Photo-Fenton Degradation of Ciprofloxacin Over Cu, Ce co-doped Monoclinic BiVO4 Photocatalyst

Abstract

We resort to aliovalent co-doping of BiVO4 to prepare Cu, Ce-doped BiVO4 photo-Fenton catalysts for ciprofloxacin degradation. Different compositions of co-doped BiVO4 were prepared by a hydrothermal synthesis protocol, and the sample with one mole percent Ce and two mole percent Cu (CE1CU2) exhibited optimum ciprofloxacin degradation photo-Fenton catalytic activity. Detailed structural characterization showed the formation of the monoclinic scheelite phase, along with the existence of Cu+/Cu2+ and Ce3+ in the co-doped BiVO4. The CE1CU2 sample demonstrated a lower charge recombination rate, thereby prolonging the electron lifetime and facilitating the reduction of H2O2 to •OH radicals. Moreover, the co-doped BiVO4 maintains high photocatalytic activity for ciprofloxacin degradation until the fifth reuse cycle. The active radical-trapping experiments confirm that •OH is the dominant reactive species, with contributions from e¯, h+, and O2•¯¯ active species. It appears that synergistic Ce3+/Ce4+ and Cu+/Cu2+ redox cycling facilitates continuous radical generation, regenerating the CE1CU2 catalyst and thereby enhancing its photo-Fenton performance and stability.