Solid Nanospheres Research Articles

Inhalable drug-loaded silk fibroin carriers for pulmonary drug delivery.

The design and development of engineered micro and nano-carriers offering superior therapeutic performance compared to traditional delivery forms, are crucial in pharmaceutical research. Aerosolization and inhalation of carriers with improved solubility/stability of insoluble drugs, has huge potential for targeted drug delivery (DD) in various pulmonary diseases. Indeed, dedicated carriers must meet specific dimensional rules for proper lung delivery. Particles between 2-10 μm in size are normally deposited in the tracheobronchial region, while particles of 0.5-2 μm may be properly deposited in the alveoli. In this work, we report the development of inhalable nanostructured carries made of a 'green' bio-inspired polymer from aqueous solutions, i.e. silk fibroin (SF), efficiently loaded with a hydrophobic drug, i.e. the thyroid hormone levothyroxine (L-T4), a drug for the treatment of idiopathic pulmonary fibrosis. The aim is to optimize a standard method for the synthesis of SF-based nanocarriers with controlled size and shape, where a fine control of their geometrical properties is aimed at efficiently controlling the pulmonary DD. L-T4 loaded SF particles were synthesized through a one-pot co-precipitation method. Optimized systems were determined by varying the chemo-physical parameters during the synthesis. Ethylenediaminetetraacetic acid (EDTA) was used to remove CaCO3 cores. The proposed synthesis routes have led to two SF structures, whose structural heterogeneity and nanostructured morphology have been demonstrated using fluorescence microscopy, DLS, SEM and EDX. Two systems with varying shape and size have been obtained: (i) a flat disk-like SF structure with an irregular surface and an in-plane length of about 1-2 μm; (ii) solid SF nanospheres, obtained using ethylene glycol as additive, showing two size populations (main diameters of 0.5 μm and 1.7 μm). Solid nanospherical systems, in particular, show a tendency to arrange into agglomerates that, when loosely bound into smaller particles, can facilitate the delivery at the alveoli. Both formulations exhibited similar drug loading efficiencies, evaluated by HPLC analysis. However, SF nanospheres showed greater in vitro drug release after 24 hours. The demonstrated control over the characteristics imparted to the proposed DD systems may be critical to select the most suitable size/shape to achieve high rates of delivery to the appropriate lung compartment.

Carbon Nanospheres Loaded with Ir Single Atoms: Enhancing the Activity toward Formic Acid Oxidation by Increasing the Porosity

Theoretically, single‐atom catalysts (SACs) offer 100% atom utilization, making them strong candidates to replace expensive nanoparticles for catalysis. However, the structural supports used to anchor the SACs dramatically reduce the utilization efficiency of atoms (i.e., the percent of atoms actually accessible by reactants) by either encapsulating the SACs completely or creating severe diffusion limitation. Either of which leads to an overall low atom utilization and thus poor electrocatalytic activity similar to that of nanoparticles. In addressing this issue, we systematically investigated how the porous structure of carbon nanospheres affects the activity of Ir‐SACs toward formic acid oxidation (FAO). Specifically, we utilized a kinetically‐controlled growth strategy to produce uniform carbon nanospheres featuring yolk‐shell, mesoporous, and hollow structures with Ir‐SACs loaded throughout the structure. At a high specific surface area of 441 m2 g‐1 and exposed metal content of 1.82 wt.%, the Ir‐SACs based on mesoporous carbon nanospheres showed a remarkable FAO peak current density of 30.6 mA cm‐2, which was 283 and 46 times greater when benchmarked against the catalysts based on solid carbon nanospheres and 20 wt.% Ir/C, respectively.

