Visible-light (VL) photocatalysis has been regarded as an intriguing technology for the control of persistent environmental pollutants. In this study, the novel homogeneous Co doped-Bi/BiOBr nanocomposites (CB-X) were prepared via a facile one-step hydrothermal method, featured with a uniform 0D Bi nanodots distribution on 2D Co-doped BiOBr nanosheets, and the photocatalytic performance was evaluated by decomposing the BPA as a prototype contaminant. The degradation experiment indicated that the optimal CB-2 nanocomposite exhibited the best photocatalytic activity with a 94% removal efficiency of BPA under the VL irradiation of 30 min; And the corresponding apparent rate constant (k) was as high as 0.107 min-1, which was 10.7 times greater than that of Bi/BiOBr (0.010 min-1). Benefiting from the modulation effect of Co-doping on the intrinsic electron configuration of Bi/BiOBr, the elevated VL adsorption capacity and accelerated h+/e- pairs separation rate were achieved, which were evidenced by photoluminescence (PL) spectroscopy, photo-electrochemical measurements and density functional theory (DFT) calculation. Moreover, the major reactive species in CB-X/VL system were uncovered to be •O2- and 1O2, whereas •OH and h+ presented a secondary contribution in the BPA elimination. Finally, the possible photocatalytic mechanism involved in CB-X nanocomposites and BPA degradation pathways were proposed on the basis of the various intermediates and products detected by LC-MS/MS.
Keywords: Bi nanodots; Bismuth oxybromide nanosheet; Bisphenol A; Cobalt doping; Visible-light photocatalysis.
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