Construction Of AgBr-based Composites And Study On Their Photocatalytic Activities

The liquid-phase synthesis methods were used to prepare three kinds of AgBr-based composite photocatalysts(AgBr/Mt,AgBr/g-C3N4 and AgBr/Bi OBr/Bi),which were characterized by XRD,SEM,XPS,UV-vis DRS,and FT-IR.The organic dyes and antibiotics were chosen as target pollutants to evaluate the photocatalytic activities of the obtained catalysts and the photocatalytic mechanisms were also proposed.Novel AgBr/Mt composite was synthesized by one-step precipitation method.Combination of adsorption and visible light-driven photocatalysis,the removal efficiency of Rhodamine B(Rh B)and methyl orange(MO)by AgBr/Mt reached 100% and 88%,respectively,and the catalytic performance of AgBr/Mt was better than Mt and AgBr.The enhancement of activity for AgBr/Mt was attributed to the effective separation of electron-hole pairs.The radical capture experiments showed that O2–· was the main active species and h+ also played an indispensable role for dyes degradation.A hydrothermal method was used to synthesize highly efficient AgBr/g-C3N4 photocatalyst,which exhibited a better photocatalytic activity for Rh B and MO degradation than pure g-C3N4 or AgBr.Photoelectrochemical test and Photoluminescence technique confirmed that the enhancement of activity was due to the fact that AgBr and g-C3N4 constructed a direct Z-scheme photocatalytic system.Free radical capture experiments and ESR technique confirmed that O2–· was the main active species for dyes degradation.The cycling test indicated that the reusability of AgBr/g-C3N4 was good.Bi OBr/Bi microsphere was solvothermally synthesized,and then AgBr/Bi OBr/Bi microspheres were obtained by an ion exchange method.Under visible light,the Rh B degradation rate by AgBr/Bi OBr/Bi was 1.4 and 4.9 times faster than Bi OBr/Bi and AgBr/Bi OBr,respectively.The enhancement of activity for AgBr/Bi OBr/Bi was due to the type II heterojunction between AgBr and Bi OBr,and the SPR effect of metal Bi.Free radical capture test confirmed that O2–· was the dominat active species.After three cycling rus,AgBr/Bi OBr/Bi still maintained a high activity,indicating that it was stable.Figure 50;Table 7;Reference 126...