The role of Ga and Y on binary Al2O3-Y2O3 and Al2O3-Ga2O3 mixed oxides nanoparticles towards potential Ni water-gas shift catalysts

This work focuses on the study of binary Al2O3-Y2O3-x and Al2O3-Ga2O3-x mixed oxides with varying Y2O3 or Ga2O3 nominal loading (x=25, 50) prepared by hydrothermal synthesis assisted by Triton X-100. The mixed oxides were used to prepare Ni-based (5 wt%) catalysts for the Water Gas Shift Reaction. The Al2O3 sample presented urchin-like hollow nanosphere morphology, which evolved to solid nanospheres with Y2O3 or Ga2O3 in the mixed oxides. The physicochemical characterization indicated good integration of the mixed oxides, especially on the low-content additive oxides. The theoretical results confirmed that Ga goes deeper into the alumina matrix than Y, partially explaining the XPS and HRTEM results in which the Ni dispersion was better in the Ni/AlGa-x samples. The FTIR in-situ measurements of the reaction allowed us to propose that the reaction occurs minimally through the carbonyl mechanism at low temperatures (<300 °C) and the formate mechanism at high temperatures (>300 °C).

Size-Dependent Response of Hydrothermally Grown SnO2 for a High-Performance NO2 Sensor and the Impact of Oxygen.

A NO2 sensor with a detection limit down to the ppb level based on pristine SnO2 has been developed through a facile poly(acrylic acid)-mediated hydrothermal method. SnO2 particles of solid microsphere, hollow microsphere, and nanosphere morphologies were synthesized, with respective constitutional crystallite of size ∼2 μm in length and 10-20 nm and ∼7 nm in diameter. All sensors show great selectivity to NO2. The hollow microsphere sensor exhibits the best performance, with medium specific surface area (SSA), followed by the nanosphere sensor with the largest SSA. This is attributed to the superposition of two opposite effects on sensor response with increased SSA: more adsorption sites and fewer electrons to be taken out with overly small crystallite that may reach complete depletion. O2 is found to speed up the response and recovery times but reduce the response because O adsorbates facilitate the adsorption/desorption of NO2 thermodynamically, and the two oxidizing gases compete in harvesting electrons from SnO2. The adverse effect of humidity can be minimized by operating the sensor at 110 °C. The response of the hollow microsphere sensor to 50 ppb of NO2 is 8.8 (Rg/Ra) at room temperature, and it increases to 15.1 at 110 °C. These findings are useful for developing other oxidizing gas semiconductor sensors.

Therapeutic Implementation for Hyperpigmentation and Anti-aging: A Cosmeceutical Approach

Nowadays the most preferred substance to glow skin surface by cosmeceutical products for the aged population and hyperpigmentation cases. These type of skin queries are seen in different environmental conditions including pollution, and radiation. The skin care industries are developing cosmetic products by using natural and synthetic ingredients which is biodegradable and compatible with the skin layer. Cosmetic products currently show drug-like profits because it contain vitamins, antioxidants, essential oils, phytochemical constituents, and enzymes. Cosmo-pharmaceutical products were developing rapidly to avoid skin aging or hypo/hyperpigmentation. The melanocyte or melanin is the main reason for this factor. Selecting natural extracts or resources helps to increase the therapeutic effect and reduces toxicity. The reviewer and researcher found that the term cosmeceutical, skin glowing agent, or hyperpigmentation is widely used in various treatments of melasma, and post-inflammatory hyperpigmentation. The cosmeceutical carefully preclinical and clinical evaluation studies were carried out for safety, and efficacy and no other adverse reactions were shown. Therefore the dermatologist can only provide accurate information to the patient. For the fastest growing area of research and development for a novel formulation of micro-emulsion, nano-emulsion, liposomes, niosomes, solid lipid nanoparticles and nanospheres. These nanocarriers help to incorporate into the formulation and enhance the skin permeation, high stability, and customized release properties with targeting and higher efficacy. The quality of cosmetics and cosmeceuticals is based on evidence of in-vivo and in-vitro efficacy and therapeutic effect

Promoting effect of proanthocyanidin-amorphous calcium phosphate nanoparticles on biomimetic mineralization of demineralized dentin

