1 research outputs found
Synergistic Effect of Mo + Cu Codoping on the Photocatalytic Behavior of Metastable TiO<sub>2</sub> Solid Solutions
Codoping with Cu and Mo is shown
to have a synergistic effect on
the photocatalytic activity of TiO<sub>2</sub>. The enhancement in
activity is observed only if the synthesis route results in TiO<sub>2</sub> in which (Cu, Mo) codopants are forced into the TiO<sub>2</sub> lattice. Using X-ray photoelectron spectroscopy, Cu and Mo are shown
to be present in the +2 and +6 oxidation states, respectively. A systematic
study of the ternary system shows that TiO<sub>2</sub> containing
6 mol % CuO and 1.5 mol % MoO<sub>3</sub> is the most active ternary
composition. Ab initio calculations show that codoping of TiO<sub>2</sub> using (Mo, Cu) introduces levels above the valence band,
and below the conduction band, resulting in a significant reduction
in the band gap (∼0.8 eV). However, codoping also introduces
deep defect states, which can have a deleterious impact on photoactivity.
This helps rationalize the narrow compositional window over which
the enhancement in photocatalytic activity is observed