TiO2/EDTA-rich carbon composites: Synthesis,characterization and visible-light-driven photocatalytic reduction of Cr(VI)

TiO₂/EDTA-rich carbon composites (TiO₂/EDTA-RC) have been successfully synthesized via a low temperature carbonization process. TiO₂/EDTA-RC exhibits marked absorption of visible light and excellent photoreduction of Cr(VI) activity under visible light irradiation (λ > 420 nm). Due to the high carboxyl group content and strong coordination ability of EDTA, TiO₂-EDTA complex can be easily fabricated between EDTA incorporated in carbon sheet and titanol group on the surface of TiO₂. TiO₂-EDTA complexes on the surface of TiO₂/EDTA-RC, the LMCT complex, are responsible for the prominent photoreduction of Cr(VI) properties of TiO₂/EDTA-RC under visible light irradiation. In addition, the unique structure of TiO₂/EDTA-RC is also propitious to the visible-light photocatalytic reduction of Cr(VI). Carbon sheet of TiO₂/EDTA-RC acts as a supporter. TiO₂ nanoparticles and EDTA homogeneously disperse into the carbon sheet supporter and form the TiO₂-EDTA complexes, which can avoid the aggregation of TiO₂ nanoparticles in the aqueous solution and provide more photocatalytic reaction points for the reduction of Cr(VI).