Hollow Nanospheres Research Articles

Constructing a mesoporous carbon nanobowls embedded with ultrafine CoSe2 Nanocrystals for High-Performance potassium ion battery electrode

In the quest for advanced electrode materials for potassium ion batteries (KIBs), an innovative anode featuring ultrafine CoSe2 nanocrystals embedded within mesoporous carbon nanobowls (CoSe2@MCNBs) is presented herein. Diverging from conventional hollow carbon nanospheres, the distinctive bowl structure is crafted to enhance the structural integrity and volumetric energy density of the electrodes. CoSe2@MCNBs synthesized using an iterative drop and dry method followed by selenization exhibit well-preserved morphology with a shell thickness of 20 nm. The successful integration of ultrafine CoSe2 nanocrystals into MCNBs imparts the nanobowls with the benefits of conventional hollow carbon-based composites, including abundant ion storage sites and high electrical conductivity. Simultaneously, the bowl structure boasts a higher packing density than the conventional hollow mesoporous carbon sphere (HMCS) structure, significantly augmenting the volumetric energy density of the fabricated electrode. Capitalizing on these advantages, the CoSe2@MCNB electrode displays exceptional cycling stability, achieving a reversible capacity of 523 mA h g−1 after 500 cycles at 0.5 A/g and an impressive rate capacity of 247 mA h g−1 at 2.0 A/g. This study demonstrates the strong potential of CoSe2@MCNB as an electrode material for the next generation of KIBs.

A sensitive electrochemical biosensor for detection of carbaryl based on hollow covalent-organic frameworks-gold nanoparticles nanospheres

Carbaryl as an important insecticide is always used in agricultures to achieve higher yields. So, rapid detection of carbaryl residues in agricultural products is very necessary due to its potential harm to human beings. Herein, a hollow covalent-organic frameworks (HCOFTFPB-DBD) gold nanoparticles (AuNPs) nanospheres was used to construct a sensitive electrochemical carbaryl biosensor. The surface of electrode modified by HCOFTFPB-DBD-AuNPs nanospheres was negatively charged and repelled the [Fe(CN)6]3-/4-. The acetylcholinesterase (AChE) immobilized on HCOFTFPB-DBD-AuNPs nanospheres catalyzed the hydrolysis of acetylcholine chloride to thiocholine (TCh). The obtained positively charged TCh was adsorbed on the electrode surface by Au-S, which made the electrode surface positively charged to adsorb the negatively charged [Fe(CN)6]3-/4-, showing enhanced oxidation current of [Fe(CN)6]3-/4-. After carbaryl was added, the oxidation current of [Fe(CN)6]3-/4- deceased because ChE activity were inhibited by carbaryl. So, the sensitive detection of carbaryl was achieved at a low potential, which resulted in a high selectivity. The biosensor had a detection limit of 0.38 μM, a linear range of 1.10 μM-40.0 μM, a sensitivity of 0.00863 mA μM−1 and better performance in actual sample.

N-doped hollow carbon nanospheres embedded in N-doped graphene loaded with palladium nanoparticles as an efficient electrocatalyst for formic acid oxidation

Efficient electrocatalysts with a low cost, high activity and good durability play a crucial role in the use of direct formic acid fuel cells. Pd nanoparticles supported on N-doped hollow carbon nanospheres (NHCNs) embedded in an assembly of N-doped graphene (NG) with a three-dimensional (3D) porous structure by a simple and economical method were investigated as direct formic acid fuel cell catalysts. Because of the unique porous configuration of interconnected layers doped with nitrogen atoms, the Pd/NHCN@NG catalyst with Pd nanoparticles has a large catalytic active surface area, superior electrocatalytic activity, a high steady-state current density, and a strong resistance to CO poisoning, far surpassing those of conventional Pd/C, Pd/NG, and Pd/NHCN catalysts for formic acid electrooxidation. When the HCN/GO mass ratio was 1:1, the Pd/NHCN@NG catalyst had an outstanding performance in the catalytic oxidation of formic acid, with an activity 4.21 times that of Pd/C. This work indicates a way to produce superior carbon-based support materials for electrocatalysts, which will be beneficial for the development of fuel cells.

