Understanding Reaction Kinetics by Tailoring Metal Co-catalysts of the BiVO4 Photocatalyst

Ultra-sensitive photoelectrochemical biosensor for determination of African swine fever virus based on surface plasmon resonance

Sensitive and specific detection of African swine fever virus (ASFV) is crucial for agricultural production and economic development due to the mortality and infectivity. In this study, a bismuth induced enhanced photoelectrochemical (PEC) biosensor based on in-situ loop mediated isothermal amplification (LAMP) was constructed using deposited bismuth nanoparticles loaded bismuth oxycarbonate (Bi/(BiO)2CO3) as photoactive material, using primers designed according to LAMP as recognition elements, and using in-situ LAMP to achieve nucleic acid amplification of target genes. As the Bi induced surface plasmon resonance (SPR) effect, enhanced light captures and effective electron hole separation, it could effectively enhance the photoelectric activity, so the prepared Bi/(BiO)2CO3 nanohybrid had higher photocurrent intensity and good stability. The constructed PEC biosensor has realized the detection of ASFV in real samples with good sensitivity, specificity and repeatability. In the range from 1.0 × 10-13 to 1.0 × 10-7 g/L, the photoelectric current decreased with the increase of the concentration of ASFV, and the detection limit was 3.0 × 10-14 g/L (about 0.048 copies/μL). Combining the advantages of LAMP with the excellent performance of PEC, it provides a simple, economical and efficient method for nucleic acid diagnosis, and also provides a new idea for biosensor detection.

Bismuth Vanadate (BiVO4) Nanostructures: Eco-Friendly Synthesis and Their Photocatalytic Applications

Green nanotechnology plays an important role in designing environmentally-benign and sustainable synthesis techniques to provide safer products for human health and environments. In this context, the synthesis of bismuth vanadate (BiVO4) nanoparticles (NPs) based on green chemistry principles with the advantages of eco-friendliness, cost-effectiveness, and simplicity has been explored by researchers. Despite the advantages of these synthesis techniques, crucial aspects regarding their repeatability and large-scale production still need to be comprehensively explored. BiVO4 NPs have shown excellent potential in the pharmaceutical industry, cancer therapy, and photocatalysis. BiVO4 particles with monoclinic scheelite structures have been widely investigated for their environmental applications owing to their fascinating optical and electrical properties as well as their high stability and unique crystal structure properties. These NPs with good photostability and resistance to photocorrosion can be considered as promising nanophotocatalysts for degradation of pollutants including organic dyes and pharmaceutical wastes. However, additional explorations should be moved toward the optimization of reaction/synthesis conditions and associated photocatalytic mechanisms. Herein, recent developments regarding the environmentally-benign fabrication of BiVO4 NPs and their photocatalytic degradation of pollutants are deliberated, with a focus on challenges and future directions.

Exploring multifunctional behaviour of g-C3N4 decorated BiVO4/Ag2CO3 hierarchical nanocomposite for simultaneous electrochemical detection of two nitroaromatic compounds and water splitting applications

Development of multifunctional ternary nanocomposite based electrocatalysts for detection of toxic elements and generation of renewable energy describes an environmentally sustainable technique to address the dual challenges of pollution and energy. Herein, we adopted microwave-assisted synthesis to design a multifunctional graphitic carbon nitride (g-C₃N₄) decorated BiVO₄/Ag₂CO₃ (BVG@C) hierarchical ternary nanocomposite for sensing and water splitting applications. The morphological, structural and elemental characterizations demonstrate the successful decoration of carbon nitride on the composite surface. The electrochemical activity of BVG@C modified glassy carbon electrode reveals excellent redox behaviour towards simultaneous detection of 4-Nitrophenol (4-NP) and 4-Nitroaniline (PNA). The modified electrode shows rapid amperometric current response with high sensitivity of 2.368 μA mM cm^-2 and 1.534 mA mM cm^-2 and low detection limit of 0.012 μmol L^-1and 0.028 μmol L^-1, respectively for 4-NP and PNA. Moreover, the modified electrode was further investigated for hydrogen evolution and oxygen evolution reactions and the electrocatalytic results show admirable activity and good stability for oxygen evolution with very low overpotential of 136 mV in alkaline medium. It is worthwhile to mention that the excellent activity of electrocatalyst can be ascribed to the decoration and electronic interaction of g-C₃N₄ with the BiVO₄/Ag₂CO₃ nanocomposite, increasing its surface area, active sites, charge transfer and decreasing resistance.