Biomimetic mineralization is a new strategy for dentin repair emerging in the field of minimally invasive dentistry in recent years. However, the degradation of collagen fibrils and the lack of sustained supply of calcium and phosphorus ions are two main limitations during dentin biomimetic mineralization. Herein, by integrating the dual effects of collagen protection and mineralization induction, we proposed a novel nanoscale platform called proanthocyanidin-amorphous calcium phosphate nanoparticles (PA-ACP/NPs), which were solid nanospheres with uniform size and good biocompatibility, and could continuously release Ca and P ions in neutral or weak acidic microenvironment. PA-ACP/NPs effectively decreased the endogenous collagenase activity of demineralized dentin matrix and protected demineralized dentin collagen from degradation. Compared with the control ACP/NPs, PA-ACP/NPs induced nearly complete intrafibrillar mineralization of collagen fibrils and facilitated remineralization of demineralized dentin. As an additive of dental adhesives for the preliminary exploration of clinical application forms, the adhesive containing 20 wt% PA-ACP/NPs induced biomimetic intrafibrillar mineralization within the bonding interface after one and three months. PA-ACP/NPs nanoscale delivery exhibits excellent effects on stabilizing collagen fibrils and provides a long-term supply of mineral ions for dentin biomimetic mineralization, being a promising strategy for dentin biomimetic repair.

Anisotropic hat-like carbon nanoparticles with tunable inner hollow architectures by growth and dissolution kinetics control

The synthesis of nanoparticles with a hollow and anisotropic structure have attracted considerable interest in synthetic methodology and diverse potential applications, but endowing them with delicate control of the hollow structure and outer anisotropic morphology remains a significant challenge. In this study, anisotropic nanoparticles with hat-like morphology are prepared via a kinetics-controlled growth and dissolution strategy. Starting from forming solid polymer nanospheres with location-specific compositional chemistry distribution based on the distinct reactivity and growth kinetics of two reactants. After etching by acetone, the inhomogeneity nanospheres transformed to hat-like nanoparticles through the kinetics-controlled dissolution of two kinds of precursors. Due to chemical etching and repolymerization reactions occurring within a single nanospheres, an autonomous asymmetrical repolymerization and concave process are observed, which is novel at the nanoscale. Moreover, regulating the amount of ammonia significantly impacts the growth kinetics of precursors, primarily affecting the composition and subsequent dissolution process of solid polymer nanospheres, which play an important role in constructing polymer nanoparticles with varying morphologies and internal structures. The as-synthesized hat-like carbon nanoparticles with an open carbon structure, highly porous shell, and favorable N-doped functionalities demonstrate a potential candidate for lithium-sulfur batteries.

Metal Ion-controlled Growth of Different Metal-Organic Framework Micro/nanostructures for Enhanced Supercapacitor Performance.

We report a metal ion-modulated effective strategy to achieve different metal-organic framework (MOF) micro/nanostructures using different metal precursors like CoCl2 ⋅ 6H2 O, CoCl2 ⋅ 6H2 O and NiCl2 ⋅ 6H2 O, and NiCl2 ⋅ 6H2 O with pyridine-3,5-dicarboxylate (3,5-pdc). The structural characterizations confirm that different morphological structures, hollow microsphere, hierarchical nanoflower, and solid nanosphere are for Co-(3,5-pdc), Co0.19 Ni0.81 -(3,5-pdc), and Ni-(3,5-pdc), respectively. These different MOF micro/nanostructures correlate with the coordination ability of Co and Ni with 3,5-pdc. Benefitting from the synergistic effect of the alloying metal nodes of Co and Ni producing rapid and rich redox reactions and the hierarchical nanoflower with higher surface area enabling excellent ion kinetics, the Co0.19 Ni0.81 -(3,5-pdc) exhibits higher specific capacitance of 515 F g-1 /273 C g-1 at 0.5 A g-1 than that of Ni-(3,5-pdc) (290 F g-1 /153.7 C g-1 ) and Co-(3,5-pdc) (132 F g-1 /67 C g-1 ), good rate capability and cycling stability. Moreover, the asymmetric supercapacitor device (Co0.19 Ni0.81 -(3,5-pdc)//AC) assembled from Co0.19 Ni0.81 -(3,5-pdc) and activated carbon (AC) achieves a maximum energy density of 42.6 Wh kg-1 at a power density of 277.3 W kg-1 .

