an alkaline environment. First, the experimental design was carried out using the rotating central composite method for three practical factors. After synthesizing the nanocomposite using the new process, charging and discharging were carried out using the chronopotentiometry method for 17 designed experiments, and then optimization was done using the response surface method. The discharge capacity of the PbTiO₃/CoFe₂O₄/GO nanocomposite was evaluated to be 2859.5 mAhg^-1 after 12 cycles. Cyclic voltammetry was then used to determine the pristine electrochemical properties of the PbTiO₃/CoFe₂O₄/GO nanocomposite, where the anodic and cathodic peak currents were about 0.0116 and -0.006 A, respectively. The products were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, elemental mapping and N₂ adsorption-desorption techniques. The results indicate the average crystallite size of 25.3 nm and average pore diameter of 2.17 nm in the case of PbTiO₃/CoFe₂O₄/GO nanocomposite based on the scherrer equation and BJH pore size distribution plot, respectively. Furthermore, electrochemical impedance spectroscopy (EIS) results showed that the polarization resistance of the PbTiO₃/CoFe₂O₄/GO sample is 176 Ω.