Facile preparation of bismuth vanadate-sheet/carbon nitride rod-like interface photocatalyst for efficient degradation of model organic pollutant under direct sunlight irradiation

The photocatalytic performance of a semiconducting catalytic system is strongly influenced by charge-carrier separation rate, charge transport properties, surface area, utilization of light energy, and interface bonding. Herein, a series of bismuth vanadate (BiVO₄) samples were prepared via hydrothermal method by changing the volume ratios of ethelene glycol and ethanol as a solvent mixture for bismuth precursors. Further, the optimized BiVO₄ sheets with hierarchical morphology were used to construct an interface with rod-like g-C₃N₄ materials, which was confirmed by HRSEM and HRTEM. Due to the formation of an effective interface bonding between BiVO₄/g-C₃N₄, the photoinduced charge carrier's recombination rate was suppressed as confirmed by the PL analysis. The prepared BiVO₄/g-C₃N₄ sample were used to assess the photodegradation efficiency of Rhodamine B (RhB) under direct sunlight irradiation and the photocatalysts degraded ~92.8% of RhB within 2 h. The TOC measurements revealed a 66.4% mineralization efficiency for RhB. In addition, the radical trapping experiments demonstrated that superoxide and hydroxyl radicals are the main reactive species for the degradation. Based on the experimental evidences, a plausible charge transfer mechanism has been proposed. The enhanced photocatalytic activity has been mainly attributed to the inhibition of the recombination rate, enhanced charge carrier transfer efficiency, and high rate of production of reactive species.

Visible-Light-Active CuO x -Loaded Mo-BiVO4 Photocatalyst for Inactivation of Harmful Bacteria (Escherichia coli and Staphylococcus aureus) and Degradation of Orange II Dye

In the present study, Mo-BiVO4-loaded and metal oxide (MO: Ag2Ox, CoOx, and CuOx)-loaded Mo-BiVO4 photocatalysts were synthesized using a wet impregnation method and applied for microbial inactivation (Escherichia coli and Staphylococcus aureus) and orange II dye degradation under visible-light (VL) conditions (λ ≥ 420 nm). The amount of MO cocatalysts loaded onto the surface of the Mo-BiVO4 photocatalysts was effectively controlled by varying their weight percentages (i.e., 1-3 wt %). Among the pure Mo-BiVO4, Ag2Ox-, CoOx-, and CuOx-loaded Mo-BiVO4 photocatalysts used in bacterial E. coli and S. aureus inactivation under VL irradiation, the 2 wt % CuOx-loaded Mo-BiVO4 photocatalyst showed the highest degradation efficiency of E. coli (97%) and S. aureus (99%). Additionally, the maximum orange II dye degradation efficiency (80.2%) was achieved over the CuOx (2 wt %)-loaded Mo-BiVO4 photocatalysts after 5 h of radiation. The bacterial inactivation results also suggested that the CuO x -loaded Mo-BiVO4 nanostructure has significantly improved antimicrobial ability as compared to CuOx/BiVO4. The enhancement of the inactivation performance of CuOx-loaded Mo-BiVO4 can be attributed to the synergistic effect of Mo doping and Cu2+ ions in CuOx, which further acted as an electron trap on the surface of Mo-BiVO4 and promoted fast transfer and separation of the photoelectron (e-)/hole (h+) pairs for growth of reactive oxygen species (ROS). Furthermore, during the bacterial inactivation process, the ROS can disrupt the plasma membrane and destroy metabolic pathways, leading to bacterial cell death. Therefore, we provide a novel idea for visible-light-activated photocatalytic antibacterial approach for future disinfection applications.

A Mitocentric View of the Main Bacterial and Parasitic Infectious Diseases in the Pediatric Population

Infectious diseases occur worldwide with great frequency in both adults and children. Both infections and their treatments trigger mitochondrial interactions at multiple levels: (i) incorporation of damaged or mutated proteins to the complexes of the electron transport chain, (ii) mitochondrial genome (depletion, deletions, and point mutations) and mitochondrial dynamics (fusion and fission), (iii) membrane potential, (iv) apoptotic regulation, (v) generation of reactive oxygen species, among others. Such alterations may result in serious adverse clinical events with great impact on children's quality of life, even resulting in death. As such, bacterial agents are frequently associated with loss of mitochondrial membrane potential and cytochrome c release, ultimately leading to mitochondrial apoptosis by activation of caspases-3 and -9. Using Rayyan QCRI software for systematic reviews, we explore the association between mitochondrial alterations and pediatric infections including (i) bacterial: M. tuberculosis, E. cloacae, P. mirabilis, E. coli, S. enterica, S. aureus, S. pneumoniae, N. meningitidis and (ii) parasitic: P. falciparum. We analyze how these pediatric infections and their treatments may lead to mitochondrial deterioration in this especially vulnerable population, with the intention of improving both the understanding of these diseases and their management in clinical practice.

