Bi4O5I2 Nanosheets Research Articles

Facet-Dependent Photocatalytic N2 Fixation of Bismuth-Rich Bi5O7I Nanosheets

Bismuth-rich bismuth oxyhalides (Bi-O-X; X = Cl, Br, I) display high photocatalytic reduction activity due to the promoting conduction band potential. In this work, two Bi5O7I nanosheets with different dominant facets were synthesized using either molecular precursor hydrolysis or calcination. Crystal structure characterizations, included X-ray diffraction patterns (XRD), field emission electron microscopy and fast Fourier transformation (FFT) images, showed that hydrolysis and calcination resulted in the dominant exposure of {100} and {001} facets, respectively. Photocatalytic data revealed that Bi5O7I-001 had a higher activity than Bi5O7I-100 for N2 fixation and dye degradation. Photoelectrochemical data revealed that Bi5O7I-001 had higher photoinduced carrier separation efficiency than Bi5O7I-100. The band structure analysis also used to explain the underlying photocatalytic mechanism based on the different conduction band position. This work presents the first report about the facet-dependent photocatalytic performance of bismuth-rich Bi-O-X photocatalysts.

Construction of ultrathin C3N4/Bi4O5I2 layered nanojunctions via ionic liquid with enhanced photocatalytic performance and mechanism insight

A novel visible-light-driven ultrathin C3N4/Bi4O5I2 layered nanojunctions photocatalyst was prepared via a facile solvothermal method in the presence of reactable ionic liquid 1-hexyl-3-methylimidazolium iodide ([Hmim]I). 1-hexyl-3-methylimidazolium iodide was served as I source, template and dispersing agent at the same time, which favored the formation of Bi4O5I2 ultrasmall nanostructure and good dispersivity among the ultrathin C3N4. A series of characterizations were employed to probe the structure, morphology, optical and electronic characteristics of the obtained ultrathin C3N4/Bi4O5I2 layered nanojunctions. Experiment results show that the ultrasmall Bi4O5I2 nanosheets were dispersed on the surface of ultrathin C3N4 uniformly and the compact heterostructures were constructed. The photocatalytic performance of the as-prepared samples was evaluated by the degradation of rhodamine B (RhB) and colorless endocrine disrupting chemical bisphenol A (BPA) under visible light irradiation. The ultrathin C3N4/Bi4O5I2 layered nanojunctions displayed much higher photocatalytic activity than the pure Bi4O5I2, in addition, 3wt% ultrathin C3N4/Bi4O5I2 exhibited the highest activity. The enhancement of photocatalytic activity was ascribed to the well-distribution for ultrasmall Bi4O5I2 nanosheets on the ultrathin C3N4 surface and the formation of closely heterostructures that could favor the transfer and separation of photogenerated charge carriers. A possible photocatalytic mechanism based on the matched energy band structure and action mechanism of active species was proposed.

G-C3N4/Bi4O5I2 2D–2D heterojunctional nanosheets with enhanced visible-light photocatalytic activity

The 2D–2D heterojunctional g-C3N4/Bi4O5I2 nanosheets were successfully constructed based on band gap engineering design. It exhibits high visible-light-driven photocatalytic activity for degradation of RhB and NO removal.

Preparation and photocatalytic activity of porous Bi5O7I nanosheets

Porous Bi5O7I nanosheets were successfully prepared by a facile thermal decomposition of BiOI nanosheets in air at 500°C for 2h. The crystal structure, surface morphology, specific surface area, and optical properties of resulted materials were characterized by XRD, SEM, TEM, nitrogen adsorption–desorption isotherms and UV–vis diffuse reflectance spectroscopy, respectively. Moreover, the photodegradation ability of porous Bi5O7I nanosheets on target pollutant Rhodamine B (RhB) under visible light irradiation (λ≥400nm) and simulated sunlight irradiation was investigated. The results indicated that porous Bi5O7I nanosheets were mainly composed of irregular nanosheets. With the layer thickness of 30–50nm and pore diameter distribution around 25nm, it belonged to mesoporous material. Compared with BiOI, the photocatalytic activity of porous Bi5O7I nanosheets under visible light was appropriately 2 times than that of BiOI, and 2.3 times under simulated sunlight. The major reasons for the improvement in catalytic performance were the existence of multiple pores and the special band structure.