Non-photocatalytic electricity generation and thermoluminescence in natural hematite: application in hydroelectric cell and dosimeter

For the first time, environmentally friendly hydroelectric power cells (HEC) and thermoluminescence dosimeters (TL) were manufactured using natural hematite (-Fe₂O₃). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) studies confirmed the multimodal particle size range of 30-90 nm for natural -Fe₂O₃. Brunauer-Emmett-Teller (BET) analysis confirmed the mesoporous and nanoporous structure with an average pore size of 30 nm. X-ray Photoelectron Spectroscopy (XPS), photoluminescence (PL), ultraviolet-visible (UV-vis) spectral analyses confirmed the presence of oxygen vacancies on the surface of 1-Fe₂O₃. The surface area of natural hematite was considerable (33.48 m²/g), the band gap was small (1.7 eV), and the porosity was high (31%). A square -Fe₂O₃ hydroelectric power cell with an area of 4.84 cm² generated electricity by redox reaction and produced an open circuit voltage of 0.98 V, a stable short circuit current of 7.0 mA, and an open circuit power of 6.86 mW. The TL annealing curve is recorded using a hematite sample annealed at different temperatures (100 °C to 700 °C) and irradiated with a ⁶⁰Co gamma source with different radiation doses (100Gy,15kGy). Deconvolution based analysis of the TL glow curve reveals a prominent single emission band at 178 °C and high linearity in the dose range from 2kGy to 9kGy for the sample annealed at 400 °C. Oxygen vacancies, which function as luminous traps, are thought to be the cause of the observed behaviour. Chen's peak method and initial rise method are used to calculate trapping factors such as activation energy, frequency factor, and order of kinetics associated with the peak at 400 °C. Natural hematite has been discovered to be an excellent contender for green energy storage and dosimetric applications. (author)