Nanosheets-assembled hollow N-doped carbon nanospheres encapsulated with ultrasmall NiSe nanoparticles for electrocatalytic hydrogen evolution

Developing highly active and stably non-precious metal electrocatalysts for hydrogen production in alkaline conditions is of paramount importance to hydrogen economy. Herein, nanosheet-assembled hollow nitrogen-doped carbon nanospheres confined with ultrasmall NiSe nanoparticles (NiSe@NC) are synthesized by employing a SiO2 template-assisted approach. As expected, the as-prepared NiSe@NC electrocatalyst delivers an overpotential of 169 mV at the current density of 10 mA/cm2 without iR-correction, and sustains at least 80 h for continuous operation, far outperforming the NiSe-p catalyst in 1 M KOH medium toward hydrogen evolution reaction (HER). The appealing HER performance is mainly ascribed to the synergy effect between hollow nitrogen-doped carbon and highly active NiSe nanoparticles, which improves catalytically active sites, expedites electron transfer rate and optimizes the electronic structure of NiSe@NC nanomaterial. More strikingly, this study presents the feasible insights for constructing robust cost-effective electrocatalysts towards efficient HER in harsh alkaline media.

Highly selective QCM sensor based on functionalized hierarchical hollow TiO2 nanospheres for detecting ppb-level 3-hydroxy-2-butanone biomarker at room temperature

Highly selective QCM sensor based on functionalized hierarchical hollow TiO2 nanospheres for detecting ppb-level 3-hydroxy-2-butanone biomarker at room temperature

Yeast‐Controlled Double‐Shelled CaCO3/CaF2 Hollow Nanospheres with Hierarchically Porous for Sustained pH‐Sensitive Drug Release

Comprehensive SummaryHierarchically porous materials (HP materials) are believed one of the most hopeful matrix materials because of their distinctive multimodal pore structures and tremendous application potentials in the field of biomedicine. However, green and facile synthesis of hierarchically porous nanomaterials with beneficial water dispersibility and biocompatibility is still a great challenge. Herein, a novel biomimetic strategy is proposed to prepare the cell‐tailored double‐shelled HPCaCO3/CaF2 hollow nanospheres under the mediation of yeast cells. The biomolecules derived from the secretion of yeast cells are used as conditioning and stabilizing agents to control the biosynthesis of the HPCaCO3/CaF2 materials, which exhibit excellent water dispersibility and favorable biocompatibility. The double‐shelled CaCO3/CaF2 nanospheres hold hierarchically porous structure and have abundant pore channel and large specific surface area, showing high drug‐loading and a prolonged drug sustainable release profile by the pore‐by‐pore diffusion pattern of the hierarchical pores. Otherwise, the HPCaCO3 with pH‐sensitivity could controllably release drug doxorubicin hydrochloride (DOX) at the acidic tumor microenvironment. Both in vitro and in vivo results demonstrate that HPCaCO3/CaF2 has the sustainable pH‐sensitive drug release property, showing an enhanced therapeutic effect. Summarily, this study provides a biomimetic strategy to synthesize the hierarchically porous double‐shelled hollow nanomaterials for applying in sustainable drug delivery system.

Amino acid driven synthesis of gold nanoparticles: A comparative study on their biocompatibility

Gold nanoparticles (GNps) were successfully synthesized via 17 different l-Amino acids (AA-GNps) as reducing agents, in a one-pot reaction. Comparative characterization of AA-GNps revealed variations in their size, morphology, and structure, highly dependent on the nature of the employed amino acid. Aromatic amino acids proved to be fast-reducing agents directing the formation of GNps. Hydroxylic and basic amino acids were the slowest reducing agents for the synthesis of GNps. Aliphatic amino acids produced GNps of similar behavior, except Isoleucine which led to the formation of hollow nanospheres. GNps formulated by aspartic acid and asparagine have comparable properties to citrate-synthesized GNps, which is the golden standard in plasmonic nanoparticles. A new protocol was established for the determination of gold content in GNps’ colloidal solutions via a simple and cost-effective standard curve method employing UV–Vis spectroscopy. Most AA-GNps are colloidally stable, in both aqueous dispersion and simulated body fluid, posing as excellent candidates for in vitro experimentation. Comparative screening for their biocompatibility demonstrated the non-hemolytic and cytocompatible profile of most AA-GNps, via different in vitro assay protocols, performed on blood samples and the healthy cell line of Human Embryonic Kidney cells (HEK-293).

