A new-type of semiconductor Na0.9Mg0.45Ti3.55O8: preparation, characterization and photocatalysis

A new-type of semiconductor photocatalyst Na0.9Mg0.45Ti3.55O8 (NMTO) was prepared by a simple hydrothermal method for the first time. NMTO single crystal nanosheets with dominant {0 0 1} facets were obtained at 300 degrees C with 1 M NaOH over 40 min. HRTEM and XPS analyses confirmed the well crystallized nanosheets. NMTO was demonstrated as a direct semiconductor with a band gap of about 3.55 eV. Pure NMTO exhibited high photodegradation ability for methylene blue (MB) under UV-visible light irradiation. The trapping experiments indicated that the photogenerated holes were mainly responsible for the MB photodegradation. The presence of H2O2 significantly improved the photocatalytic activity of NMTO by inhibiting the electron-hole recombination through capturing the photogenerated electrons. A possible mechanism for the photodegradation of MB over NMTO is proposed. This work highlights the potential application of NMTO in the field of energy conversion.