One-step synthesis of MgO hollow nanospheres with blue emission

Approaches to synthesize MgO nanostructures for diverse applications

Magnesium oxide remained interesting from long time for several important phenomena like; defect induced magnetism, spin electron reflectivity, broad laser emission etc. Moreover, nanostructures of this material exhibited suitability for different kinds of applications ranging from wastewater treatment to spintronics depending upon their shape and size. In this way, researchers had grown nanostructures in the form of nanoparticles, thin films, nanotubes, nanowalls, nanobelts. Though nanoparticles and thin films are well known form of nanostructures and wide variety of synthesis approaches are available, however, limited methodology for other nanostructures are available. In order to grow these nanostructures in an optimized way an understanding of these methods is essential. Thus, this review article depicts an overview of various approaches for design of different kinds of nanostructures.

Development of MgO-sepoilite Nanocomposites against Phytopathogenic Fungi of Rice (Oryzae sativa): A Green Approach

Innovation in agriculture is a vital organ of research for sustainable food supply to the increasing global population. Organic compounds used as fungicidal agents against seed-borne pathogens are bracketed due to their toxic nature and residual effects, which are either already banned or may get banned in the near future. In this study, the surface and electric properties of nontoxic sepiolite have been blended with the antimicrobial properties of metabolizable MgO nanoforms (nMgO) as a greener alternative to prepare their nanocomposites. We compared a sepiolite-MgO (SE-MgO) nanocomposite with MgO nanoparticles in an aqua dispersed form (aqMgO-NPs) for their antifungal evaluation against various phytopathogenic fungi of rice. The SE-MgO nanocomposite was more potent in comparison to aqMgO-NPs with ED₉₀ > 230 and 249 μg/mL, respectively, against the test fungi better than standard fungicides. Ultramicroscopic studies revealed hyphal distortion and spore collapse as the cause of antimycotic activity. The in vitro seed treatment revealed 100% hyphal reduction with SE-MgO at 250 μg/mL of MgO as an active ingredient (a.i.). MgO and sepiolite both have been regarded as safe materials by international agencies; therefore, using their nanocomposites can be an effective, sustainable, nontoxic, eco-friendly, and residue-free strategy for combating fungal menace against phytopathogens.

Millisecond laser ablation of molybdenum target in reactive gas toward MoS2 fullerene-like nanoparticles with thermally stable photoresponse

As a promising material for photoelectrical application, MoS2 has attracted extensive attention on its facile synthesis and unique properties. Herein, we explored a novel strategy of laser ablation to synthesize MoS2 fullerene-like nanoparticles (FL-NPs) with stable photoresponse under high temperature. Specifically, we employed a millisecond pulsed laser to ablate the molybdenum target in dimethyl trisulfide gas, and as a result, the molybdenum nanodroplets were ejected from the target and interacted with the highly reactive ambient gas to produce MoS2 FL-NPs. In contrast, the laser ablation in liquid could only produce core-shell nanoparticles. The crucial factors for controlling final nanostructures were found to be laser intensity, cooling rate, and gas reactivity. Finally, the MoS2 FL-NPs were assembled into a simple photoresponse device which exhibited excellent thermal stability, indicating their great potentialities for high-temperature photoelectrical applications.

Revealing bismuth oxide hollow nanoparticle formation by the Kirkendall effect

We study the formation of bismuth oxide hollow nanoparticles by the Kirkendall effect using liquid cell transmission electron microscopy (TEM). Rich dynamics of bismuth diffusion through the bismuth oxide shell have been captured in situ. The diffusion coefficient of bismuth through bismuth oxide shell is 3-4 orders of magnitude higher than that of bulk. Observation reveals that defects, temperature, sizes of the particles, and so forth can affect the diffusion of reactive species and modify the kinetics of the hollowing process.

Interface-dominated galvanic replacement reactions in the Zn/Cu2+ system

Galvanic replacement (GR) reactions involving active-metal nanoparticles (NPs) as seeds have a number of distinctive features and can produce various noble-metal nanoparticles. The oxide layer on the surfaces of such active-metal seeds may make a remarkable impact on the final products. Taking the Zn/Cu(2+) system as a model, we show that the GR reaction of pure Zn seeds with Cu(2+) ions leads to Cu nanodendrites, while oxide-covered Zn seeds result in ultrafine Cu NPs. We demonstrate here that the oxide layer does not block the GR reaction but slows down its rate. We also show that the growing Cu NPs can eventually detach from their ZnO substrate because of poor adhesion and disperse in the reaction liquid very well. Our studies provide detailed information on mechanisms of the GR reaction involving active-metal seeds, and therefore may be useful for further control of the morphology and properties of products prepared via this approach.