Hierarchical Hollow Nanospheres Research Articles

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

Artificial thylakoid membrane assisted NiMn2O4@PoPDA hierarchical hollow nanospheres for photo-enzyme integrated catalysis

The selective functionalization of CO2 is of profound significance concerning the global energy and environmental crisis. Herein, we cleverly designed and constructed a photoenzymatic system with a hierarchical hollow structure photo-enzyme integrated catalyst (nickel manganate -poly(o-phenylenediamine), NiMn2O4@PoPDA) by coating NiMn2O4 with artificial thylakoid membrane (PoPDA) to mimic the characteristics of natural thylakoid membranes and combined formate dehydrogenase (FDH) to upgrade CO2 to formic acid. The PoPDA membrane enhances the absorption of light energy and the efficiency of electron transfer, and improves the stability of the enzyme to avoid its deactivation. Most importantly, the favorable electronic coupling and band structure between NiMn2O4 and PoPDA separate holes and electrons to afford a MV•+ regeneration rate of 213.59 ± 4.91 mmol h−1 g−1 and a formic acid yield of 206 µmol. This work creates an efficient strategy using PoPDA as protector for enzyme stabilization to fabricate photobiocatalysts that realize highly efficient photoenzymatic catalysis.

Hierarchical carbon hollow nanospheres coupled with ultra-small molybdenum carbide as sulfiphilic sulfur hosts for lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are an attractive candidate to replace the current state-of-the-art lithium-ion batteries due to their promising theoretical capacity of 1675 mA h g-1 and energy density of 2500 W h kg-1. However, the lithium polysulfide (LiPS) shuttle effect and the slow sulfur redox kinetics seriously decrease the utilization of sulfur and deteriorate battery performance. Here, hierarchical carbon hollow nanospheres containing intimately coupled molybdenum carbide nanocrystals were synthesized as a sulfiphilic sulfur host. The sufficient interior void space accommodates the sulfur and physically confines LiPSs, while the in situ introduced molybdenum carbide nanoparticles can chemically immobilize LiPSs and catalytically accelerate their redox transformations. As a result, the Li-S batteries with this synergistic effect achieve an excellent rate capability of 566 mA h g-1 at 2C and a long cycle stability over 300 cycles at 1C.

Smart l-borneol-loaded hierarchical hollow polymer nanospheres with antipollution and antibacterial capabilities

Porous organic polymers having well-defined morphologies and designable functionalities are potentially suitable materials for environmental remediation, e.g., for the removal of pollutants from water. However, single materials generally do not simultaneously possess high adsorption abilities and antibacterial performance, as well as easy processibility. Herein, we reported a processible porous polymer which composed swellable hollow spherical morphology and branched L-borneol antibacterial agents. These features endure a valuable capability of pollutant absorption for represented pollutants such as, organic dye (methylene blue), organic compound (bisphenol A), and the heavy metal (Cu2+). In addition, the L-borneol groups and 3D crosslinked hierarchical structure result in enhancement of antibacterial performance against Escherichia coli and Staphylococcus aureus. Moreover, we demonstrate the preparation of the polymer as a fine powder could anchored on the membranes, processed into the tablet, adhered with the polyurethane foams, and assembled as the dye absorption device. The rationally designed polymers by this method show notable potential as adsorbents for water purification and sewage treatment.

NiSb@PEO Hollow Nanospheres with Stabilized Structure for Improved Sodium Storage

AbstractAntimony has a high theoretical capacity, is widely used as an anode material for sodium‐ion batteries (SIB). However, the reversible sodiation/desodiation causes the structure collapse of the materials and then a rapid capacity fade. To solve this issue, the rationally designed NiSb@PEO (PEO, polyethylene oxide) hierarchical hollow nanospheres are successfully synthesized via the combination of hydrothermal and galvanic replacement methods. The unique hierarchical hollow nanospheres can alleviate volume expansion and mechanical stress, maintaining structural integrity during cycling. The PEO coating offers a highly conducive network and is conducive to forming stable solid electrolyte interface film on the surface of NiSb nanospheres. In addition, the nanospheres can shorten the transport pathway for the charged species. Benefiting from these structural advantages, NiSb@PEO hollow nanospheres as anodes for SIB display excellent sodium storage properties. At the current density of 100 mA g−1, the initial charge specific capacity of the NiSb@PEO anode is 446 mAh g−1, and the capacity retains 82.5% after 100 cycles. NiSb@PEO can maintain a reversible capacity of 284 mAh g−1 even at a high current density of 1600 mA g−1.

