Nanostructural evolution of hydrothermally grown SrTiO₃perovskite and its implementation in gaseous phase detection...

A group of SrTiO₃nanostructures with unique nano-architecture have been synthesized in the current study. Sol-gel derived TiO₂nanoparticles along with Sr(OH)₂solution was processed with facial hydrothermal reaction at 180 °C and highly stable and distinct morphologies of SrTiO₃were developed after different reaction time. Nanobush, nanograss, nanorod and nanosphere morphologies were created after 10, 14, 18 and 24 h of hydrothermal reaction. SrTiO₃nanosphere was transformed into nano-hollow sphere morphology after thermal annealing at 600 °C. Detailed morphological, structural and chemical characterizations were carried out for all the distinct nanoforms of SrTiO₃where they exhibited high crystallinity, and chemical stability along with excellent surface properties like high porosity, roughness, and large effective surface area. Due to having rich surface properties, all the SrTiO₃morphologies were then implemented for gaseous phase detection of multiple volatile organic compounds (VOCs). However, all the SrTiO₃nanoforms showed ethanol selective behavior among all the VOCs. Nanograss and nano-hollow spheres exhibited excellent ethanol sensing with 69 and 78 response values (R_v/R_a) in 50 ppm ethanol at 150 °C with appreciably fast response/recovery times of 36 s/34 s and 150 s/ 58 s, respectively. Additionally, all the SrTiO₃nanostructures exhibited anti-humidity characteristics and potential sensing in humid ambient (up to 80% RH). Later, the ethanol selective behavior of SrTiO₃was established by density functional theory simulations which envisaged the highest negative adsorption energy and smallest distance (r) for ethanol molecule, implying stable adsorption with SrTiO₃(110) system.