Insights into the Exfoliation Process of V2O5·nH2O Nanosheet Formation Using Real-Time 51V NMR

Nanomaterials Based Multifunctional Bioactivities of V2O5 and Mesoporous Carbon@V2O5 Composite: Preparation and Characterization

Nanocarriers have attracted considerable interest due to their prospective applications in the delivery of anticancer medications and their distinct bioactivities. Biogenic nanostructures can be effective nanocarriers for delivering drugs as a consequence of sustainable and biodegradable biomass-derived nanostructures that perform specific functions. In this case, a vanadium oxide (V2O5) and mesoporous carbon@V2O5 (C@V) composite was developed as a possible drug delivery system, and its bioactivities, including antioxidant, antibacterial, and anticancer, were investigated. Doxorubicin (DOX), an anticancer drug, was introduced to the nanoparticles, and the loading and release investigation was conducted. Strong interfacial interactions between mesoporous carbon (MC) and V2O5 nanostructures have been found to improve performance in drug loading and release studies and bioactivities. After incubation, the potent anticancer effectiveness was seen based on C@V nanocomposite. This sample was also utilized to research potential biomedical uses as an antioxidant, antibacterial, and anticancer. The most effective antioxidant, the C@V sample (61.2%), exhibited a higher antioxidant activity than the V-2 sample (44.61%). The C@V sample ultimately attained a high DOX loading efficacy of 88%, in comparison to a pure V2O5 sample (V-2) loading efficacy of 80%. Due to the combination of mesoporous carbon and V2O5, which increases specific surface area and surface sites of action as well as the morphology, it proved that the mesoporous carbon@V2O5 composite (C@V) sample demonstrated greater efficacy.

Synthesis of 2D VO2 Nanosheets for the Dual Optical Sensor Method by Colorimetric and Fluorometric Sensing of Catecholamines

For the first time, we report a dual optical sensor method (DOSM) using novel 2D VO2 nanosheets to act as fluorometric and colorimetric sensors to perform quantitative analysis of epinephrine (EP) and dopamine (DA). The wide color spectrum of the 2D vanadium oxidation series and specifically metastable blue 2D VO2 nanosheets were used to develop a DOSM biosensor. DA and EP are the major catecholamines in the human body that play vital roles as neurotransmitters and stress-responsive hormones of the endocrine system, respectively. Accurate and selective detection of these biomolecules can assist in the diagnosis of many neuroendocrine system-related diseases. The newly synthesized 2D VO2 nanosheet sensor showed bluish-green fluorescence as the first-ever fluorescence from 2D VO2 nanosheets. This sensor showed dual-function sensing toward EP by a dominant color change and fluorescence quenching. It is capable of individually detecting and quantifying both EP and DA with high selectivity and sensitivity by using both colorimetry and fluorometry simultaneously, with the detection limits of 1.07 and 5.54 μM for colorimetric analysis, respectively, and 48.07 and 3.98 μM for fluorescence analysis, respectively. The DOSM sensor was directly applied to real urine samples and gained satisfactory recovery above 90% by means of spiked concentrations. This study has opened a new platform using the DOSM and the vanadium oxidation spectrum in a much more effective way for biosensing. The fluorescence capabilities of this metal oxide can be further applied to many sensor applications based on both fluorescence and colorimetric detection.

Vanadium Oxide: Phase Diagrams, Structures, Synthesis, and Applications

Vanadium oxides with multioxidation states and various crystalline structures offer unique electrical, optical, optoelectronic and magnetic properties, which could be manipulated for various applications. For the past 30 years, significant efforts have been made to study the fundamental science and explore the potential for vanadium oxide materials in ion batteries, water splitting, smart windows, supercapacitors, sensors, and so on. This review focuses on the most recent progress in synthesis methods and applications of some thermodynamically stable and metastable vanadium oxides, including but not limited to V₂O₃, V₃O₅, VO₂, V₃O₇, V₂O₅, V₂O₂, V₆O₁₃, and V₄O₉. We begin with a tutorial on the phase diagram of the V-O system. The second part is a detailed review covering the crystal structure, the synthesis protocols, and the applications of each vanadium oxide, especially in batteries, catalysts, smart windows, and supercapacitors. We conclude with a brief perspective on how material and device improvements can address current deficiencies. This comprehensive review could accelerate the development of novel vanadium oxide structures in related applications.

Flexible Freestanding MoO3-x -Carbon Nanotubes-Nanocellulose Paper Electrodes for Charge-Storage Applications

Herein, a one-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO_3-x ) embedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation method involved sonication of the precursors, nanostructured MoO_3-x , CNTs, and CC with weight ratios of 7:2:1, in a water/ethanol mixture, followed by vacuum filtration. The electrodes were straightforward to handle and possessed a thickness of approximately 12 μm and a mass loading of MoO_3-x -CNTs of approximately 0.9 mg cm^-2 . The elemental mapping showed that the nanostructured MoO_3-x was uniformly embedded inside the CNTs-CC matrix. The MoO_3-x -CNTs-CC paper electrodes featured a capacity of 30 C g^-1 , normalized to the mass of MoO_3-x -CNTs, at a current density of 78 A g^-1 (corresponding to a rate of approximately 210 C based on the MoO₃ content, assuming a theoretical capacity of 1339 C g^-1 ), and exhibited a capacity retention of 91 % over 30 000 cycles. This study paves the way for the manufacturing of flexible/freestanding nanostructured MoO_3-x -based electrodes for use in charge-storage devices at high charge/discharge rates.