Tunable morphology, bandgap, photocatalysis and magnetic properties of Bi6Fe2Ti3O18 nanocrystals by doping cobalt ions

At present, the researchers pay much more attention on thin films and ceramics of Bi6Fe2Ti3O18 with different element doping, not nanomateials. Therefore in this work, the single-crystalline Bi6Fe2-xCoxTi3O18 (BFCTO) (x = 0–0.5) nanocrystals were synthesized successfully by the hydrothermal method. As the Co ions doping concentration increase, the main morphology of BFCTO nanocrystals changed from nanoplate to nanosheet. Meanwhile, doping Co ions in the BFTO can efficiently reduce the band gap of products. As the Co ions doping concentration increase to x = 0.5, the corresponding bandgap is shorten from 2.576 to 2.201eV. Besides, the BFCTO-0.5 sample exhibited optimal ultraviolet (UV)-light-driven photocatalytic activity for decomposition of rhodamine B (RhB). At room temperature, upon Co doping, the samples have spontaneous magnetic moments, indicating the ferromagnetic nature. The hysteresis loop of BFCTO-0.2 and BFCTO-0.1 nanocrystals obtained the maximum remnant magnetization 2Mr of 0.27emu/g and the maximum coercive field 2Hc of 1600Oe, respectively. The BFCTO-0.5 nanocrystal performed the best ferromagnetism with a saturated magnetization Ms of 2.15emu/g. All the results indicate the BFCTO nanocrystals have potential applications in data storage, sensors and nanodevices.