Enhanced microwave absorption performance of geopolymer composites by incorporating hollow Fe3O4 nanospheres

AbstractHollow Fe3O4 nanospheres (h‐Fe3O4) with tunable sizes were synthesized and proposed as fillers to prepare microwave absorbing geopolymer (GP) composites. We studied the effect of different sizes of h‐Fe3O4 on microwave absorption (MA). The MA performance was enhanced as the size of h‐Fe3O4 in GP decreased. Furthermore, the GP composites containing h‐Fe3O4 achieved better MA capability than their counterparts containing solid Fe3O4 nanospheres (s‐Fe3O4) of the same size. The GP composites with a small size of h‐Fe3O4 exhibited the best minimum reflection loss (RLmin) of −39.3 dB at 14.0 GHz and an effective absorption bandwidth (EAB) of 4.8 GHz at 2.2 mm. The outstanding MA capability, possibly as a result of improved dielectric loss and magnetic loss together with well‐matched impedance, demonstrated that GP composites are competitive construction materials when MA is critical. The radar cross section (RCS) simulation was conducted to assess the MA performance of composite materials in practical environments.

Superior solar water purification achieved by the excellent photothermal conversion and thermal management of porous plasmonic TiN nanoparticles

Solar photothermal steam generation promises decentralized water purification, but the lack of materials that have strong sunlight absorption in wide spectral range, superior thermal management, large specific surface area as well as good water wettability limits the overall solar water purification efficiency. Herein, porous TiN nanospheres are prepared for solar water purification. The monodispersed porous TiN nanospheres are prepared through the wet-chemistry synthesis of TiO2 and followed nitridation. The prepared porous TiN nanospheres have relatively large specific surface area and very good hydrophilicity. In comparison with solid TiN nanospheres, the porous counterparts have stronger light absorption and better thermal management. The optimum solar evaporation film prepared with the porous TiN nanospheres and filter membrane (TiN/FM) exhibits a reflectance smaller than ∼ 19% in the entire solar spectrum. All these merits of the porous TiN nanospheres give rise to a water evaporation rate of 1.68 kg m-2 h−1 and a solar-steam conversion efficiency of 93.4% under AM 1.5 irradiation. Both seawater and polluted water can be purified to potable water with TiN/FM. Our work not only provides a preparation approach for monodispersed porous TiN nanospheres but also demonstrates the great potential of porous plasmonic nanoparticles for the future development of solar water purification.

Recombinant Collagen-Templated Biomineralized Synthesis of Biocompatible pH-Responsive Porous Calcium Carbonate Nanospheres.

The synthesis of calcium carbonate with controlled morphology is crucial for its biomedical applications. In this study, we synthesized well-ordered porous calcium carbonate nanospheres using recombinant collagen as a biomineralization template. Porous collagen-calcium carbonate was created by incubating calcium chloride and sodium carbonate with collagen biotemplates at room temperature. Our results show that the recombinant collagen-calcium carbonate nanomaterials underwent a morphological transition from solid nanospheres to more porous nanospheres and a phase transformation from vaterite to a mixture of calcite and vaterite. This study highlights the crucial role of recombinant collagen in modulating the morphology and crystallinity of calcium carbonate nanoparticles. Importantly, the highly porous recombinant collagen-calcium carbonate hybrid nanospheres demonstrated superior loading efficacy for the model drug cefoperazone. Furthermore, the drug loading and releasing results suggest that hybrid nanospheres have the potential to be robust and biocompatible pH-responsive drug carriers. Our findings suggest that recombinant collagen's unique amino acid content and rodlike structure make it a superior template for biomineralized synthesis. This study provides a promising avenue for the production of novel organic-inorganic nanostructures, with potential applications in biomedical fields such as drug delivery.