Controllable Synthesis of Hollow Silica Nanospheres

Nano hollow SiO2 refers to a unique form of nanoscale silica material that has an inner cavity structure. This hollow configuration offers several advantages over solid structures, including a larger specific surface area, lower density, and improved permeability. Additionally, hollow silica is chemically inert and thermally stable, making it an excellent candidate for drug delivery applications. Silica's transparency to both light and magnetism ensures that it does not absorb light or disrupt magnetic fields, preserving the inherent optical or magnetic properties of certain composites. In addition, its porosity, biocompatibility, and mechanical stability are adjustable and controllable, making it an ideal and cost-effective material for both industrial and biological uses. This study synthesised a range of hollow spherical silica samples via the sol-gel process. The aim was to investigate the impact of different factors on their sphericity and wall thickness.

Degradable silk fibroin based piezoresistive sensor for wearable biomonitoring

Degradable wearable electronics are attracting increasing attention to weaken or eliminate the negative effect of waste e-wastes and promote the development of medical implants without secondary post-treatment. Although various degradable materials have been explored for wearable electronics, the development of degradable wearable electronics with integrated characteristics of highly sensing performances and low-cost manufacture remains challenging. Herein, we developed a facile, low-cost, and environmentally friendly approach to fabricate a biocompatible and degradable silk fibroin based wearable electronics (SFWE) for on-body monitoring. A combination of rose petal templating and hollow carbon nanospheres endows as-fabricated SFWE with good sensitivity (5.63 kPa−1), a fast response time (147 ms), and stable durability (15,000 cycles). The degradable phenomenon has been observed in the solution of 1 M NaOH, confirming that silk fibroin based wearable electronics possess degradable property. Furthermore, the as-fabricated SFWE have been demonstrated that have abilities to monitor knuckle bending, muscle movement, and facial expression. This work offers an ecologically-benign and cost-effective approach to fabricate high-performance wearable electronics.

Compartmentalization into Outer and Inner Shells of Hollow Nanospheres for Antibiosis Based on Chemistry and Physical Damages.

There is a substantially ascending demand for nonantibiotic strategies to overcome the resistance of bacterial infections. Here, the discovery of a distinctive antibacterial structure is reported. The novel structure of nanoparticle strategy is proposed for appreciable bacteria killing by the smart design of the delayed addition of crosslinkers into the reaction mixture. [2-(methacryloyloxy)ethyl]trimethylammonium chloride solution (MTCl), a water-soluble ionic liquid (IL), has narrow-size material distribution, good whiteness, and high weather resistance. The quaternary ammonium salt is utilized to efficiently permeate cell membranes through electrostatic interaction, accordingly, boasting a beneficiary of antibacterial properties. More importantly, it allows bacteria to attach the nanomaterials easily, especially the double-shelled nanosphere. In light of the introduction of 9-amino(9-deoxy)ep-quinine (QNNH2) on its inner shell, it blocks the nucleic acid and glucose metabolism in bacteria, which is betterment of the antibacterial activity of double-shelled structure nanoparticle compared to other structure of nanomaterials. This physical/chemical/biological triple antibacterial process eliminates the need for traditional antibiotics, and the fabrication strategies and material properties described here provide insights into the design of antibacterial nanomaterials based on chemical and physical effects.

Adjusting photocatalytic hydrogen production of TiO2 hollow nanospheres through nitrogen-induced shallow trapping levels

N-doped titanium dioxide (TiO[Formula: see text] hollow nanospheres with abundant oxygen vacancies were successfully synthesized by coupling urea treatment and annealing in an N2 atmosphere. The pristine TiO2 hollow nanospheres exhibit a shallow donor level for electron trapping, while the urea treatment generates a N 2p acceptor level for hole trapping. After annealing in N2, the sufficient N atoms generate abundant oxygen vacancies for trapping electrons, resulting in further improved charge separation efficiency. The N-doped TiO2 exhibits the highest H2 evolution rate, reaching 2867[Formula: see text][Formula: see text]mol[Formula: see text]g[Formula: see text][Formula: see text]h[Formula: see text], which is six times higher than that of pristine TiO2 hollow nanospheres. The introduction of oxygen vacancies by interstitial N provides a promising way to improve the photocatalysis activity of photocatalysts.