Understanding and Improving Photocatalytic Activity of Pd-Loaded BiVO4 Microspheres: Application to Visible Light-Induced Suzuki-Miyaura Coupling Reaction

The effective utilization of visible light is required for exploiting photocatalytic reactions in indoor and outdoor environments. In this study, Pd-supported BiVO₄ microspheres (Pd-BiVO₄) were prepared for visible light-induced photocatalytic reactions. Under irradiation with a white light-emitting diode, the obtained Pd-BiVO₄ composite exhibited considerably improved catalytic activity for the decomposition of an organic dye compared with other BiVO₄ catalysts. The Pd-BiVO₄ composite was also effective for catalytic organic transformation via the visible light-induced Suzuki-Miyaura coupling reaction. The photogenerated electrons in the conduction band of BiVO₄ flowed to the Pd nanoparticles and amplified cross-coupling reaction. The influence of the crystal structure and grain size of BiVO₄ and the role of the deposited Pd nanoparticles were fully investigated to elucidate the visible light activity of the catalyst. This system highlights the possibility of an indoor light source with low energy density for sustainable organic transformations.

Comprehensive Study of the Growth Mechanism and Photoelectrochemical Activity of a BiVO4/Bi2S3 Nanowire Composite

A BiVO₄/Bi₂S₃ composite comprising Bi₂S₃ nanowires on top of a BiVO₄ film was prepared via hydrothermal reaction. Because additional Bi³⁺ ions were not delivered during the reaction, BiVO₄ served as the Bi³⁺ ion source for the development of Bi₂S₃. A detailed growth mechanism of the nanowire was elucidated by an analysis of the concentration gradient of Bi³⁺ and S^2- ions during the reaction. The in situ growth was followed by the etching of BiVO₄ to Bi³⁺ and VO₄^3- ions and regrowth to Bi₂S₃, which resulted in the rapid evolution of nanowires on the BiVO₄ substrate. The fabricated BiVO₄/Bi₂S₃NW composite exhibited an improved photoelectrochemical activity compared to other Bi₂S₃ samples. The improved efficiency was mainly attributed to both improved charge separation and effective adhesion obtained by the in situ growth.

Deep Eutectic Solvent-Assisted Synthesis of Ternary Heterojunctions for the Oxygen Evolution Reaction and Photocatalysis

Hierarchical nano-/microstructured photocatalysts have drawn attention for enhanced photocatalytic performance. Deep eutectic solvents (DESs) have been used as a green sustainable media to act as both solvent and structure-inducing agent in the synthesis of hierarchical nanomaterials. In this work, the DESs-assisted synthesis of flower-structured BiOCl/BiVO₄ (BOC/BVO) with g-C₃ N₄ (BOC/BVO/g-CN) ternary heterojunctions was achieved by using a simple wet-chemical method, providing good acidic and alkaline oxygen evolution reaction (OER) catalysts. BOC/BVO/g-CN-15 achieved an enhanced photocatalytic activity for OER with an overpotential of 570 mV in 1 m H₂ SO₄ and 220 mV in 1 m KOH electrolyte at a current density of 10 mA cm^-2 with excellent stability and extraordinary durability of the catalyst. The ternary heterojunctions displayed extended lifetimes for photogenerated charges and enhanced the separation efficiency of photogenerated electron-hole pairs, which is helpful to enhance the photocatalytic OER. Furthermore, the photocatalytic performance of the ternary heterojunctions in aqueous solution was demonstrated through photocatalytic dye degradation of methyl orange (MO) as a model pollutant, resulting in 95 % degradation of 20 ppm of MO in 210 min under the irradiation of a 35 W Xe arc lamp. This work not only provides new insight into the design of catalysts by using green solvents but also into the design of highly efficient metal-free OER photocatalysts for applications in acidic and alkaline media.