DEVELOPMENT AND EVALUATION OF TOPICAL LIPOSOMAL GEL OF LEMON OIL AND ORANGE OIL FOR SYNERGISTIC EFFECT TO ENHANCE SKIN BEAUTY

Background: In the development of cosmeceuticals for skin care, nanotechnology is critical. Essential oils are complex mixtures of numerous derivatives, including terpenoids, aliphatic chemicals, and phenol derived compounds. Due to their numerous qualities such as virucidal, bactericidal, fungicidal, local anaesthetic, anti inflammatory, analgesic, and so on, they have been widely utilized for a long time. Essential oils are chosen over synthetically manufactured medications because they are safer for the skin. To improve the penetration of essential oils via the skin, novel nanosystems such as liposomes, niosomes, nanoemulsions, solid lipid nanoparticles, dendrimers, and nanospheres are used. These nanocarriers allow for controlled release of natural components while also improving their stability. Furthermore, nanotechnology-based skin care products have a pleasing appearance.

Enhancing the electronic and ionic transport of flow-electrode capacitive deionization by hollow mesoporous carbon nanospheres

Flow-electrode capacitive deionization (FCDI) is a promising desalination technology by virtue of its infinite electrosorption capacity and possible continuous operation. However, FCDI still suffers from the limited electronic and ionic transport of its flow-electrode. Herein, we first employed hollow mesoporous carbon nanospheres (HMCNs) as flow-electrode to improve FCDI desalination performance. To understand the dependence of FCDI performance on the structural properties of flow-electrodes, two other samples, activated carbon (AC) and solid mesoporous carbon nanospheres (SMCNs), were selected for comparison. The results showed that HMCNs flow-electrode exhibited excellent rheological behaviors with good dispersibility and increased viscosity. EIS analysis proved that HMCNs flow-electrode had a decreased electrical resistance and enhanced ion diffusion. As expected, HMCNs exhibited improved desalination performance compared with AC and SMCNs. In particular, at 1.2 V with 10 % mass loading, the average salt removal rate, charge efficiency, and energy consumption reached 0.040 mg/cm2∙min, 92.9 %, and 0.035 kWh/mol, respectively. The excellent desalination performance should be attributed to the structural advantage of HMCNs in electronic and ionic transport. Overall, this study provides insights into the dependence of FCDI performance on the structural properties of flow-electrodes, thereby progressing the FCDI technology in relation to electronic/ionic transport.

Curcumin-Based Nanomedicines in the Treatment of Inflammatory and Immunomodulated Diseases: An Evidence-Based Comprehensive Review

Curcumin (CUR) is a polyphenol extracted from the rhizome of Curcuma longa that possesses potent anti-inflammatory and antioxidant potential. Despite CUR's numerous beneficial effects on human health, it has limitations, such as poor absorption. Nano-based drug delivery systems have recently been applied to improve CUR's solubility and bioavailability and potentialize its health effects. This review investigated the effects of different CUR-based nanomedicines on inflammatory and immunomodulated diseases. PUBMED, EMBASE, COCHRANE, and GOOGLE SCHOLAR databases were searched, and the Scale for Assessment of Narrative Review Articles (SANRA) was used for quality assessment and PRISMA guidelines. Overall, 66 studies were included comprising atherosclerosis, rheumatoid arthritis (RA), Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS), Huntington's disease (HD), inflammatory bowel diseases (IBD), psoriasis, liver fibrosis, epilepsy, and COVID-19. The available scientific studies show that there are many known nanoformulations with curcumin. They can be found in nanosuspensions, nanoparticles, nanoemulsions, solid lipid particles, nanocapsules, nanospheres, and liposomes. These formulations can improve CUR bioavailability and can effectively be used as adjuvants in several inflammatory and immune-mediated diseases such as atheroma plaque formation, RA, dementia, AD, PD, MS, IBD, psoriasis, epilepsy, COVID-19, and can be used as potent anti-fibrotic adjuvants in fibrotic liver disease.

Self-templated flower-like NiCoZn-carbonate hydroxide hollow nanospheres for asymmetric supercapacitors with high performance.