Short-Chain Sulfur Confined into Nitrogen-Doped Hollow Carbon Nanospheres for High-Capacity Potassium Storage.

Carbon-based materials are one of the ideal negative electrode materials for potassium ion batteries. However, the limited active sites and sluggish diffusion ion kinetics still hinder its commercialization process. To address these problems, we design a novel carbon composite anode, by confining highly reactive short-chain sulfur molecules into nitrogen-doped hollow carbon nanospheres (termed SHC-450). The formation process involves the controlled synthesis of hollow polyaniline (PANI) nanospheres as precursors via an Ostwald ripening mechanism and subsequent sulfuration treatment. The high content of constrained short-chain sulfur molecules (20.94 wt%) and considerable N (7.15 wt%) ensure sufficient active sites for K+ storage in SHC-450. Accordingly, the SHC-450 electrode exhibits a high reversible capacity of 472.05 mAh g-1 at 0.1 A g-1 and good rate capability (172 mAh g-1 at 2 A g-1). Thermogravimetric analysis shows that SHC-450 has impressive thermal stability to withstand a high temperature of up to 640 °C. Ex situ spectroscopic characterizations reveal that the short-chain sulfur provides high capacity through reversible formation of K2S. Moreover, its special hollow structure not only provides ample space for highly active short-chain sulfur reactants but also effectively mitigates volume expansion during the sulfur conversion process. This work offers new perspectives on enhanced K+ storage performance from an interesting anode design and the space-limited domain principle.

Hollow carbon nanospheres with optimized nitrogen configuration controlled by heteroatom doping for high-performance potassium-ion storage

As is known, the electrochemical energy storage capability of carbon-based material significantly depends on its intrinsic nitrogen configuration. In this work, the nitrogen configuration in hollow carbon skeleton was controlled by heteroatom phosphorus doping, realized in successfully synthesized N–P co-doping hollow carbon nanospheres (HCNS-NP) samples. When used in K-ion battery, the prepared HCNS-NP electrode retains a discharge capacity of ∼338.8 mA h g−1 at a current density of 100 mA g−1. Furthermore, it achieves a reversible capacity of 180.6 mA h g−1 at a high current density of 1000 mA g−1, even after 1000 cycles. Both experimental and DFT results support that phosphorus doping promote the formation of pyrrole-N within the samples, instead of pyridine-N or graphite-N, which accounts for the enhancement in K-ion conductance and eventually K-ion storage performance. The research opens up a new platform in modifying nitrogen configurations in disordered carbon materials, which should be attractive to the electrochemical, catalysis and material communities.

Ar plasma-engraved rGO/In2O3 hollow nanospheres with rich oxygen vacancies for enhanced triethylamine detection

We successfully constructed a high-performance In2O3 based triethylamine sensor using rGO combined with Ar plasma treatment (Ar-rGO/In2O3). The Ar plasma treatment and rGO doping did not cause significant changes to the crystal structure of In2O3 hollow nanospheres, but increased the content of oxygen vacancies in In2O3, while making the structure of In2O3 hollow nanospheres more porous and thin-walled. The gas sensitivity test results show that this new Ar-rGO/In2O3 based sensor has the advantages of high response (Ra/Rg = 172 to 100 ppm, 4.2 times that of pure In2O3 material), low detection limit (0.5 ppm), fast response speed (1 s), and good stability to triethylamine. It also has excellent selectivity, repeatability, and long-term stability. This work is of great significance for understanding the relationship between response and surface oxygen vacancies of sensitive materials, as well as promoting the development of new triethylamine sensors.

