Transition metal ions as a tool for controlling the photocatalytic activity of MWCNT-TiO2 nanocomposites

MWCNT decorated with undoped and Cu or Mn-doped TiO2 nanoparticles were synthesized successfully. PXRD patterns show the diffraction plans specific to MWCNT, anatase, and rutile phases of TiO2. The ratio between anatase and rutile phases differs from sample to sample. Through EPR spectroscopy, the defect and the valence states of the dopant ions in the TiO2 lattice were shown and correlated with XPS results. The morphology of the samples was analyzed by SEM and TEM. The photocatalytic activity of the samples was evaluated against RhB aqueous solution under UV irradiation. The sample containing Cu2+ ions has the best photocatalytic performance. The photocatalytic mechanism was explained based on the correlation of structural characteristics, optical properties, ROS species generation, and scavenger experiments. The electrochemical performance of the SPE electrode modified with MWNCT-TiO2:Cu towards RhB detection was tested, and the obtained sensitivity is higher than that corresponding to bare SPE.