Design,Synthesis And Performance Control Of Highly Effective Bismuth-based Photocatalytic Materials

The research and development of high-performance Bismuth-based photocatalytic materials have important scientific and practical values for solving the increasingly serious environmental pollution and clean energy crisis.However,it has been reported that Bismuth-based photocatalytic materials generally have low photo-generated charge separation efficiency and poor photocatalytic activity and stability due to their own structural and functional defects.Studies have shown that the microstructure of the material?morphology,size,dimension,crystal surface,specific surface,etc.?is closely related to the photocatalytic properties.Therefore,we have regulated the microstructure of the material by designing different synthetic routes.The specific work is as follows:Construction of hierarchical structure assembled by ultrathin nanosheet is one of the important challenges in material chemistry and photocatalytic field,because this kind of material can combine the advantages of hierarchical structure and ultrathin material.Herein,we propose an ion-exchange approach to the fabrication of novel hierarchical porous Bi₂₄O₃₁Br₁₀ microstructures assembled by ultrathin nanosheets with thicknesses of 3-5 nm through a facile reflux process,employing previously-prepared Bi₂₅VO₄₀ micro-cubes as precursors of Bi³⁺ions.Experiments revealed that the Bi₂₄O₃₁Br₁₀ hierarchical structures possessed a high surface area?⁶7.16 m²/g?and abundant mesopores,leading to the strong adsorption capacity for rhodamine B?RhB?with high concentration.The maximal adsorption quantity of the product was calculated to be 24.4 mg/g.Photocatalytic results demonstrated that the as-prepared Bi₂₄O₃₁Br₁₀ sample exhibited a significant structure-induced enhancement of photocatalytic performance.After 12 min of UV-visible-light irradiation,96%of RhB solution?40 mg/L?could be completely decomposed.In addition,the trapping experiments confirmed that photo-generated hole was believed as the chief active specie in the degradation process of RhB molecule.Fabrication of noble-metal nanoparticle decorated hierarchical heterostructure photocatalyst composed of ultrathin nanoflake can be considered as one of the most effective approach for enhancing the photocatalytic performance due to its unique micro-scale structure and functional combination.Therefore,we report the successful preparation of Ag nanoparticle-decorated biscuit-like Bi₂₄O₃₁Cl₁₀hierarchical microstructure through a facile solution-phase synthesis route.Experiment indicated that the Bi₂₄O₃₁Cl₁₀ product was comprised of ultrathin nanoflake with thickness of 5-10 nm.After introducing Ag nanoparticle,the as-obtained Ag-Bi₂₄O₃₁Cl₁₀ nanocomposite exhibited improved photocatalytic performance for the decolorization of rhodamine B in comparison to pure Bi₂₄O₃₁Cl₁₀ sample.The amount of Ag in the heterostructure photocatalyst significantly influenced the photocatalytic efficiency,and 4 wt%Ag exhibited the best photocatalytic performance.In addition,an enhanced mechanism of photodegradation activity over Ag nanoparticle-decorated biscuit-like Bi₂₄O₃₁Cl₁₀hierarchical microstructure was proposedConstruction of doped-type semiconductor-based photocatalysts can be considered as an excellent platform for enhancing photocatalytic performance owing to their unique properties such as excellent light-absorption ability,more reactive sites and increased photo-induced charge transfer capability.Therefore,we propose a facile hydrothermal synthesis route for the construction of Fe³⁺doped Bi₂Mo₂O₉ultrathin nanosheet with thicknesses of⁴ nm.Experimental result indicated that the introduction of Fe³⁺into the Bi₂Mo₂O₉ lattice could enhance the light absorption ability and narrow the band-gap of the final product.Photocatalytic results showed that the Fe³⁺doped Bi₂Mo₂O₉ ultrathin nanosheet exhibited enhanced photocatalytic activity for the decomposition of organic dye such as Rhodamine B?RhB?compared with pure Bi₂Mo₂O₉.Moreover,an enhanced mechanism of photocatalytic performance over Fe³⁺doped Bi₂Mo₂O₉ ultrathin nanosheet was investigated and proposed.