Structural, optical, morphological and electrochemical properties of dual-shaped SrTiO3 nanostructures with enhanced photocatalytic and supercapacitor performances

Abstract

The changes in the intermediate products during the photocatalytic degradation of pollutants are particularly important for understanding the degradation mechanism. Herein, we plan a synthesis and characterization of SrTiO₃ NPs by performing the hydrothermal method to create high-purity nanomaterials with controlled shapes at low temperature. The structural phase, functional group, optical, morphology, elemental composition and electrochemical properties of SrTiO₃ NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–Vis), photoluminescence spectroscopy (PL), Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS or EDAX), cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). Based on the XRD characterization, the SrTiO₃ NPs have a perovskite nanocrystalline structure with an average particle size of 49.2 nm. FT-IR analysis of the SrTiO₃ material showed the metal-oxygen bond (Ti–O) stretching vibrations at 613 cm⁻¹, respectively. UV–visible spectroscopy of the studied material indicated the λ_max peak at 315 nm, beside with the band gap (E_g) value of 3.18 eV. Electronic band structures of SrTiO₃ NPs have been carried out by performing DFT computations with the hybrid PBE efficient approach. SEM images show the NPs were of cubic perovskite structure with an average crystalline diameter ranging between 50 and 120 nm for the resultant product. The elemental composition mapping of the synthesized material containing Sr, Ti and O elements is confirmed by EDS analysis. The electrochemical process happening in the SrTiO₃ sample had been verified by the CV curves, which displayed redox maxima. The formed material's capacitive reactivity and usefulness as electrodes in energy-storing technologies have been shown by GCD scans. The degradation results revealed that SrTiO₃ NPs exhibited high photocatalytic activity, degrading 85 % of the Congo red dye as a solution in 120 min at 582 nm when subjected to sunlight. This combined computational and experimental study reveals that SrTiO₃ NPs show superior photocatalytic activity, making them vastly effective for environmental remediation and energy technologies, particularly in degrading organic pollutants in wastewater treatment and enabling enable energy conversion.