2D/2D step-scheme α-Fe2O3/Bi2WO6 photocatalyst with efficient charge transfer for enhanced photo-Fenton catalytic activity

Although the traditional Fenton reaction is considered an effective strategy for solving problems caused by environmental pollution, construction of an efficient photocatalytic system by coordinating the Fenton reaction is challenging. In this study, 2D/2D step-scheme α-Fe2O3/Bi2WO6 (FO/BWO) heterostructure photo-Fenton catalysts were successfully fabricated by a facile hydrothermal method. The as-prepared materials were characterized by XRD, FT-IR, TEM, XPS, UV-vis DRS, PL, I-t, EIS, and BET analyses. Under visible light irradiation, FO/BWO exhibited remarkably high and stable photo-Fenton catalytic activity for the degradation of methyl blue (MB) at low concentrations of H2O2. It was noted that FO/BWO (0.5) displayed a significantly enhanced photo-Fenton catalytic activity, which was 11.06 and 3.29 times those of FO nanosheets and BWO nanosheets, respectively. The notably improved photo-Fenton catalytic activity of FO/BWO was mainly due to the combination of H2O2 and FO under light illumination and the presence of the 2D/2D S-scheme heterostructure, with the large contact surface, abundant active sites, and efficient separation rate of photogenerated carriers playing contributory roles. Additionally, a possible catalytic mechanism for the FO/BWO composite was preliminarily proposed via active species trapping experiments. In summary, this study provided new insights into the synthesis of an effectively heterogeneous 2D/2D S-scheme photo-Fenton catalyst for degradation of organic pollutants in wastewater.