Enhancement in the photocatalytic antifouling efficiency over cherimoya-like InVO4/BiVO4 with a new vanadium source

Fe-Bi dual sites regulation of Bi2O2.33 nanosheets to promote photocatalytic nitrogen fixation activity

In the process of photocatalytic ammonia synthesis, efficient activation of nitrogen molecules constitutes a fundamental challenge. During the N2 activation, the close interdependence between the acceptance and donation of electron results in their mutual limitation, leading to high energy barrier for N2 activation and unsatisfactory photocatalytic performance. This work decoupled the electron acceptance and donation processes by constructing Fe-Bi dual active sites, resulting in enhancing N2 activation through the high electron trapping ability of Fe3+ and strong electron donating ability of Bi2+. The photocatalytic nitrogen reduction efficiency of 3%Fe/Bi2O2.33 (118.71 μmol gcat-1h-1) is 5.3 times that of Bi2O2.33 (22.41 μmol gcat-1h-1). In-situ Fourier transform infrared (In situ FTIR) spectroscopy and density functional theory (DFT) calculations manifest that Fe3+-Bi2+ dual active sites work together to promote nitrogen adsorption and activation, and the reaction path is more inclined toward alternate hydrogenation path. N2 adsorption and activation properties are optimized by heteronuclear bimetallic active sites, which offers a new way for the rational design of nitrogen-fixing photocatalysts.

Recent progress on bismuth-based light-triggered antibacterial nanocomposites: Synthesis, characterization, optical properties and bactericidal applications

Bacterial infections pose a seriously threat to the safety of the environment and human health. In particular, the emergence of drug-resistant pathogens as a result of antibiotic abuse and high trauma risk has rendered conventional therapeutic techniques insufficient for treating infections by these so-called "superbugs". Therefore, there is an urgent need to develop highly efficient and environmentally-friendly antimicrobial agents. Bismuth-based nanomaterials with unique structures and physicochemical characteristics have attracted considerable attention as promising antimicrobial candidates, with many demonstratingoutstanding antibacterial effects upon being triggered by broad-spectrum light. These nanomaterials have also exhibited satisfactory energy band gaps and electronic density distribution with improved photonic properties for extensive and comprehensive applications after being modified through various engineering methods. This review summarizes the latest research progress made on bismuth-based nanomaterials with different morphologies, structures and compositions as well as the different methods used for their synthesis to meet their rapidly increasing demand, especially for antibacterial applications. Moreover, the future prospects and challenges regarding the application of these nanomaterials are discussed. The aim of this review is to stimulate interest in the development and experimental transformation of novel bismuth-based nanomaterials to expand the arsenal of effective antimicrobials.

Novel Indium Vanadium Oxide Nanosheet-Supported Nickel Iron Oxide Nanoplate Heterostructure for Synergistically Enhanced Photocatalytic Degradation of Tetracycline

Semiconductor-based heterogeneous photocatalytic oxidation processes have received considerable attention for the remediation of toxic pollutants. Herein, InVO4/NiFe2O4 nanocomposites were synthesized using a facile hydrothermal technique. Furthermore, various characterization results revealed the successful loading of NiFe2O4 nanoplates over InVO4 nanosheets, thereby signifying the formation of a heterostructure. The performance of the synthesized photocatalyst was tested for tetracycline (TC) antibiotic removal. The optimized InVO4/NiFe2O4 nanocomposite exhibits maximum photodegradation of TC molecules (96.68%) in 96 min; this is approximately 6.47 and 4.93 times higher than that observed when using NiFe2O4 and InVO4, respectively. The strong interaction between the InVO4 nanosheets and NiFe2O4 nanoplates can improve the visible-light absorption and hinder the recombination of charge carriers, further enhancing the photocatalytic performance. Moreover, hydroxyl radicals play a crucial role in the photodegradation of TC antibiotics.

