Synthesis and Analysis of Electrospun SrTiO3 Nanofibers with NiO Nanoparticles Shells as Photocatalysts for Water Splitting

The coaxial electrospinning process was used to produce core/shell strontium titanate/nickel oxide (SrTiO3-NiO) nanofibers. First, poly (vinyl pyrrolidone) (PVP) was dissolved in deionized (DI) water, and then titanium (IV) isopropoxide [C12H28O4Ti] and strontium nitrate [Sr(NO3)(2)] were added into the solution to form the inner (core) layer. Polyacrylonitrile (PAN) polymer was dissolved in dimethylformamide (DMF) at a weight ratio of 10:90. Nickel oxide was mixed with the solution to form the outer (shell) layer. This coaxial electrospinning method generated uniform-size, defect-free fibers. The electrospun nanofiber samples were annealed at 600 degrees C for two hours in air in order to remove the organic part and crystallize the amorphous SrTiO3-NiO nanofibers. Water contact angles were determined to identify surface hydrophobicity of the nanofiber films. Ultraviolet (UV) spectrophotometry, Fourier transform infrared radiation (FTIR), and differential scanning calorimeter (DSC) techniques were used to characterize the structural properties of the SrTiO3-NiO nanocomposite fibers. The morphology and dimensions of the nanofibers were observed by scanning electron microscopy (SEM). The images showed fluctuation in the fiber diameters because of the two different polymeric solutions electrospun at the same time. The structures of the calcined nanofibers were determined by Raman spectroscopy and X-ray diffraction (XRD), which clearly indicated the formations of SrTiO3 and NiO nanofiber structures. The fabrication of such core/shell SrTiO3-NiO nanofibers through coaxial electrospinning suggests the further enhancement and development of photocatalytic behaviors of the new nanomaterials. This study can provide useful information for scientists, engineers, and manufacturers working in renewable energy and related fields, such as water splitting, sensors, solar cells, and catalysts.