Hydrothermal synthesis, characterization and enhanced photocatalytic activity and toxicity studies of a rhombohedral Fe2O3nanomaterial

Experimental and computational study of metal oxide nanoparticles for the photocatalytic degradation of organic pollutants: a review

Photocatalysis is a more proficient technique that involves the breakdown or decomposition of different organic contaminants, various dyes, and harmful viruses and fungi using UV or visible light solar spectrum. Metal oxides are considered promising candidate photocatalysts owing to their low cost, efficiency, simple fabricating method, sufficient availability, and environment-friendliness for photocatalytic applications. Among metal oxides, TiO2 is the most studied photocatalyst and is highly applied in wastewater treatment and hydrogen production. However, TiO2 is relatively active only under ultraviolet light due to its wide bandgap, which limits its applicability because the production of ultraviolet is expensive. At present, the discovery of a photocatalyst of suitable bandgap with visible light or modification of the existing photocatalyst is becoming very attractive for photocatalysis technology. However, the major drawbacks of photocatalysts are the high recombination rate of photogenerated electron-hole pairs, the ultraviolet light activity limitations, and low surface coverage. In this review, the most commonly used synthesis method for metal oxide nanoparticles, photocatalytic applications of metal oxides, and applications and toxicity of different dyes are comprehensively highlighted. In addition, the challenges in the photocatalytic applications of metal oxides, strategies to suppress these challenges, and metal oxide studied by density functional theory for photocatalytic applications are described in detail.

Antimicrobial Effectiveness of Innovative Photocatalysts: A Review

Waterborne pathogens represent one of the most widespread environmental concerns. Conventional disinfection methods, including chlorination and UV, pose several operational and environmental problems; namely, formation of potentially hazardous disinfection by-products (DBPs) and high energy consumption. Therefore, there is high demand for effective, low-cost disinfection treatments. Among advanced oxidation processes, the photocatalytic process, a form of green technology, is becoming increasingly attractive. A systematic review was carried out on the synthesis, characterization, toxicity, and antimicrobial performance of innovative engineered photocatalysts. In recent decades, various engineered photocatalysts have been developed to overcome the limits of conventional photocatalysts using different synthesis methods, and these are discussed together with the main parameters influencing the process behaviors. The potential environmental risks of engineered photocatalysts are also addressed, considering the toxicity effects presented in the literature.

Fabrication of spherical porous pAg2O-nWO3/Ag/GNS heterostructure with enhanced photocatalytic activity through plasmonic S-scheme mechanism and its complementing biological interest

The synthesis and characterization of Ag₂OWO₃/Ag/GNS heterostructure with desired modifications has been elucidated in the contemporary study. The fabrication involves a simple hydrothermal method for the configuration of fascinating heterostructures intended to photo-catalytically degrade Eosin Yellow (EY) dye. The toxic dye molecules were converted into non-toxic molecular intermediates, also the elimination of heavy metals from industrial wastewater, being trapped in the pores of heterostructure. The pn junction photocatalyst with plasmonic resonance of Ag for abolition of electron and hole coupling, enhances the photo-response where the catalyst abides S-Scheme mechanism. The work functions of active photocatalysts as calculated for Ag₂O is 6.61eV and WO₃ is 6.04eV. Furthermore, the Ag₂OWO₃/Ag/GNS photocatalysts recovery and reuse in several trials without any noticeable loss of photocatalytic activity, complimented the recyclability of the heterostructure. To ensure the safety of the environment on heterostructure being released, toxicity analysis were carried out. These Ag₂OWO₃/Ag/GNS heterostructures had optimistic result on cytotoxicity assay, and on Musmusculus skin melanoma cells (B16-F10), with anti-microbial/fungal properties. Thereby, the contemporary experiment upholds efficient photocatalysis and ropes multiple errands on biological applications.

Well-orientation strategy for direct binding of antibodies: Development of the immunochromatographic test using the antigen modified Fe2O3 nanoprobes for sensitive detection of aflatoxin B1

One of the major concerns in the application of nanocarriers in biosensing is the impair of the recognition molecules bioactivity loaded on their surfaces due to harsh and laborious cross-linking and random orientation, resulting in unsatisfactory sensitivity. Herein, we proposed a novel immunochromatographic test strip (FNS-ag-DICTS) by taking advantage of the antigen (ag) modified Fe₂O₃ nanostructures (FNSs) as new signal tags and goat anti-mouse IgG labeling on the detection line instead of ag, which was used for sensitive detection of aflatoxin B₁ (AFB₁). The fabricated FNS-ag can orientate the Fab region of monoclonal antibodies (mAbs), waiving the intrinsic limitations of traditional nanomaterials labeled mAbs. Under optimal conditions, FNS-ag-DICTS possessed excellent specificity and a wide detection range, with a visual limit of detection (vLOD) of 0.0125 ng mL^-1. In addition, the biosensor successfully detected AFB₁ in peanut, green bean and corn, with an average recovery rate of 82.8-124.9%.

Effects of size on the photocatalytic properties of high-index faceted pseudocubic and rhombohedral α-Fe2O3 nanocrystals

Size-controlled and high-index faceted α-Fe₂O₃ nanocrystals with pseudocubic and rhombohedral morphologies were synthesized through the hydrothermal treatment of β-FeOOH at different pHs. The size effect on the photocatalytic oxygen evolution efficiency of high-index faceted α-Fe₂O₃ nanocrystals was investigated. Rhombohedral α-Fe₂O₃ (pH 6.0) exhibits an outstanding apparent quantum yield of 9.93% and an oxygen evolution efficiency of 20.3%, which can be attributed to the optimal size and high-indexed {104} planes. This work provides a new idea for the design of high activity water oxidation catalysts, through the size optimization of high-index faceted materials.

Size-controlled and high-index faceted α-Fe₂O₃ nanocrystals with pseudocubic and rhombohedral morphologies were synthesized through the hydrothermal treatment of β-FeOOH at different pHs.