Facile synthesis of C–Ta4+ co-doped NaTaO3 and rGO nanocomposites with enhanced visible light photocatalytic performance

Nanocomposites of C–Ta 4+ co-doped NaTaO 3 and reduced graphene oxide (C-NTO/rGO) with highly efficient photocatalytic activity were fabricated by a one-step solvothermal reaction. The optimum composites C-NTO/3rGO (with 3 wt% rGO) exhibited superior photocatalytic activity for the degradation of RhB over a mono-component counterpart under visible light irradiation . The photocatalytic efficiency was found to be as high as 97% for 90 min. Both XRD and XPS characterizations indicated that the doping of carbon into the NaTaO 3 lattice leads to the reduction of Ta 5+ to Ta 4+ . Furthermore, the co-doping significantly narrows the band gap (about 2.8 eV). Photo-luminescence (PL), time resolved transient PL decay spectra and photo-current results confirmed that photo-induced hole-electron pairs can be effectively separated resulting from the introduction of rGO. The synergistic effect of a decreased band gap and highly effective separation of photo-generated electrons and holes may be responsible for the enhanced photocatalytic activity of the fabricated nanocomposites. Both h + and •OH active radicals were found to be the key factors for the photo-decomposition process of RhB over the nanocomposites, while •O 2 − was also involved to a smaller extent. A possible photo-degradation mechanism for C-NTO/rGO was proposed on the basis of the experiments results.