Visible light active Cu2+ doped TiO2 for simultaneous removal of Rhodamine-B and Cr (VI)

Cu-doped TiO2 with different weight percentages of Cu loading (1% to 4%) were synthesized by the sol–gel technique and characterized by powder XRD, SEM and TEM. 1 and 2 wt% Cu2+ doping, Cu -TiO2 has a major anatase phase with a minor rutile phase, and with increasing Cu loading to 3% and 4%, rutile phase increasing were observed. UV–Vis absorption spectroscopy confirmed that with Cu doping, the band gap of TiO2 decreased. PL and XPS was used to understand the optical properties and the surface elemental composition and the oxidation state of the elements of the prepared catalysts. Photocatalytic activity of synthesized materials was assessed for the visible light assisted removal of Rhodamine B and Cr (VI) individually and simultaneously. The mineralization of the pollutant was confirmed by the TOC analyzer. 3% Cu-doped TiO2 shows the highest degradation and mineralization when compared to other TiO2 materials. The radicals trapping experiments were conducted to determine the mechanism and it was found that O2–• and e- are the active radical species for the photocatalytic degradation of Rhodamine B and Cr (VI). The simultaneous removal of Rhodamine B and Cr (VI) was higher compared to the removal of individual pollutants.