Assembly And Photocatalytic Properties Of Ultrathin Nanoplate PbBiO₂Br Based Composites

PbBiO2Br and g-C3N4 were prepared by a solvothermal process and a calcining process, respectively. PANI was successfully coated on the surface of PbBiO2Br by in-situ oxidation polymerization to yield PANI/PbBiO2Br composites.PbBiO2Br/g-C3N4 and PbBiO2Br/UiO-66-NH2 composites were prepared by solvothermal method. A series of characterizations were carried out on the materials,and their photocatalytic performance under visible light and synergistic mechanism were studied. Several conclusions are drawn as following:(1) PANI/PbBiO2Br composites were successfully synthesized by in-situ oxidation polymerization,and in the photocatalytic degradation of RhB solution, it was found that the photocatalytic properties of the composites were higher than those of the pure materials, especially when the content of PANI is 3%, the photocatalytic effect is the best, which is 3.8 times of pure PbBiO2Br. This is due to the unique electrical properties of PANI itself, the synergistic effect between PANI and PbBiO2Br, and the influence of the low recombination efficiency of electron-hole pairs. The study of the mechanism indicatesr hatcess, respectively that hydroxyl radical is the main group that influences the photocatalytic degradation of RhB solution, and the hole (h+) plays an important role.(2) A new type of stable and ultra thin 2D heterostructure composites PbBiO2Br/g-C3N4 was successfully prepared by solvothermal method. Compared with pure materials, this kind of structure can improve the photocatalytic activity. When the ratio of PbBiO2Br and g-C3N4 was 1:1, its K (first order photodegradation kinetic constant) was 3.83 and 4.13 times of PbBiO2Br and g-C3N4. The main reason is that the ultrathin PbBiO2Br and 2D g-C3N4 form a heterojunction structure,which can effectively promote the transport and separation of photogenerated electron-hole pairs.In the process of photodegradation of RhB solution, (h+) and O2·- are the main active components, and the composite photocatalyst has good structural stability and regeneration ability.(3) The heterojunction structure of PbBiO2Br/UiO-66-NH2 was successfully prepared by a simple solvothermal method. The colorless phenol and colored RhB dye degradation under visible light irradiation was used to evaluate the activity of the catalyst, and it can be concluded that the heterojunction structure of composite exhibits higher catalytic activity compared with pure materials. When the ratio of PbBiO2Br to UiO-66-NH2 was 3:2, the photodegradation of RhB and phenol solution was the best. In exploring the mechanism of photocatalytic degradation of RhB solution,it was found that the (h+) and O2·- are the main active components.