Manufacturing of inorganic nanomaterials: concepts and perspectives

Nanocomposite Marvels: Unveiling Breakthroughs in Photocatalytic Water Splitting for Enhanced Hydrogen Evolution

An overview of the significant innovations in photocatalysts for H2 development, photocatalyst selection criteria, and photocatalytic modifications to improve the photocatalytic activity was examined in this Review, as well as mechanisms and thermodynamics. A variety of semiconductors have been examined in a structured fashion, such as TiO2-, g-C3N4-, graphene-, sulfide-, oxide-, nitride-, oxysulfide-, oxynitrides, and cocatalyst-based photocatalysts. The techniques for enhancing the compatibility of metals and nonmetals is discussed in order to boost photoactivity within visible light irradiation. In particular, further deliberation has been carried out on the development of heterojunctions, such as type I, type II, and type III, along with Z-systems, and S-scheme systems. It is important to thoroughly investigate these issues in the sense of visible light irradiations to enhance the efficacy of photocatalytic action. In fact, another advancement in this area may include hiring mediators including grapheme oxide and metals to establish indirect Z-scheme montages with a correct band adjustment. The potential consideration of reaction chemology, mass transfer, kinetics of reactions, restriction of light diffusion, and the process and selection of suitable light and photoreactor also will optimize sustainable hydrogen output efficiency and selectivity.

Recent Advances in the Development of Lipid-, Metal-, Carbon-, and Polymer-Based Nanomaterials for Antibacterial Applications

Infections caused by multidrug-resistant (MDR) bacteria are becoming a serious threat to public health worldwide. With an ever-reducing pipeline of last-resort drugs further complicating the current dire situation arising due to antibiotic resistance, there has never been a greater urgency to attempt to discover potential new antibiotics. The use of nanotechnology, encompassing a broad range of organic and inorganic nanomaterials, offers promising solutions. Organic nanomaterials, including lipid-, polymer-, and carbon-based nanomaterials, have inherent antibacterial activity or can act as nanocarriers in delivering antibacterial agents. Nanocarriers, owing to the protection and enhanced bioavailability of the encapsulated drugs, have the ability to enable an increased concentration of a drug to be delivered to an infected site and reduce the associated toxicity elsewhere. On the other hand, inorganic metal-based nanomaterials exhibit multivalent antibacterial mechanisms that combat MDR bacteria effectively and reduce the occurrence of bacterial resistance. These nanomaterials have great potential for the prevention and treatment of MDR bacterial infection. Recent advances in the field of nanotechnology are enabling researchers to utilize nanomaterial building blocks in intriguing ways to create multi-functional nanocomposite materials. These nanocomposite materials, formed by lipid-, polymer-, carbon-, and metal-based nanomaterial building blocks, have opened a new avenue for researchers due to the unprecedented physiochemical properties and enhanced antibacterial activities being observed when compared to their mono-constituent parts. This review covers the latest advances of nanotechnologies used in the design and development of nano- and nanocomposite materials to fight MDR bacteria with different purposes. Our aim is to discuss and summarize these recently established nanomaterials and the respective nanocomposites, their current application, and challenges for use in applications treating MDR bacteria. In addition, we discuss the prospects for antimicrobial nanomaterials and look forward to further develop these materials, emphasizing their potential for clinical translation.

Metal Oxide-Related Dendritic Structures: Self-Assembly and Applications for Sensor, Catalysis, Energy Conversion and Beyond

In the past two decades, we have learned a great deal about self-assembly of dendritic metal oxide structures, partially inspired by the nanostructures mimicking the aesthetic hierarchical structures of ferns and corals. The self-assembly process involves either anisotropic polycondensation or molecular recognition mechanisms. The major driving force for research in this field is due to the wide variety of applications in addition to the unique structures and properties of these dendritic nanostructures. Our purpose of this minireview is twofold: (1) to showcase what we have learned so far about how the self-assembly process occurs; and (2) to encourage people to use this type of material for drug delivery, renewable energy conversion and storage, biomaterials, and electronic noses.

The Role of Electrospun Nanomaterials in the Future of Energy and Environment

Electrospinning is one of the most successful and efficient techniques for the fabrication of one-dimensional nanofibrous materials as they have widely been utilized in multiple application fields due to their intrinsic properties like high porosity, large surface area, good connectivity, wettability, and ease of fabrication from various materials. Together with current trends on energy conservation and environment remediation, a number of researchers have focused on the applications of nanofibers and their composites in this field as they have achieved some key results along the way with multiple materials and designs. In this review, recent advances on the application of nanofibers in the areas-including energy conversion, energy storage, and environmental aspects-are summarized with an outlook on their materials and structural designs. Also, this will provide a detailed overview on the future directions of demanding energy and environment fields.

