Nanostructured SrTiO3 with different morphologies achieved by mineral acid-assisted hydrothermal method with enhanced optical, electrochemical, and photocatalytic performances

Abstract

SrTiO3 particles with different morphologies can be produced by hydrothermal reaction route using P25 TiO2, Sr(OH)2·8H2O, NaOH, and mineral acid as the starting materials in the presence of dilute nitric acid solution and heated at 220 °C for 24 h. The dilute nitric acid was replaced by the dilute hydrochloric acid or dilute sulphuric acid, and the reaction time was fine adjusted, and this eventually lead to the formation of nanoparticles or mixing of cubes and nanoparticles. Pure SrTiO3 can be obtained by changing the mineral acid to nitric acid or hydrochloric acid and adjusting the reaction time from 24 to 40 h. The mineral acid in the synthetic parameter was changed to sulfuric acid, and the synthesized SrTIO3 sample contained SrSO4 impurities. The electrochemical investigations confirmed that the performance of SrTiO3 rhombus particles in terms of rate capability was significantly higher as compared to the SrTiO3 nanoparticles or mixing of cubes and nanoparticles. Photocatalytic activity test indicated that the SrTiO3 rhombus particles exhibited an exceptional photocatalytic activity for the removal of congo red dye under simulated sunlight irradiation than that of other SrTiO3 samples. The variation tendency of photocatalytic activity for different SrTiO3 samples can be ascribed to the synergistic effects of impurity concentration, energy band, adsorbed oxygen concentration, optical absorption coefficient, charge carrier utilization and separation efficiency, and crystal surface exposure.