Fabrication of microsphere-like Bi3O4Cl/BiOI Z-scheme heterostructure composites and its enhanced photocatalytic performance for degradation of MO and RhB

Microsphere-like Bi3O4Cl/BiOI Z-scheme heterostructure photocatalysts with improved photocatalytic performance were synthesized by hydrothermal method. SEM images showed that Bi3O4Cl had morphological regulation effect on BiOI, which could greatly increase the active sites of the composites. And a possible process for the change of morphology was put forward. Two dyes with different charging properties (MO and RhB) were selected to evaluate the activities of the prepared photocatalysts. As a consequence, the 10%Bi3O4Cl/BiOI composite showed 99.8% of the degradation efficiency for MO degradation in 90 min of simulated sunlight irradiation, the degradation rate constant (0.0577 min(-1)) was 28.9 and 5.5 times higher than that of pure Bi3O4Cl and BiOI, respectively. Similarly, the 10%Bi3O4Cl/BiOI composite had more superior photocatalytic performance than pure Bi3O4Cl and BiOI. The enhancement of photocatalytic performance was mainly attributed to the increased light absorption, charge separation efficiency and specific surface area, which was proved by DRS, PL, EIS and N(2)adsorption-desorption characterizations. Further, the radical trapping experiments confirmed that holes (h(+)) and superoxide radicals (O-center dot(2)-) were the main active species for the photodegradation. Combining with the DRS and trapping experiments, a possible Z-scheme heterojunction photocatalytic mechanism was proposed.