Intimately coupled WS2 nanosheets in hierarchical hollow carbon nanospheres as the high-performance anode material for lithium-ion storage

Intimately coupled WS2 nanosheets in hierarchical hollow carbon nanospheres as the high-performance anode material for lithium-ion storage

Preparation of hierarchical graphdiyne hollow nanospheres as anode for lithium-ion batteries

Carbon-based hollow nanostructures offer promising potential for a variety of energy-related fields, owing to their special structural characteristics and fascinating physicochemical properties. In this paper, graphdiyne hollow nano spheres (GDY-HNSs) were reported to be prepared through a facile solvothermal synthesis technique with copper oxide nanospheres as both template and source of catalyst. The surface morphologies and the shell thickness of the prepared GDY-HNSs can be easily controlled by simply adjusting the amount of the precursor. Besides, the GDY-HNSs exhibit hierarchical nanostructures, large specific surface areas, and appropriate hollow interior, which offer substantial active sites and contact area between electrode and electrolyte while applied as anode, reducing the diffusion paths for both relative ions and electrons. Thus, while applied in lithium-ion batteries, GDY-HNSs show enhanced electrochemical properties, including higher reversible specific capacity, improved rate capacity and cycling performance compared with most of other carbon materials, even in a large mass loading of 2.0 mg cm−2.

Controlled fabrication of orchid-like nitrogen-doped hierarchical porous carbon and hollow carbon nanospheres

Flower-like porous carbon has fascinated significant attention due to its outstanding and exceptional properties. However, controlled synthesis of porous carbon with adjustable morphology, highly active sites and cross-linked pore channels remains still a great challenge. Herein, an inimitable dissolution–reassembly anisotropic growth strategy was firstly demonstrated for the fabrication of idiographic orchid-like hierarchical porous carbon with ultra-thin multilayer carbon sheets, high specific surface area (1063 m2 g−1), large pore volume (0.82 cm3 g−1) and rich nitrogen content (7.6 wt%). Highly reactive phloroglucinol and EDA aggregated magically and SiO2 acted as a pore former. Ingeniously, acetone acted as a “surgical knife,” which cut the composite of SiO2@phloroglucinol–EDA into many tiny units and further anisotropic growth into orchid-like polymers. The width and thickness of the carbon petals can be effectively controlled with the diversification of acetone concentration. Intriguingly, monodisperse hollow carbon nanospheres could be harvested with silicon-deficient system, which may offer new insight into the construction of functionalized carbon materials with hollow architecture. Owing to the unmatched superstructures, orchid-like carbon materials can be employed as an ideal drug carrier and dye adsorbent. Figure Schematic illustration of solid carbon nanosphere, hollow carbon nanosphere and OHPC-25. For the first time, a novel dissolution–reassembly route based on strong hydrogen-bonding interaction was developed to prepare unique orchid-like hierarchical porous carbon, in which phloroglucinol acted as a carbon precursor and EDA both as a base catalyst and as a nitrogen precursor. The critical step to this synthetic approach was the ingeniously employed acetone as a “surgical knife” to cut the composite of SiO2@phloroglucinol–EDA into many tiny units, and these units were reassembled into orchid-like polymers. After adding acetone, the morphology of carbon materials has changed from solid nanospheres to hollow nanospheres. This strategy did not use any template as the cavity, which may offer a new insight into the comprehension of synthesized functionalized carbon materials with hollow architecture.

A self-template strategy to prepare hollow NiMoS4 nanospheres supported on Ni foam as advanced supercapacitor electrodes

Pseudocapacitor has recently emerged as an important electrical energy storage technology that plays a critical role in portable electronic device, hybrid electric vehicle, backup energy system, and so on. In spite of the great advances, preparing ultra-stable pseudocapacitor with excellent electrochemical performance is still very challenging. Herein, we developed a simple but novel self-template method to synthesize hierarchical hollow NiMoS4 nanospheres with ultrathin shell thickness. During the preparation, nickel-molybdenum oxides coated SiO2 precursors were firstly synthesized. After a sulfidation process with Na2S under hydrothermal condition, the precursors were transformed into hierarchical hollow NiMoS4 nanospheres. Simultaneously, the interior SiO2 was well etched by tuning the initial Ni/S molar ratio. In addition, hollow NiMoS4 nanospheres with different shell thickness were also prepared. Remarkably, the obtained NiMoS4 nanospheres show a very high electrochemical activity due to their fascinating structural and compositional features. The electrode prepared from the NiMoS4 nanospheres delivers a high specific capacity of 1094 C g−1 current density of 1 A g−1 with enhanced cycling stability of 97.95% capacitance retention after 10,000 cycles, making them to be potential electrode materials for SCs and other related energy storage devices.

