Magnetic and electrochemical application of Ru doped Co3O4 thin films

This work describes the preparation of cobalt oxide and Ruthenium doped (x = 0.025, 0.05, 0.075, 0.1) Co3O4 thin films on glass and fluorine-doped tin oxide substrates by spray pyrolysis method. The synthesized samples were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDAX), Fourier Transform Infrared (FTIR), Raman Spectroscopy, X-ray Photoelectron Spectros-copy (XPS), UV-Visible spectroscopy, vibrating sample magnetometer (VSM), Cyclic voltammetry (CV), Linear Sweep Voltammetry (LSV) and Electrochemical Impedance analysis (EIS) to analyze phase purity, surface morphological features, elemental composition, molecular vibrations, optical absorption, magnetic behaviour, super capacitive behaviour and electrical characteristics respectively. The XRD pattern of Ru-doped Co3O4 showed no additional peak compared to Co3O4, with a peak shift observed that confirms the spinel cubic structure of Co3O4. The crystalline size of pure and Ru-doped Co3O4 (0.050) is about 22 nm and 38 nm, respectively. SEM images show pure Co3O4 has smooth and porous morphology, while Ru-doped Co3O4 showed porous, void and cluster formation and increased surface area. The EDAX spectra indicate that the synthesized films are non-contaminated. In Raman spectra, similar to 480,similar to 521, similar to 617, and similar to 689 cm(-1) are observed, corre-sponding to the Eg, F(2)g, F(2)g and A(1)g modes, respectively. From the XPS, binding energy observed at 281.6 eV and 283.6 eV attributed to Ru(3)d(5/2) and Ru(3)d(3/2), respectively. The band gap is about 1.49, 1.28, 1.34, and 1.44 eV for pure Ru-doped Co3O4 thin films. At Ru content x = 0.050, the film exhibits a superparamagnetic nature. The real capacitance of Ru-doped Co3O4 thin film is 158.1 F/cm(2) which is slightly increased than Co3O4 thin film. EIS measurement showed a semicircle attributed to oxygen evolution reaction and agrees well with experimental data.