The Synthesis And Characterization Of CaTiO₃ Nanostructures With Ultraviolet Light Photocatalytic Activity

As a typical representative of the perovskite oxide, calcium titanium (CaTiO3) is of both fundamental interest and practical importance in many disciplines such as optical science, electronic engineering and biocompatibility. CaTiO3 nanostructures can be used as a potential efficient photocatalyst because easy synthesis, low-cost, and high chemical stability in acid water environment. CaTiO3 nanostructures with different morphology and size will bring out different photocatalytic property. This paper utilized the hydrothermal method to prepare CaTiO3 nanostructures by changing the mineralization concentration, time, temperature and additives. Furthermore, the growth mechanism of the nanostructures and the photocatalytic degradation performance of Rhodamine B under UV irradiation were investigated. Glucose-assisted hydrothermal method was also extended to the preparation of PbTiO3 and SrTiO3 nanostructures. Main results are summarized as following:(1) The morphology of hydrothermally synthesized CaTiO3 nanostructures developed from hollow tube (length 1μm, width 500nm, height 500nm) to irregular thick sheet (length 600nm～1μm, thickness 200nm～500nm) with the KOH concentration changing from 0.25M to 8M. Correspondingly, the photocatalytic efficiency parameter K value increased from 0.0223 to 0.0368, and finally reduced to 0.0101. When KOH concentration remained 0.5M, the hydrothermally synthesized CaTiO3 nanostructures was still hollow tube (length 1μm, width 500nm, height 500nm), but the surfaces of the nanostructures became more smooth. The photocatalytic efficiency parameter K value increased from 0.0109 to 0.0370, and finally reduced to 0.0210. The improvement of photocatalytic efficiency was probably due to the larger surface area, which strengthened the redox ability of photoinduced electron-hole pair.(2) The morphology of hydrothermally synthesized CaTiO3 nanostructures evoluted from hollow tube (length 1μm, width 500nm, height 500nm) to the football-shaped body (the long axis 500nm, the short axis 300nm), and finally to the crosswise-like shape (length 1.3μm, width 1.3μm, height 500nm) with the sodium citrate concentration increased from 0M to 0.032M. Correspondingly, the photocatalytic efficiency parameter K value increased from 0.0109 to 0.0402, and finally reduced to 0.0055.(3) The morphology of hydrothermally synthesized CaTiO3 nanostructures changed from hollow tube (length 1μm, width 500nm, height 500nm) to the approximate sphere (diameter 100nm～600nm), and then to sphere (diameter 400nm～700nm), finally to the irregular morphology particles (50nm～80nm) with the glucose concentration increased from OM to 0.15M. The corresponding photocatalytic efficiency parameter K value increased from 0.0370 to 0.0436, and finally reduced to 0.0288. Glucose-assisted hydrothermal method has been applied to the preparation of PbTiO3 and SrTiO3 nanostructures. The morphology of hydrothermally synthesized PbTiO3 nanostructures changed from block (length 300nm, width 100nm, height 50nm) into the irregular morphology particles (80nm～120nm) with the glucose concentration increased from 0M to 0.3M. The morphology of hydrothermally synthesized SrTiO3 nanostructures changed from spherical shell (diameter 200nm) to the irregular morphology particles (100nm～150nm) with the glucose concentration increased from 0M to 0.3M. These results indicate that glucose-assisted hydrothermal method could be a universal method for the preparation of perovskite oxide nanocrystals.