Synthesis of Oxygen-Rich Bismuth Oxybromide (Bi24O31Br10) Photocatalyst for High Efficiency Degradation of Sulfadiazine Under Simulated Sunlight

At present, compared with other antibiotic degradation systems, there are few literatures on pho- tocatalytic degradation of sulfadiazine (SDZ). In this research, it was firstly discovered that the oxygen-rich bismuth oxybromide (Bi24O31 Br10) photocatalyst can efficiently degrade SDZ under simulated sunlight. In this paper, the prepared Bi24O31Br10 photocatalyst by mixed solvothermal method represented outstanding photocatalytic performance. The catalyst synthesized at 120 °C and pH = 10 showed optimum degradation function in the samples prepared at various temperatures and pH value. After 3 h of irradiation, 96.2% of SDZ solution could be decomposed. The effects of preparation conditions, catalyst dosage, initial SDZ concentration and initial SDZ pH value on photocatalytic degradation efficiency were investigated systematically. Besides, the effect of active species was studied by trapping tests, and it was concluded that ‘O2 contributes the most to the photocatalytic process. A possible photocatalytic degradation mechanism was proposed.

Photocatalytic Degradation of Composites With Magnesium Aluminum Hydrotalcite Derived Metal Oxides and g-C3N4

The remove of the organic pollutants in water plays an important role on the environmental protection, thus photocatalysis, as an effective method, has been attained much attention to deal with this problem. In this paper, a composite of g-C3N4 and Mg-Al hydrotalcite derived metal oxides was prepared to degrade these organic pollutants by simple calcination and co-precipitation methods. And Mg-Al hydrotalcite derived metal oxides were successfully coated on the surface of g-C3N4. The photocatalytic degradation rate of methylene blue reached 97.3% within 1h under visible light, and the degradation rate constant was 0.0432min-1, which is 3.6 times that of g-C3N4. In the recycling process of the catalyst, the good stability of photocatalytic degradation was found. Though characterization analysis, more active sites are exposed to absorb more organic pollutants on the mater surface in the presence of the interinserted and coated structures of composite materials, and the "face to face" contact structure between 2D materials is formed to promote the separation of photogenerated carriers. In addition, the photocatalytic degradation mechanism of the catalyst was explained by free radical scavenging experiment. The material provides an effective method for removing organic pollutants in water, and has broad application prospects.

The facile preparation of porphyrin based hierarchical micro/nano assemblies and their visible light photocatalytic activity

Porphyrin nanostructures are widely used in the field of visible light catalysis due to their superior light absorption properties and good controllability in size, shape and function. In this paper, the development of various morphologies in three types of porphyrins with three different phenyl substituents (designated as H2TTP, H2TPP and H2TCPP, respectively) is demonstrated. The formation mechanism proposed was based on the evolution of morphology as functions of molecular structure and solvent mixture. These nano/micro assemblies are well characterized by SEM, IR, UV-vis, X-ray diffraction and photoelectric conversion. The photocatalytic oxidation reactions under visible light irradiation of 1,5-dihydroxynaphthalene (DHN) in water is utilized to evaluate the photoactivity of the as-prepared porphyrin assemblies. The photocatalytic results indicate that the obtained porphyrin assemblies exhibit enhanced visible-light photocatalytic activity. In addition, the photocatalyst is easy to separate and recover, and has good stability. The possible photocatalytic degradation mechanism of DHN by the porphyrins nanopolyhedron photocatalyst was also proposed.

Enhanced Photocatalytic Activity of Agbr Photocatalyst via Constructing Heterogeneous Junctions With Reduced Graphene

A series of rGO/AgBr heterojunction photocatalysts were fabricated through a facile solvothermal method. The rGO/AgBr heterostructures were characterized by XPS, XRD, UV-Vis DRS, SEM, TEM, PL and the transient photocurrent responses. The XRD, SEM, XPS and TEM analyzes indicated that the graphene and silver bromide were successfully compounded without other impurities. The UV-Vis DRS exhibited that the composites have better optical properties than pure silver bromide. The PL and the transient photocurrent responses demonstrated that the addition of graphene significantly promotes the separation of photogenerated electrons and holes. Subsequently, the photocatalytic activities of rGO/AgBr composites were studied by degrading Rhodamine B (RhB). It turned out that the degradation rate of RhB by the rGO/AgBr heterojunction photocatalysts were significantly higher than that by pure AgBr. What’s more, to study the photocatalytic degradation mechanism of RhB by rGO/AgBr heterostructures, the trapping experiments were used to identify the main active components. This work confirmed that the photocatalytic degradation performance of the catalyst was greatly improved after doping graphene, which provided certain data support for degradation of organic contaminants in water.