Enhanced visible-light driven photocatalytic degradation of bisphenol A by tuning electronic structure of Bi/BiOBr

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 O-center dot(2)- and O-1(2), whereas (OH)-O-center dot 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.

Automated summary

In this study, Co-doped Bi/BiOBr nanocomposites were prepared and their photocatalytic performance was evaluated. The nanocomposites exhibited excellent catalytic activity under visible-light irradiation, thanks to the modulation of their electron structure. The mechanism of BPA removal by the nanocomposites was also studied.