Application of nanostructures as antimicrobials in the control of foodborne pathogen

Foodborne pathogens are the main cause of human foodborne diseases and pose a serious threat to food safety. The control of them has always been a significant issue in food industry. With good biocompatibility and stability, nanomaterials display excellent bactericidal properties against many kinds of bacteria. In this review, the generation and application of nanostructures as antibacterial in the control of foodborne pathogens was summarized. The antibacterial effects of photocatalytic and contact bacteriostatic nanomaterials agents were mainly introduced. The influence factors and mechanisms of nanomaterials on the inactivation of foodborne pathogens were displayed. The photocatalytic nanostructured bacteriostatic agents can produce reactive oxygen species (ROS) and lead to charge transfer, which result in damaging of cell wall and leakage of small molecules under light irradiation. In addition, metals and metal oxide nanoparticles can kill bacterial cells by releasing metal ions, forming ROS and electrostatic interaction with cell membrane. Besides, the synergistic action of nanoparticles with natural antibacterial agents can improve the stability of these agents and their bactericidal performance. These current researches provided a broader idea for the control of microorganisms in food.

Research progress of environmentally friendly marine antifouling coatings

The antifouling mechanisms and research progress in the past three years of environmentally friendly marine antifouling coatings are introduced in this work.

Microwave-Assisted Synthesis and Characterization of Solar-Light-Active Copper–Vanadium Oxide: Evaluation of Antialgal and Dye Degradation Activity

In this work, solar-light-active copper–vanadium oxide (Cu-VO) was synthesized by a simple microwave method and characterized by FESEM, EDS, XRD, XPS, UV–Vis/near-infrared (NIR), and FT-IR spectroscopy. Antialgal and dye degradation activities of Cu-VO were investigated against Microcystis aeruginosa and methylene blue dye (MB), respectively. The mechanism of action of Cu-VO was examined regarding the production of hydroxyl radical (·OH) in the medium and intracellular reactive oxygen species (ROS) in M. aeruginosa. FESEM and XRD analyses of Cu-VO disclosed the formation of monoclinic crystals with an average diameter of 132 nm. EDX and XPS analyses showed the presence of Cu, V, and O atoms on the surface of Cu-VO. Furthermore, FT-IR analysis of Cu-VO exposed the presence of tetrahedral VO4 and octahedral CuO6. Cu-VO effectively reduced the algal growth and degraded methylene blue under solar light. A total of 4 mg/L of Cu-VO was found to be effective for antialgal activity. Cu-VO degraded 93% of MB. The investigation of the mechanism of action of Cu-VO showed that ·OH mediated antialgal and dye degradation of M. aeruginosa and MB. Cu-VO also triggered the production of intracellular ROS in M. aeruginosa, leading to cell death. Thus, Cu-VO could be an effective catalyst for wastewater treatment.

Fabrication of a Novel AgBr/Ag2MoO4@InVO4 Composite with Excellent Visible Light Photocatalytic Property for Antibacterial Use

A novel AgBr/Ag2MoO4@InVO4 composite photocatalyst with different heterojunction structures was successfully constructed by compounding InVO4 with Ag2MoO4 and AgBr. According to the degradation, antibacterial and free radical trapping data, the photocatalytic antibacterial and antifouling activities of AgBr/Ag2MoO4@InVO4 composite were evaluated, and the corresponding photocatalytic reaction mechanism was proposed. Adding AgBr/Ag2MoO4@InVO4 composite, the degradation rate of ciprofloxacin (CIP) achieved 95.5% within 120 min. At the same time, the antibacterial rates of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) achieved 99.99%. The AgBr/Ag2MoO4@InVO4 composite photocatalyst showed promising usage in photocatalytic antibacterial and purification areas.

Phytosynthesis of BiVO4 nanorods using Hyphaene thebaica for diverse biomedical applications

Biosynthesis of bismuth vanadate (BiVO₄) nanorods was performed using dried fruit extracts of Hyphaene thebaica as a cost effective reducing and stabilizing agent. XRD, DRS, FTIR, zeta potential, Raman, HR-SEM, HR-TEM, EDS and SAED were used to study the main physical properties while the biological properties were established by performing diverse assays. The zeta potential is reported as − 5.21 mV. FTIR indicated Bi–O and V–O vibrations at 640 cm⁻¹ and 700 cm⁻¹/1120 cm⁻¹. Characteristic Raman modes were observed at 166 cm⁻¹, 325 cm⁻¹ and 787 cm⁻¹. High resolution scanning and transmission electron micrographs revealed a rod like morphology of the BiVO₄. Bacillus subtilis, Klebsiella pneumonia, Fusarium solani indicated highest susceptibility to the different doses of BiVO₄ nanorods. Significant protein kinase inhibition is reported for BiVO₄ nanorods which suggests their potential anticancer properties. The nanorods revealed good DPPH free radical scavenging potential (48%) at 400 µg/mL while total antioxidant capacity of 59.8 µg AAE/mg was revealed at 400 µg/mL. No antiviral activity is reported on sabin like polio virus. Overall excellent biological properties are reported. We have shown that green synthesis can replace well established processes for synthesizing BiVO₄ nanorods.

