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Self-template synthesis of ATiO₃ (A = Ba, Pb and Sr) perovskites for photocatalytic removal of NO

Cai, Shiyi, Yu, Shan, Wan, Wenchao, Wen, Wen, Zhou, Ying
RSC advances 2017 v.7 no.44 pp. 27397-27404
X-ray diffraction, barium, barium titanate, hot water treatment, irradiation, lead, liquids, nanosheets, nitrates, nitric oxide, oxidation, photocatalysis, scanning electron microscopy, strontium, titanium dioxide, transmission electron microscopy
In this study, we report a self-template hydrothermal method for the synthesis of ATiO₃ (A = Ba, Pb, and Sr) perovskites using anatase TiO₂ nanosheets as precursors. Under hydrothermal conditions, ATiO₃ with different structures and morphology can be obtained. These samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The growth mechanism of ATiO₃ was explored by XRD evaluation over different reaction time, and it was observed that PbTiO₃ grows most slowly among all the samples including BaTiO₃, SrTiO₃, BaₓPb₁₋ₓTiO₃ and SrₓPb₁₋ₓTiO₃. The diffusion of A site sources to the solid surface and the reaction at solid/liquid interface could dominate the growth of ATiO₃. All the as-prepared samples exhibited activities toward photocatalytic oxidation of NO at ppb level. Specifically, PbTiO₃ has revealed the highest activity under both full spectrum and visible-light irradiation (λ > 420 nm), whereas BaTiO₃ exhibited best selectivity for the formation of ionic species (NO₃⁻), which could be ascribed to different electronic structures and charge separation efficiency of ATiO₃. This study provides some important hints to tune the photocatalytic performances (activity and selectivity) of ATiO₃ through the modification of A site elements.