ZnWO4 :Eu3+ phosphor with intense blue LED excitation: photoluminescence and electron density distribution analysis

A high intensity 464 nm excitable ZnWO₄ :Eu³⁺ red-emitting phosphor for warm white lighting applications was prepared using a solid-state reaction method by varying the dopant Eu³⁺ concentration. Crystalline purity and phase identification was confirmed and revealed using powder X-ray diffraction and Rietveld refinement analysis. The surface morphology of Zn_1-x Eu_x WO₄ (x = 0, 0.01, 0.02, 0.03, 0.04 and 0.05) was examined using scanning electron microscopy (SEM) techniques. From SEM analysis, the ZnWO₄ :Eu³⁺ phosphor prepared at 1-3% molar Eu³⁺ concentrations exhibited a small pebble-like morphology with a smooth surface. On increasing the molar concentration of Eu³⁺ to >3%, the pebble stone morphology disappeared and a large, smooth irregular polygon-shaped granular-like morphology was obtained. Of the higher mol% Eu³⁺ , the 4% Eu³⁺ -doped ZnWO₄ showed the best photoluminescence properties with high intensity and sharp excitation at 395 and 464 nm, followed by red emission centred at 615 nm with excellent CIE coordinates (x = 0.58 and y = 0.41) in the core red region. Elemental composition and chemical state analysis were carried out for the 4% Eu³⁺ -doped ZnWO₄ phosphor using X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy studies. Based on all the above analyses, the Eu³⁺ -doped ZnWO₄ phosphor was found to be a very efficient red-emitting phosphor under near-UV light as well as under visible light excitation and could be used for white LED and field emissive displays applications.

Surface Functionalization of Grown-on-Tip ZnO Nanopyramids: From Fabrication to Light-Triggered Applications

We report on a combined chemical vapor deposition (CVD)/radio frequency (RF) sputtering synthetic strategy for the controlled surface modification of ZnO nanostructures by Ti-containing species. Specifically, the proposed approach consists in the CVD of grown-on-tip ZnO nanopyramids, followed by titanium RF sputtering under mild conditions. The results obtained by a thorough characterization demonstrate the successful ZnO surface functionalization with dispersed Ti-containing species in low amounts. This phenomenon, in turn, yields a remarkable enhancement of photoactivated superhydrophilic behavior, self-cleaning ability, and photocatalytic performances in comparison to bare ZnO. The reasons accounting for such an improvement are unravelled by a multitechnique analysis, elucidating the interplay between material chemico-physical properties and the corresponding functional behavior. Overall, the proposed strategy stands as an amenable tool for the mastering of semiconductor-based functional nanoarchitectures through ad hoc engineering of the system surface.

Supramolecular Organization in Confined Nanospaces

Empty spaces are abhorred by nature, which immediately rushes in to fill the void. Humans have learnt pretty well how to make ordered empty nanocontainers, and to get useful products out of them. When such an order is imparted to molecules, new properties may appear, often yielding advanced applications. This review illustrates how the organized void space inherently present in various materials: zeolites, clathrates, mesoporous silica/organosilica, and metal organic frameworks (MOF), for example, can be exploited to create confined, organized, and self-assembled supramolecular structures of low dimensionality. Features of the confining matrices relevant to organization are presented with special focus on molecular-level aspects. Selected examples of confined supramolecular assemblies - from small molecules to quantum dots or luminescent species - are aimed to show the complexity and potential of this approach. Natural confinement (minerals) and hyperconfinement (high pressure) provide further opportunities to understand and master the atomistic-level interactions governing supramolecular organization under nanospace restrictions.

Remarkable Facet Selective Reduction of 4-Nitrophenol by Morphologically Tailored (111) Faceted Cu2O Nanocatalyst

In this work, we have disclosed the facile syntheses of morphologically diverse Cu₂O nanoparticles using our laboratory designed modified hydrothermal reactor employing low-cost copper (II) acetate precursor compounds. The reaction conditions dovetail the effect of ethylene glycol (EG) and glucose to exclusively evolve the morphology tuned Cu₂O nanomaterial at different pHs. The morphology tuning produces octahedron (Oh), dwarf hexapod (DHP), and elongated hexapod (EHP) Cu₂O structures only with the optimized reagent concentrations. Interestingly, all of them were bestowed with a (111) facet, a superlative facet for facile nitroarene reduction. Thus, the morphology reliant catalytic reaction becomes evident. However, when used individually, EG and glucose evolve ill-defined CuO/Cu₂O and Cu₂O structures, respectively. We have observed that a change in pH of the medium at the onset of the reaction is obligatory for the evolution of tailor-made morphologically diverse Cu₂O nanoparticles. However, preformed Cu₂O particles do not suffer further structure/morphology changes under deliberate pH (6.0-9.0) change. With the as-obtained Oh, DHP, and EHP Cu₂O structures, we further delve into the realm of catalysis to understand the splendor of the nanocatalyst, morphology and surface area dependence, facet selective reactivity, and other factors affecting the catalytic efficiency. The remarkable rate of catalysis of 4-nitrophenol (4-NP), evident from the catalyst activity parameter (k _a = 123.6 g^-1 s^-1), to produce 4-aminophenol in the presence of a reducing agent like sodium borohydride (NaBH₄) of the as-prepared catalysts is evidence of the collaborative effects of the effective surface area, surface positive charge, and active (111) facet of the Cu₂O nanocatalyst. We have also studied the effect of other common anions, namely, Cl^-, NO₂ ^-, NO₃ ^-, CO₃ ^2-, and SO₄ ^2- on the reduction process. To obtain a general consensus about facets, we compared (100) and (111) faceted Cu₂O nanocatalysts not only for 4-NP reduction but also for the reduction of toxic chromium Cr(VI) in the presence of formic acid to further emphasize the importance of facet selectivity in catalysis and the versatility of the morphology tuned as-prepared Cu₂O.

