Keshav Y. Rajpure

Reliable detection of SO ₂ at low operating temperatures remains a significant challenge for metal oxide gas sensors, particularly in harsh refinery environments where selectivity and stability are critical. In this study, ZnFe ₂ O ₄ thin films with compact and porous morphologies are deposited via spray pyrolysis to investigate their suitability for SO ₂ sensing in refinery environments. The rigorous structural analysis reveals a strong correlation between crystalline features and sensing performance. In particular, an increased degree of spinel inversion enhances the sensor response by facilitating charge transport and surface reactivity. The porous films exhibit superior sensing behavior compared to compact films, owing to their higher surface area and increased availability of active adsorption sites. The optimized ZP375 sensor demonstrates a linear response towards SO ₂ concentration up to 200 ppm, with a low detection limit of 0.41 ppm. The sensor exhibits optimal performance at an operating temperature of 150°C and demonstrates excellent selectivity towards SO ₂ in the presence of other common interfering gases typically encountered in refinery environments. The sensor further exhibits long‐term stability extended up to 30 days. The results highlight the potential of spray‐deposited ZnFe ₂ O ₄ thin films as robust and energy‐efficient sensing materials for SO ₂ monitoring in industrial emissions from petrochemical refineries.

We have analyzed the thermodynamics of slowly rotating magnetized Kerr black-hole following Newman–Janis prescription with typical spin parameter [ ] (nearly static) in the background of nonlinear electrodynamics. The nonlinear electrodynamics is parameterized with two parameters [ ] and [ ]. We consider two values of the [ ], namely [ ] and [ ]. In particular, we have studied the Bekenstein–Hawking entropy, Hawking temperature, angular momentum, specific heats at constant angular momentum. The specific heat profiles show that the black-hole becomes unstable for all the values of event horizon radius.

Titanium dioxide (TiO₂) and doped TiO₂ have emerged as efficient photocatalytic materials for the degradation of harmful dyes released in water. The doping significantly increases the photocatalytic activity of TiO₂ by enhancing light absorption in visible region and by alteration of structure, surface area and morphology etc. The doping of TiO₂ has been achieved with various elements from the transition metal series, ions, nitrogen, with rare earths and other metallic nanostructures. Recently, significant new developments were noticed in the literature about doping of TiO₂ with new materials using different strategies. In this review, the basic information of TiO₂ as a photocatalyst is presented and the importance of doping to improve the photocatalytic performance of TiO₂ is highlighted. Recent reports about the doped TiO₂ from the literature are listed in tabular format and critically analyzed. The collective information presented will help to design new doping strategies and to come up with novel and more efficient TiO₂ based photocatalysts to develop a water purification technology.