Search

At present, most common catalysts are faced with the problem of high cost and only visible light response. Graphitic carbon nitride (g-C 3 N 4) consists of elements C and N that are sufficiently abundant in the world and has visible light responses, but the electron-hole recombination rate of this photocatalyst is high. In this work, we directly prepare a series of g-C 3 N 4 -bismuth oxyhalides composites via facile in-situ deposition. Bismuth oxides with different chloro-iodine ratios (BiOCl x I 1-x) are prepared, followed by g-C 3 N 4 deposition, setting up interfaces and improving photogenic charge carriers transfer. By testing the compositions, Cl:I = 8:2 in BiOCl x I 1-x and 10% of g-C 3 N 4 doping amount enable the best photocatalytic performance of the samples. Under visible light irradiation, the degradation rate of rhodamine B (RhB) reaches 99% within 40 min. Through a variety of tests, the photogenerated hole (h+) and superoxide radical (•O 2 −) are found to play key roles in the degradation process. Cl element doping and heterojunction building improve the photocatalysis capacity of g-C 3 N 4 and broaden the visible-light response of pure BiOI. [ABSTRACT FROM AUTHOR]

In this work, Bi 4 O 5 I 2 -Bi 2 O 2 CO 3 -BiOCl 0.8 I 0.2 n-p-n heterojunction was synthesized by in-situ growth method. Different types of BiOX (X = Br, Cl and I) materials were combined to optimize the charge separation of prepared heterogeneous junction so as to improve the photocatalytic performance. It had been proved by various characterization methods that the charge carrier recombination would be greatly suppressed under the action of internal electric field at the interface when n-p-n heterojunction was formed. Specially, 20-Bi 4 O 5 I 2 -Bi 2 O 2 CO 3 -BiOCl 0.8 I 0.2 presented the best photocatalytic performance, which could degrade 99% of Rhodamine B (RhB) in 60 min under 500 W Xe lamp source. BiOCl 0.8 I 0.2 improves the performance of photocatalytic and broaden the light absorption range of pure BiOI. This work provides a new perspective to design ternary structures that enhance photocatalytic performance. [Display omitted] [ABSTRACT FROM AUTHOR]

Bi 4 O 5 I 2 /Bi 2 O 2 CO 3 p-n heterojunction photocatalysts were synthesized by utilizing different ratios of solvent via a one-pot solvothermal method in the process of synthesizing Bi 4 O 5 I 2 and Bi 5 O 7 I. The structure, morphology and photoelectric properties of the prepared samples were characterized by XRD, SEM, TEM, FTIR, XPS and DRS. Through the estimated photocatalytic degradation of pollutants such as tetracycline hydrochloride (TC) and rhodamine B (RhB), it was found that the Bi 4 O 5 I 2 /Bi 2 O 2 CO 3 (the ratio of ethylene glycol and distilled water in the solvent was 3/5) heterojunction photocatalyst had the highest degradation, with the removal of up to 80.6% from all prepared samples within 30 min under visible light irradiation; this heterojunction also showed better RhB degradation performance. The presence of an internal electrostatic field between the p-type semiconductor Bi 4 O 5 I 2 and n-type semiconductor Bi 2 O 2 CO 3 effectively suppressed the recombination of photoinduced electron–hole pairs. Moreover, a feasible mechanism was proposed. [ABSTRACT FROM AUTHOR]

• A photocatalyst was constructed by combining direct Z-scheme and isotype heterojunction. • A ternary Δ(Z + H)-scheme g-C 3 N 4 /g-C 3 N 4 /BiOBr photocatalyst is prepared by an effective combination of thermal decomposition and solvothermal method. • Solar light utilization can be enhanced in ternary Δ(Z + H)-scheme g-C 3 N 4 /g-C 3 N 4 /BiOBr. • The composites is wide application in the degradation of organic pollutants (RhB, FITC and TC), which potential to be applied as a photocatalyst for wastewater treatment. A novel ternary direct Z-scheme + isotype heterojunction, Δ(Z + H)-scheme photocatalyst CN-TU/BiOBr was fabricated by an effective combination of thermal decomposition and solvothermal method. The samples of g-C 3 N 4 prepared using urea, thiourea and thiourea-urea complexes as precursors were named CN-U, CN-T and CN-TU, respectively. In addition, CN-M was prepared by physically mixing CN-U and CN-T. The structure, morphology, optical and electronic properties of the prepared samples were characterized by XRD, FTIR spectra, SEM-EDS, BET, XPS and DRS. The photocatalytic activities of the synthesized samples were estimated by the degradation of Rhodamine B (RhB), Fluorescein isothiocyanate (FITC) and antibiotic tetracycline hydrochloride (TC) in the presence of visible light. Compared with other as-prepared samples, the ternary 1%CN-TU/BiOBr photocatalyst exhibited an excellent activity, which is attributed to the construction of the ternary Δ(Z + H)-scheme not only benefit to maintain outstanding redox capability of the electrons, but also facilitates the separation of photo-generated carrier. Furthermore, the stability of the sample is tested by cyclic experiments. This work will provided a new insight into optimizing the structure and designing similar Z-scheme photocatalytic system. [ABSTRACT FROM AUTHOR]