Flower-like Bi2SiO5/Bi4MoO9 heterostructures for enhanced photocatalytic degradation of ciprofloxacin

High-Throughput Strategies for the Design, Discovery, and Analysis of Bismuth-Based Photocatalysts

Bismuth-based nanostructures (BBNs) have attracted extensive research attention due to their tremendous development in the fields of photocatalysis and electro-catalysis. BBNs are considered potential photocatalysts because of their easily tuned electronic properties by changing their chemical composition, surface morphology, crystal structure, and band energies. However, their photocatalytic performance is not satisfactory yet, which limits their use in practical applications. To date, the charge carrier behavior of surface-engineered bismuth-based nanostructured photocatalysts has been under study to harness abundant solar energy for pollutant degradation and water splitting. Therefore, in this review, photocatalytic concepts and surface engineering for improving charge transport and the separation of available photocatalysts are first introduced. Afterward, the different strategies mainly implemented for the improvement of the photocatalytic activity are considered, including different synthetic approaches, the engineering of nanostructures, the influence of phase structure, and the active species produced from heterojunctions. Photocatalytic enhancement via the surface plasmon resonance effect is also examined and the photocatalytic performance of the bismuth-based photocatalytic mechanism is elucidated and discussed in detail, considering the different semiconductor junctions. Based on recent reports, current challenges and future directions for designing and developing bismuth-based nanostructured photocatalysts for enhanced photoactivity and stability are summarized.

Bi metal/oxygen-deficient BiO2-x with tetrahedral morphology and high photocatalytic activity

Vacancy-rich materials with high photocatalytic activity are of great interest for pollutants removal and play a significant role in green chemistry. Herein, we successfully synthesized Bi/BiO_2-x composite through hydrothermal route. In this case, the surface plasmon resonance effect of Bi and oxygen vacancies of BiO_2-x collectively increase the removal rate of pollutants. More importantly, the Bi/BiO_2-x composites have enhanced activity in the degradation of RhB, MO, BPA and CIP, and the reduction of Cr(VI) and PNA. Besides, an enhanced photocatalytic activity is due to the main reactive species of ·[Formula: see text] and h⁺ that is confirmed by trapping experiments and ESR analyses. The electronic structure and visible light harvesting of photocatalysts were measured and also theoretically calculated by using density functional theory and finite difference time domain calculations, DRS, VB x-ray photoelectron spectroscopy and Mott-Schottky plots, which allowed to propose a possible photocatalytic mechanism for the degradation process.

Hydrothermal synthesis of a CoIn2S4/g-C3N4 heterojunctional photocatalyst with enhanced photocatalytic H2 evolution activity under visible light illumination

CoIn₂S₄, a black semiconducting material, possesses an outstanding visible light response and is employed to modify g-C₃N₄. A series of CoIn₂S₄/g-C₃N₄ heterojunctional photocatalysts are synthesized via a hydrothermal method, whereby cubic CoIn₂S₄ nanosheets are in situ immobilized on the surfaces of porous g-C₃N₄ nanosheets. Compared with the pristine g-C₃N₄ and CoIn₂S₄, under visible light (λ > 420 nm) irradiation, the CoIn₂S₄/g-C₃N₄ composite samples show markedly enhanced photocatalytic activity in hydrogen evolution. Among all of the samples, the 30% CoIn₂S₄/g-C₃N₄ sample shows the maximum H₂ evolution rates, 5.2 and 23.9 times higher than those of g-C₃N₄ and CoIn₂S₄, respectively. The efficient photocatalytic activity of CoIn₂S₄/g-C₃N₄ composite photocatalysts is attributed to the formation of an intimate heterostructure, which not only significantly facilitates charge migration, but also enhances visible light absorption. Moreover, a plausible photocatalytic mechanism for the composite photocatalyst has been elucidated. This research provides a novel hint for fabricating visible-light-responsive heterojunction photocatalysts with high performance for energy production.