Surfactants-assisted preparation of TiO2–Mn oxide composites and their catalytic activities for degradation of organic pollutant

• Composites of manganese oxide on TiO2 were prepared in surfactant solutions containing Mn salt.
• Thickness of Mn oxide on TiO2 was controlled by changing the concentration of Mn salt, NH4OH and surfactants.
• Composites with thicker Mn oxide shell on anatase TiO2 showed the highest photocatalytic activity.

The composites of TiO2 and manganese oxide were synthesized in an aqueous surfactant/cosurfactant solution including Mn salt under basic condition. The morphology and the thickness of Mn oxide introduced on the surface of TiO2 could be controlled by changing the concentrations of Mn salt, NH4OH, surfactant, and cosurfactant. Also, the effect of heat treatment on the crystal structure of composite particles was investigated with the variation of calcination temperature. The composites were analyzed by using FE-SEM, TEM, XRD, and EDS. In addition, the catalytic performances of bare TiO2 and TiO2–Mn oxide for the degradation of methylene blue (MB) with the assistance of H2O2 at 25 °C were studied using UV–vis spectrophotometer. The composites with the crystal structures of anatase TiO2 and Mn3O4 having the thicker Mn oxide shell showed the highest catalytic activity for MB degradation among the synthesized catalysts.

TEM images of bare TiO2 particle (left) and TiO2–Mn oxide composite (right). Figure optionsDownload as PowerPoint slide