With the increasing demand for energy resources, it is crucial to explore electrode materials with high specific capacitance and cycling stability for supercapacitors. Herein, flower-like NiCoZn-carbonate hydroxide (NiCoZn-CH) hollow nanospheres are prepared using self-templated NiCoZn-glycerate solid nanospheres through the Kirkendall effect in a solvothermal reaction. Benefiting from a flower-like morphology, NiCoZn-CH not only provides large contact areas on the electrolyte-electrode and an abundant number of active sites but also shortens the ion transportation pathway. Meanwhile, the hollow structure also improves cycling stability by relieving stresses. Furthermore, Zn2+ can accelerate the ion transfer and improve the electrochemical activity. Therefore, the Ni1Co1Zn0.25-CH electrode shows an attractive specific capacitance of 1585.2 F g-1 at 1 A g-1 and excellent cycling stability. Additionally, the asymmetric supercapacitor Ni1Co1Zn0.25-CH//AC delivers a superior cycling stability of 99.9% after 15 000 cycles at 10 A g-1 and an energy density of 33.7 W h kg-1 at a power density of 400 W kg-1. This work provides a simple and efficient route for the fabrication of various carbonate hydroxides.

Electronic/ionic engineering inspired formation of carbon-encapsulated Cu3PSe4/Cu2Se heterostructured hollow nanosphere for trace level neurochemical monitoring

Exploring metal phosphorus chalcogenides (MPCs) with controllable structure and identified composition for capable of delivering an efficient and reliable sensor on tracking DA in body fluids is crucially challenging and desirable for biomedical research. Currently, we delicately adopt well-defined solid Cu2O nanospheres as initial template and PDA-derived carbon layer as supported skeleton for producing a 3D hollow Cu3PSe4/Cu2Se@C heterostructure nanospheres, which exhibits enhanced electrochemical sensing properties for catalyzing DA, especially its low detection limit and high sensitivity, as compared to its counterparts of Cu3PSe4/Cu2Se and Cu2Se, while it also equipped with powerful selectivity, stability, reproductivity and repeatability. All the excellent catalytic abilities are profited from, on the one hand, the formation of Cu3PSe4 makes the redistribution of the electrons and lower redox potential, on the other hand, the existence of carbon layer maintains a 3D hollow structure and reinforces electric conductivity. More intriguingly, acceptable accuracy evidenced the high reliability and wide feasibility of our Cu3PSe4/Cu2Se@C sensor for complex biological sample. Thus, future studies will focus on the fabrication of more MPXs compounds as functional electrocatalysts in response to diversified health issues.

Sound insulation and mechanical properties of epoxy/hollow silica nanospheres composites

The incorporation of inorganic nanoparticles into a polymer is an effective way to improve its performances. It is common sense that tiny bubbles in epoxy resin will seriously affect the mechanical properties of composites. Based on this common sense, building a small space inside the epoxy resin will obtain some exciting results, because the small space could effectively block the propagation path of sound, and build a small space in the epoxy resin through nano hollow particles, it will be realized sound isolation without sacrificing the mechanical properties of the composites. If this assumption is verified, it will open up a new route to prepare sound insulation materials using thermosetting resin. In this work, two types of nanoparticles of equal size of the hollow silica nanospheres (HSN) and solid silica nanospheres (SN) were synthesized via sol-gel method. Epoxy Resin (EP) matrix composites containing these HSN or SN particles were designed and fabricated as sound insulation materials. The sound transmission loss (STL) properties were investigated using the impedance tubes. The sound insulation results showed that the STL values of neat EP and EP/SN composites with SN content of 2.0 vol% were up to 17.2 dB and 33.9 dB, respectively, while the EP/HSN composites with the same content of HSN was raised to 44.3 dB for the 3 mm thickness samples. Simultaneously, the mechanical properties of the EP/HSN composites were also improved as the certain addition of HSN in epoxy matrix. And the EP/HSN composites hold a potential for outstanding performance soundproofing application.

