Z-Scheme Cu2O/Bi/BiVO4 Nanocomposite Photocatalysts: Synthesis, Characterization, and Application for CO2 Photoreduction

Construction of Ultrathin BiVO4-Au-Cu2O Nanosheets with Multiple Charge Transfer Paths for Effective Visible-Light-Driven Photocatalytic Degradation of Tetracycline

In this study, unique BiVO4-Au-Cu2O nanosheets (NSs) are well designed and multiple charge transfer paths are consequently constructed. The X-ray photoelectron spectroscopy measurement during a light off-on-off cycle and redox capability tests of the photo-generated charge carriers confirmed the formation of Z-scheme heterojunction, which can facilitate the charge carrier separation and transfer and maintain the original strong redox potentials of the respective component in the heterojunction. The ultrathin 2D structure of the BiVO4 NSs provided sufficient surface area for the photocatalytic reaction. The local surface plasmon resonance (LSPR) effect of the electron mediator, Au NPs, enhanced the light absorption and promoted the excitation of hot electrons. The multiple charge transfer paths effectively promoted the separation and transfer of the charge carrier. The synergism of the abovementioned properties endowed the BiVO4-Au-Cu2O NSs with satisfactory photocatalytic activity in the degradation of tetracycline (Tc) with a removal rate of ≈80% within 30 min under visible light irradiation. The degradation products during the photocatalysis are confirmed by using ultra-high performance liquid chromatography-mass spectrometry and the plausible degradation pathways of Tc are consequently proposed. This work paves a strategy for developing highly efficient visible-light-driven photocatalysts with multiple charge transfer paths for removing organic contaminants in water.

Photocatalytic Enhancement Strategy with the Introduction of Metallic Bi: A Review on Bi/Semiconductor Photocatalysts

Semiconductor photocatalysis has great potential in the fields of solar fuel production and environmental remediation. Nevertheless, the photocatalytic efficiency still constrains its practical production applications. The development of new semiconductor materials is essential to enhance the solar energy conversion efficiency of photocatalytic systems. Recently, the research on enhancing the photocatalytic performance of semiconductors by introducing bismuth (Bi) has attracted widespread attention. In this review, we briefly overview the main synthesis methods of Bi/semiconductor photocatalysts and summarize the control of the micromorphology of Bi in Bi/semiconductors and the key role of Bi in the catalytic system. In addition, the promising applications of Bi/semiconductors in photocatalysis, such as pollutant degradation, sterilization, water separation, CO2 reduction, and N2 fixation, are outlined. Finally, an outlook on the challenges and future research directions of Bi/semiconductor photocatalysts is given. We aim to offer guidance for the rational design and synthesis of high-efficiency Bi/semiconductor photocatalysts for energy and environmental applications.

Supported photocatalyst for Cr (VI) conversion and removal of organic pollutants

The photocatalytic property of available semiconductor catalysts still suffers from some urgent problems, such as the high excitation energy, easy agglomeration of powders, or weak recycling property. Therefore, developing novel visible light-supported catalysts and catalyst loading have aroused great attention recently. In this work, a novel Ag₃PO₄/BiVO₄/MWCNTs@Cotton functional fabric was prepared by introducing Ag₃PO₄ as a plasma resonance photocatalyst and MWCNTs with cotton as composite substrates. Not only did the introduction of Ag₃PO₄ and MWCNTs effectively strengthen the application ability of BiVO₄, but also inhibited the recombination of carriers, and promoted the transport of carriers according to spectroscopic and electrochemical tests. Degradation tests remained that Ag₃PO₄/BiVO₄/MWCNTs @cotton retained the high photocatalytic efficiency of the powder catalyst, along with the degradation degree of active blue KN-R (50mg/L) as well as Cr (VI) (20mg/L) could reach more than 90% within 120 min. What's more, the functional fabric has gained excellent performance in degrading pollutants for 5 cycles. Meanwhile, the prepared BiVO₄ is consistent with the band structure and electron density calculated theoretically by the GGA-PBE function. Free radical trapping and scavenging experiments exhibited that functional fabrics could produce active substances such as h⁺,·O₂^-, and·OH, among which the first two are the main active substances in the reaction. To sum up, this study is an effective attempt based on the existing problems of photocatalysts together with providing some study directions for the development of photocatalytic technology in the future.