Revealing interfacial charge redistribution of homologous Ru-RuS2 heterostructure toward robust hydrogen oxidation reaction

Precisely tailoring the surface electronic structures of electrocatalysts for optimal hydrogen binding energy and hydroxide binding energy is vital to improve the sluggish kinetics of hydrogen oxidation reaction (HOR). Herein, we employ a partial desulfurization strategy to construct a homologous Ru-RuS2 heterostructure anchored on hollow mesoporous carbon nanospheres (Ru-RuS2@C). The disparate work functions of the heterostructure contribute to the spontaneous formation of a unique built-in electric field, accelerating charge transfer and boosting conductivity of electrocatalyst. Consequently, Ru-RuS2@C exhibits robust HOR electrocatalytic activity, achieving an exchange current density and mass activity as high as 3.56 mA cm−2 and 2.13 mA μgRu-1, respectively, exceeding those of state-of-the-art Pt/C and most contemporary Ru-based HOR electrocatalysts. Surprisingly, Ru-RuS2@C can tolerate 1000 ppm of CO that lacks in Pt/C. Comprehensive analysis reveals that the directional electron transfer across Ru-RuS2 heterointerface induces local charge redistribution in interfacial region, which optimizes and balances the adsorption energies of H and OH species, as well as lowers the energy barrier for water formation, thereby promoting the HOR performance.

Poly(divinylbenzene-maleic acid) Hollow Nanospheres Coordinated with Zirconium: An Effective Catalyst for the Catalytic Transfer Hydrogenation of Furfural to Furfuryl Alcohol

Poly(divinylbenzene-maleic acid) Hollow Nanospheres Coordinated with Zirconium: An Effective Catalyst for the Catalytic Transfer Hydrogenation of Furfural to Furfuryl Alcohol

Atom-Pd catalysts supported by hollow N-doped carbon nanospheres for ultra-efficient nitrogen reduction reaction

Electrochemical N2 reduction reaction (eNRR) presents a promising alternative to the Haber-Bosch process, owing to its mild preparation conditions, absence of costly reagents, and high energy conversion efficiency. However, the process poses significant challenges due to its poor selectivity and low yield. Here, single atom Pd is successfully anchored on N-doped hollow carbon nanospheres via a simple wet impregnation method under relatively mild loading temperature, anhydrous and anaerobic environments. Our experiment demonstrates that SA-Pd/N@C exhibits outstanding catalytic performance in comparison to Pd nanoparticles which is consistent with the results of the DFT calculations, achieving an NH3 yield rate of 132.8 μg·h − 1·mgcat−1 and a corresponding FE of 6 % at -0.2 V versus RHE in HCl electrolyte (pH=1), as well as superior stability with only 5 % decrease after 10 consecutive cycles of electrochemical testing at room temperature, positioning it as one of the most effective catalyst materials reported for eNRR. The exceptional eNRR activity and stability can be attributed to the abundant active sites resulting from the relatively mild loading temperature, as well as electronic effects and structural engineering, which further diminish *H adsorption and efficiently suppress hydrogen evolution reaction. This work will provide a novel approach to enhance the eNRR performance through the effective design of Pd single-atom catalyst

Acidity-activated degradable Mn-engineered silicon nanohybrids coordinated with iprodione for high-efficiency management of Sclerotinia sclerotiorum and nutrient enhancement to crops

Nanocarriers that respond to environmental stimuli are highly desirable in optimizing the bioavailability of pesticides while minimizing side effects. Manganese-engineered nanomaterials hold promising prospects in agriculture as versatile carriers for both intelligent controlled pesticide delivery and crop nutrient enhancement. Here, Mn-engineered hollow silicon nanospheres (Mn-HSNs) with a bubble-like structure were synthesized for encapsulating iprodione (IPR) to obtain IPR-loaded Mn-HSNs (IPR@Mn-HSNs). Due to its high surface area of 261.28 m2/g and surface-enriched active sites, Mn-HSNs demonstrated a commendable loading capacity of 56.4 % for IPR. Results indicated that the -Si-O-Mn- hybrid framework of IPR@Mn-HSNs not only facilitated acidity-triggered IPR release capability but also served as a plentiful source of Mn ion and orthosilicic acid (Si(OH)4) to promote crop growth. The release amount of IPR in an acidic environment generated by Sclerotinia sclerotiorum of oilseed rape was 3.14 times higher than that under neutral conditions. In vitro experiments demonstrated that the antibacterial activity of IPR@Mn-HSNs was about 1.2 times higher than that of commercial IPR suspension concentrate. Appreciably, IPR@Mn-HSNs could be effectively transported to different parts of rapeseed plants through foliar spray, thereby enhancing the effectiveness of pesticide utilization. More importantly, IPR@Mn-HSNs had no discernible impact on the survival of Harmonia axyridis and were relatively safe for HL-7702 and HK-2 cells. Therefore, this work offers valuable insights into the development of an efficient and environmentally friendly pesticide nanoformulation for sustainable and eco-friendly plant protection in agriculture.