Controlled Synthesis of Nitrogen-Doped Yolk–Shell Carbon Nanospheres: Tailoring Yolk Size for Lithium–Sulfur Batteries

Nitrogen-doped yolk–shell carbon nanoparticles are one of the most promising functional nanomaterials for various potential applications because of their functionality and adaptability in both the hollow shells and yolks. Yolk–shell nanospheres are known for widely adopted template-based routes, which prove to be expensive and cumbersome and showed inadequate capability to build complex internal structures. Herein, a facile and controllable strategy for fabricating nitrogen-doped yolk–shell carbon nanospheres was proposed through a simple leaching process. The production of the yolk–shell structure is based on the selective dissolution of inhomogeneous solid polymer nanospheres using methanol as leaching agent. The yolk sizes of the nanospheres can be controlled in the range 110–360 nm by simply varying the number of leaching times. In particular, results of the electrochemical properties of the prepared nanospheres with different yolk size suggest that the optimal yolk–shell nanospheres with a yolk size of ∼230 nm delivered the best cycling performance and good capacity retention of 582 mAh g–1 at 1 C after 200 cycles. We believe that the proposed strategy will play a crucial role in energy storage application.

Self-Templating-Oriented Manipulation of Ultrafine Pt3 Cu Alloyed Nanoparticles into Asymmetric Porous Bowl-Shaped Configuration for High-Efficiency Methanol Electrooxidation.

The precise and comprehensive manipulation of the component, size, and geometric nano-architecture of platinum-based electrocatalysts into porous and hollow structure can effectively impart the catalysts with substantially improved electrochemical performance, yet remain formidably challenging. Herein, a straightforward fabrication of porous platinum-copper alloyed nanobowls (abbreviated as Pt3 Cu NBs hereafter) assembled by ultrafine nanoparticles (≈2.9nm) via a one-pot hydrothermal approach with the assistance of a structure-directing agent of N,N'-methylenebisacrylamide (MBAA) is reported. The involvement of MBAA plays a decisive role in the formation of Pt-MBAA complex solid nanospheres, which serve as the self-sacrificial reactive template for the deposition/growth of Pt3 Cu nanoparticles and the eventual formation of the asymmetric open-shelled nanobowls. Benefitting from the 3D sufficient accessibility of exterior/interior surfaces, high atom-utilization efficiency, and PtCu bimetallic alloy synergy, the self-supported Pt3 Cu NBs demonstrate remarkably enhanced activity, better anti-poisoning capability, and reinforced robustness for the methanol oxidation reaction (MOR) as compared with the commercial Pt black benchmark, exhibiting great application promises in practical fuel cell systems. It is envisaged that the innovative self-templated synthetic strategy outlined here may provide a perspective to design a range of porous bowl-shaped high-performance nanocatalysts.

Facile Synthesis of Highly Uniform ZnMn2O4 Hollow Nanospheres with Excellent Lithium Storage Properties

Abstract Hollow nano/micron-structured transition metal oxides (TMOs) hold great potential as electrodes for rechargeable batteries, due to abundant electrochemically active sites, shortened ion diffusion length, and robust architecture. Herein, a facile solvothermal approach combined with post annealing is reported for synthesizing highly uniform ZnMn2O4 hollow nanospheres. The one-pot solvothermal reaction is the key step to form a hollow interior. With solvothermal reaction processing, the precursor solid nanospheres are formed firstly, which gradually evolve into core-shelled structures and finally hollow structures via a self-templated process. Then, the ZnMn2O4 nanospheres with well-inherited hollow interior are obtained by the thermal decomposition of precursors. When evaluated as an electrode, the ZnMn2O4 hollow nanospheres show lithium storage properties superior to solid counterparts, in view of high reversible capacity (735.0 mAh g−1 after 200 cycles at 0.1 A g−1), and ultralong cyclic stability (up to 1000 cycles at 1 A g−1). A dominant pseudocapacitive contribution of 60.0% is identified for the ZnMn2O4 hollow electrode, leading to excellent rate performance. This work provides a new path for preparing TMOs with hierarchically hollow structure.