Nanobiomaterials' applications in neurodegenerative diseases

The blood-brain barrier is the interface between the blood and brain, impeding the passage of most circulating cells and molecules, protecting the latter from foreign substances, and maintaining central nervous system homeostasis. However, its restrictive nature constitutes an obstacle, preventing therapeutic drugs from entering the brain. Usually, a large systemic dose is required to achieve pharmacological therapeutic levels in the brain, leading to adverse effects in the body. As a consequence, various strategies are being developed to enhance the amount and concentration of therapeutic compounds in the brain. One such tool is nanotechnology, in which nanostructures that are 1-100 nm are designed to deliver drugs to the brain. In this review, we examine many nanotechnology-based approaches to the treatment of neurodegenerative diseases. The review begins with a brief history of nanotechnology, followed by a discussion of its definition, the properties of most reported nanomaterials, their biocompatibility, the mechanisms of cell-material interactions, and the current status of nanotechnology in treating Alzheimer's, Parkinson's diseases, and amyotrophic lateral sclerosis. Of all strategies to deliver drug to the brain that are used in nanotechnology, drug release systems are the most frequently reported.

Seeing is believing: atomic force microscopy imaging for nanomaterial research

Atomic force microscopy can image nanomaterial properties such as the topography, elasticity, adhesion, friction, electrical properties, and magnetism.

Ultra-small Co3O4 nanoparticles–reduced graphene oxide nanocomposite as superior anodes for lithium-ion batteries

A facile solution-based method was reported to prepare ultra-small Co₃O₄ nanoparticles–reduced graphene oxide (Co₃O₄–RGO) nanocomposite as anode material for lithium-ion batteries. This Co₃O₄–RGO nanocomposite showed good electrochemical performance.

Ethylenediamine-mediated synthesis of Mn₃O₄ nano-octahedrons and their performance as electrocatalysts for the oxygen evolution reaction

Mn₃O₄ octahedrons with well-defined facets exhibit enhanced catalytic activity and sensing characteristics, and have attracted considerable attention in recent years. However, current fabrication methods for Mn₃O₄ octahedrons generally produce particles of micron and sub-micron sizes, and impurities such as MnO₂ and Mn₂O₃ are often found. We present the synthesis of Mn₃O₄ nano-octahedrons with a pure Mn₃O₄ phase and size down to 50 nm based on a hydrothermal method using Mn(NO₃)₂ as the manganese source and ethylenediamine (EDA) as the structure-mediating agent. It is found that EDA plays a crucial role in the formation of Mn₃O₄ nano-octahedrons in regulating both the morphology and the crystal structure of the products. The growth process is proposed to follow a "dissolution-recrystallization" and "capping-molecule assisted growth" mechanism. As electrocatalysts towards the oxygen evolution reaction, the 50 nm Mn₃O₄ nano-octahedrons demonstrate a considerably enhanced activity compared to 160 nm Mn₃O₄ octahedrons.

Custom-made morphologies of ZnO nanostructured films templated by a poly(styrene-block-ethylene oxide) diblock copolymer obtained by a sol-gel technique

Zinc oxide (ZnO) nanostructured films are synthesized on silicon substrates to form different morphologies that consist of foamlike structures, wormlike aggregates, circular vesicles, and spherical granules. The synthesis involves a sol-gel mechanism coupled with an amphiphilic diblock copolymer poly(styrene-block-ethylene oxide), P(S-b-EO), which acts as a structure-directing template. The ZnO precursor zinc acetate dihydrate (ZAD) is incorporated into the poly(ethylene oxide) block. Different morphologies are obtained by adjusting the weight fractions of the solvents and ZAD. The sizes of the structure in solution for different sol-gels are probed by means of dynamic light scattering. Thin-film samples with ZnO nanostructures are prepared by spin coating and solution casting followed by a calcination step. On the basis of various selected combinations of weight fractions of the ingredients used, a ternary phase diagram is constructed to show the compositional boundaries of the investigated morphologies. The evolution and formation mechanisms of the morphologies are addressed in brief. The surface morphologies of the ZnO nanostructures are studied with SEM. The inner structures of the samples are probed by means of grazing incidence small-angle X-ray scattering to complement the SEM investigations. XRD measurements confirm the crystallization of the ZnO in the wurtzite phase upon calcination of the nanocomposite film in air. The optical properties of ZnO are analyzed by FTIR and UV/Vis spectroscopy.

Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose

In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu(2)(OH)(2)CO(3) possesses monomodal channel-type pores with largely improved surface area (~43 m(2) g(-1)) and pore volume (0.163 cm(3) g(-1)). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM(-1) cm(-2) and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose as well as the product molecules, which result in the excellent sensitivity and selectivity of sandwich-structured CuO for glucose under non-enzymatic milieu.