The effective photocatalysis and antibacterial properties of AgBr/AgVO3 composites under visible-light

With the discharge of large amount of organic pollutants and antibiotics into the water environment, the water cycle has been seriously polluted, and at the same time, various drug-resistant bacteria have emerged in succession, which poses a serious threat to human health. In recent years, photocatalytic nanomaterials have become a research hotspot in the antimicrobial area. In this study, AgBr/AgVO3 photocatalysts were prepared by a hydrothermal process and an in situ growth method. The composites were tightly connected by the (501) plane of AgVO3 and the (200) lattice plane of AgBr. The photocatalytic activity was tested by degrading Rhodamine B (RhB) solution under visible-light, and the result indicated that the photodegradation rate for RhB solution was 92.3% by the photocatalysis with 0.5AgBr/AgVO3 and the photocatalytic performance of 0.5AgBr/AgVO3 was improved compared to pure AgVO3 and AgBr. In addition, more than 99.997% of E. coli, S. aureus, and P. aeruginosa cells were killed by the photocatalysis with 0.5AgBr/AgVO3 within 30 min. These results demonstrated that the 0.5AgBr/AgVO3 heterojunction photocatalyst could be widely used in the treatment of environmental pollution and in the antibacterial field.

Preparation of a novel Z-scheme KTaO3/FeVO4/Bi2O3 nanocomposite for efficient sonocatalytic degradation of ceftriaxone sodium

In this work, a novel Z-scheme sonocatalyst, KTaO₃/FeVO₄/Bi₂O₃, is prepared via ultrasonic-assisted isoelectric point method. The prepared samples are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) spectroscopy. The catalytic activity of Z-scheme KTaO₃/FeVO₄/Bi₂O₃ sonocatalyst is studied in degradation of ceftriaxone sodium under ultrasonic irradiation. In addition, the influences of ultrasonic irradiation time, scavengers and sonocatalyst used times on sonocatalytic degradation of ceftriaxone sodium are examined. Under the experimental conditions of 150 min ultrasonic irradiation time, 1.00 g/L KTaO₃/FeVO₄/Bi₂O₃ addition amount and 10.00 mg/L ceftriaxone sodium concentration, the sonocatalytic degradation ratio of ceftriaxone sodium achieves 81.30%. Finally, the possible sonocatalytic degradation mechanism of ceftriaxone sodium caused by Z-scheme KTaO₃/FeVO₄/Bi₂O₃ sonocatalyst is proposed. The enhanced sonocatalytic activity may be attributed to the fact that the FeVO₄ as a special conductive channel provides a strong driving force to transfer electrons through valence state changes of iron and vanadium, which accelerates electron transfer from conduction band (CB) of Bi₂O₃ to valence band (VB) of KTaO₃. Perhaps, the KTaO₃/FeVO₄/Bi₂O₃ composite is an excellent Z-scheme sonocatalyst which can be used to effectively degrade the organic pollutants in wastewater under ultrasonic irradiation.

The effective photocatalysis and antibacterial properties of AgBr/Ag2MoO4@ZnO composites under visible light irradiation

A novel Z-scheme AgBr/Ag₂MoO₄@ZnO photocatalyst was fabricated via a hydrothermal process and in situ growth method. X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy were used to determine the structure of the photocatalyst. The results showed that the composites were tightly connected by the (101) lattice plane of ZnO, the (222) plane of Ag₂MoO₄ and the (200) lattice plane of AgBr. Because of the strong redox activity and good separability of photoelectrons and holes induced by the Z-scheme structure, the photodegradation rate for ciprofloxacin (CIP) solution was 80.5% by the photocatalysis of 0.5 AgBr/Ag₂MoO₄@ZnO. In addition, more than 99.999% of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa cells were killed within 60 min. These results demonstrate that AgBr/Ag₂MoO₄@ZnO is a promising photocatalyst, which can be used in organic pollutant degradation and the photocatalytic antibacterial area.