A novel fluorescent aptasensor based on H-shaped DNA nanostructure and hollow carbon-doped nitrogen nanospheres for sensitive detection of AFB1

The existence of aflatoxin B1 (AFB1) in food has a high carcinogenic effect on humans and animals. In this study, a fluorescent aptasensor for AFB1 detection was studied by designing a unique H-shaped DNA nanostructure and using novel hollow carbon-doped nitrogen nanospheres (HCNS) as the quenching material. The two DNA strands were hybridized to form the skeleton of the H-shaped DNA nanostructure, and the signal probe (S1-FAM) was paired with complementary bases to form the complete H-shaped DNA nanostructure. When AFB1 was absent, the S1-FAM was replaced by AFB1-Apt and was adsorbed by HCNS to generate a fluorescence resonance energy transfer effect (FRET), causing the signal to turn off. In the presence of AFB1, AFB1 specifically bound to AFB1-Apt to form a complex, which led to the stable formation of the S1-FAM into the H-shaped DNA nanostructure, resulting in the signal turn-on. Under the optimal conditions, an excellent linear relationship (R2 = 0.992) was observed between LgCAFB1 and fluorescent intensity ratio in the range of 0.05–500 ng/mL, and the detection limit was 0.023 ng/mL. The designed aptasensor platform was applied to analyze the spiked AFB1 in peanut, corn flour, wheat flour, wine, and black tea with recoveries ranging from 93.6% to 107.2%.

One-step generation of hollow graphitic carbon nanospheres with suitable oxygenated structures as conductive additives for water-soluble binder in highly stable supercapacitor electrodes

Although the weight ratio of electron conductive additives and the binder to porous carbons in the electrode component of electric double-layer capacitors (EDLC) is minimal, however, without them the electrochemical performances of EDLC would decay quickly. In this work, we present a one-step approach for manufacturing a unique conductive carbon material that shows highly connecting hollow structures as well as approximate oxygenated surface groups to create a synergy effect with aqueous binder and the main component, porous carbon. The as-prepared carbon nanospheres (HCNs) were generated from a typical carbon black-PC20 in air (denoted as PC20HT) at mild temperatures ranging from 400 to 700 °C for 2–4 h at a massive scale of approximate 1 kg h−1. The as-prepared PC20HT displays a high specific surface area of 657 m2 g−1 (the pristine PC20 has 112 m2 g−1) with a pore volume of 0.71 cm3 g−1, and an oxygen content of 14.10 wt%. Interestingly, a premixing of PC20HT and porous carbon is required before making the electrode pastes. The well-premixed carbon materials and a water-soluble binder-polyacrylic acid are composed into highly-stable components as EDLC electrodes in an organic electrolyte. As consequently, the PC20HT-assisted electrodes demonstrate highly stable life cycles (charge-discharge behaviors), with a retention rate 82.13 % over 50,000 cycles at a narrow voltage window of 2.5–2.7 V at 0.5 A g−1 when compared to two conventional conductive carbons, BP2000 (68.45 %) and Super P (67.46 %). Thermal annealing at 900 °C in Ar reduces the oxygen content of PC20HT to 4.25 wt% (referred to as TPC20HT), increasing the retention rate of life cycle to 88.89 % after the same cycles. TPC20HT-assisted EDLC electrodes exhibit a superior energy density of 34.76 Wh kg−1, which is higher than CB-BP2000 and Super P-assisted EDLC electrodes. The transforming of structural morphologies as well as the surface oxygenated and graphitic structures of the as-prepared HCS, PC20HT, and TPC20HT were also described before and after long-term cycling. This simple route for producing conductive carbons is applicable in an aqueous binder system for preparing EDLC electrodes with a cost-effective and environmentally friendly approach.