Synthesis of Bi₂S₃/BiVO₄ Heterojunction with a One-Step Hydrothermal Method Based on pH Control and the Evaluation of Visible-Light Photocatalytic Performance

The band gaps of bismuth vanadate (BiVO₄) and bismuth sulfide (Bi₂S₃) are about 2.40 eV and 1.30 eV, respectively. Although both BiVO₄ and Bi₂S₃ are capable of strong visible light absorption, electron–hole recombination occurs easily. To solve this problem, we designed a one-step hydrothermal method for synthesizing a Bismuth sulfide (Bi₂S₃)/Bismuth vanadate (BiVO₄) heterojunction using polyvinylpyrrolidone K-30 (PVP) as a structure-directing agent, and 2-Amino-3-mercaptopropanoic acid (l-cysteine) as a sulfur source. The pH of the reaction solution was regulated to yield different products: when the pH was 7.5, only monoclinic BiVO₄ was produced (sample 7.5); when the pH was 8.0 or 8.5, both Bi₂S₃ and BiVO₄ were produced (samples 8.0 and 8.5); and when the pH was 9.0, only Bi₂S₃ was produced (sample 9.0). In sample 8.0, Bi₂S₃ and BiVO₄ were closely integrated with each other, with Bi₂S₃ particles formed on the surface of concentric BiVO₄ layers, but the two compounds grew separately in a pH solution of 8.5. Visible-light photocatalytic degradation experiments demonstrated that the degradation efficiency of the Bi₂S₃/BiVO₄ heterojunction was highest when prepared under a pH of 8.0. The initial rhodamine B in the solution (5 mg/L) was completely degraded within three hours. Recycling experiments verified the high stability of Bi₂S₃/BiVO₄. The synthesis method proposed in this paper is expected to enable large-scale and practical use of Bi₂S₃/BiVO₄.

Additive dependent synthesis of bismuth oxybromide composites for photocatalytic removal of the antibacterial agent ciprofloxacin and mechanism insight

Bismuth oxybromide composites obtained with TEOA as additive exhibit the highest photocatalytic degradation for CIP under visible light irradiation.

Defect Engineering of Bismuth Oxyiodide by IO3- Doping for Increasing Charge Transport in Photocatalysis

Defect engineering is regarded as one of the most active projects to monitor the chemical and physical properties of materials, which is expected to increase the photocatalytic activities of the materials. Herein, oxygen vacancies and IO₃^- doping are introduced into BiOI nanosheets via adding NaH₂PO₂, which can impact the charge carrier dynamics of BiOI photocatalysts, such as its excitation, separation, trap, and transfer. These oxygen-deficient BiOI nanosheets display attractive photocatalytic activities of gaseous formaldehyde degradation and methyl orange under visible light irradiation, which are 5 and 3.5 times higher than the BiOI samples, respectively. Moreover, the comodified BiOI also displayed superior cycling stability and can be used for practical application. This work not only develops an effective strategy for fabricating oxygen vacancies but also offers deep insight into the impact of surface defects in enhancing photocatalysis.

A novel heterojunction photocatalyst, Bi2SiO5/g-C3N4: synthesis, characterization, photocatalytic activity, and mechanism

A new type of heterojunction photocatalyst, Bi₂SiO₅/g-C₃N₄, was prepared using a controlled hydrothermal method.

Construction of nitrogen-doped graphene quantum dots-BiVO4/g-C3N4Z-scheme photocatalyst and enhanced photocatalytic degradation of antibiotics under visible light

In this study, an effective nitrogen-doped graphene quantum dots (NGQDs)-BiVO₄/g-C₃N₄Z-scheme heterojunction has been successfully prepared for environmental remediation.