Photocatalytic Properties of Ti-Doped BiFeO3 Bulk and Nanoparticles for Solar Hydrogen Fuel Generation.

This investigation aims to synthesize an effective photocatalyst for solar hydrogen (H2) fuel production. The polycrystalline ceramic pellets of 10% Ti-doped BiFeO₃ (BFTO) were prepared by the conventional solid-state reaction technique. After grinding into micro-meter sized powders, this bulk sample was mixed with isopropanol and the solution was subsequently sonicated using an ultrasonic bath to obtain corresponding BFTO nanoparticles. The structural, morphological and optical properties of the prepared BFTO nanoparticles were then analogized with bulk BFTO sample, undoped bulk BiFeO₃ (BFO) sample and undoped BFO nanoparticles. A notable modification in the crystallographic structure of BFTO nanoparticles compared to other samples was observed. The X-ray diffraction patterns of BFTO showed a transition from rhombohedral perovskite structure to orthorhombic as Ti was doped. The impurity phases found in BFO sample decreased significantly in bulk BFTO which further became negligible in BFTO nanoparticles. The images from Field Emission Scanning Electron Microscope (FESEM) revealed the surface morphology of the BFTO pellets and demonstrated that the BFTO nanoparticles had a uniformly distributed, reduced grain size (range: 60-120 nm, average size: ~90 nm).The band gap energy of different samples calculated from their Diffused Reflectance Spectra (DRS) confirmed that like the undoped bulk BFO, the bulk and nanoparticles of Ti-doped BiFeO₃ can absorb solar radiation with wavelengths ranging from UV to visible region. The BFTO nanoparticles exhibited lower band gap energy compared to other samples which is indicative of its potential as a photocatalyst in solar energy application. The efficiency of the synthesized materials as photocatalysts will be checked to produce hydrogen via water splitting under visible light irradiation. [ABSTRACT FROM AUTHOR]