Controlled synthesis of Fe3O4@C@manganese oxides (MnO2, Mn3O4 and MnO) hierarchical hollow nanospheres and their superior lithium storage properties

We develop a facile approach to controlled-synthesize Fe3O4@C@MnOX (MnO2, Mn3O4 and MnO) hierarchical hollow nanospheres by using Fe3O4@C hollow nanospheres as the template. By simply adjusting the calcination temperature and time, three kinds of Fe3O4@C@MnOX (MnO2, Mn3O4 and MnO) hierarchical hollow nanospheres with different phase states of manganese oxides external layer are tailored. In virtue of the synergistic effect of Fe3O4 hollow nanostructures as supporters, the conductive carbon layer and MnOX external layer, the three hollow nanocomposites exhibit excellent lithium storage properties. At 0.1Ag-1, Fe3O4@C@MnO2, Fe3O4@C@Mn3O4 and Fe3O4@C@MnO hierarchical hollow nanospheres still have specific capacities of 708, 833 and 670mAhg−1 after 150 cycles, respectively. Even at 0.5Ag-1, the reversible capacity of the three hollow nanocomposites remains 609, 780 and 523mAhg−1 after 500 cycles, respectively. Interestingly, Fe3O4@C@Mn3O4 hierarchical hollow nanospheres possess more outstanding Li storage properties than Fe3O4@C@MnO2 and Fe3O4@C@MnO hierarchical hollow nanospheres because the former have more stable Mn3O4 external layer during intensive cycles. The rational design of the phase state for Fe3O4@C@MnOX (MnO2, Mn3O4 and MnO) hierarchical hollow nanospheres can provide a novel synthetic strategy for energy storage nanomaterials with optimized performances.

High-performance hierarchical ultrathin sheet-based CoOOH hollow nanospheres with rich oxygen vacancies for the oxygen evolution reaction

We demonstrate the synthesis of hierarchical ultrathin sheet-based CoOOH hollow nanospheres with rich oxygen vacancies for the oxygen evolution reaction.

Cobalt silicate hydroxide nanosheets in hierarchical hollow architecture with maximized cobalt active site for catalytic oxidation

A facile dissolution-regrowth strategy was developed in synthesis of hierarchical hollow nanospheres of cobalt silicate hydroxide (CSH-80) for maximizing cobalt active sites on unit mass basis, which is different from the conventional supported cobalt catalysts. Due to the unique design and elaborative nanoarchitecture, the cobalt active center can be homogeneously dispersed into the structured catalyst, achieving the maximum exposure of the cobalt center for reaction. In activation of peroxymonosulfate (PMS) for degradation of organic contaminants, CSH-80 exhibited outstanding catalytic performance, excellent physicochemical stability and long-term durability, giving 1.9–3.1 folds higher efficiency than that of the conventional supported cobalt catalysts. The turnover frequency of CSH-80 in organic oxidation was 2.0–3.2 folds higher than that of the conventional supported cobalt catalysts. The effects of reaction parameters on contaminant degradation were systematically investigated. The catalytic oxidation mechanism was further elucidated by the quenching tests, electron paramagnetic resonance and photoluminescence studies. The design concept in this study will provide new opportunities for future development of high-performance cobalt-based heterogeneous catalysts in environmental remediation.

A Universal Strategy for Intimately Coupled Carbon Nanosheets/MoM Nanocrystals (M = P, S, C, and O) Hierarchical Hollow Nanospheres for Hydrogen Evolution Catalysis and Sodium-Ion Storage.

Intimately coupled carbon/transition-metal-based hierarchical nanostructures are one of most interesting electrode materials for boosting energy conversion and storage applications owing to the strong synergistic effect between the two components and appealing structural stability. Herein, a universal method is reported for making hierarchical hollow carbon nanospheres (HCSs) with intimately coupled ultrathin carbon nanosheets and Mo-based nanocrystals. The in situ and confined reaction of the synthetic strategy can not only allow the aggregation of the nanocrystals to be impeded, but also endows extremely intimate coupled interaction between the conductive carbon nanosheets and the nanocrystals MoM (M = P, S, C and O). As a proof of concept, the as-prepared MoP/C HCSs exhibit extraordinary hydrogen evolution reaction electrocatalytic activity with small overpotential and robust durability in both acidic and alkaline solutions. In addition, the unique sheet-on-sheet MoS2 /C HCSs as an anode demonstrate high capacity, great rate capabilities, and long-term cycles for sodium-ion batteries (SIBs). The capacity can be maintained at 410 mA h g-1 even after 1000 cycles even at a high current density of 4 A g-1 , one of the best reported values for MoS2 -based electrode materials for SIBs. The present work highlights the importance of designing and fabricating functional strongly coupled hybrid materials for enhancing energy conversion and storage applications.

Hierarchical sodium-rich Prussian blue hollow nanospheres as high-performance cathode for sodium-ion batteries

Recently, Prussian blue and its analogues (PBAs) have attracted tremendous attention as cathode materials for sodium-ion batteries because of their good cycling performance, low cost, and environmental friendliness. However, they still suffer from kinetic problems associated with the solid-state diffusion of sodium ions during charge and discharge processes, which leads to low specific capacity and poor rate performances. In this work, novel sodium iron hexacyanoferrate nanospheres with a hierarchical hollow architecture have been fabricated as cathode material for sodium-ion batteries by a facile template method. Due to the unique hollow sphere morphology, sodium iron hexacyanoferrate nanospheres can provide large numbers of active sites and high diffusion dynamics for sodium ions, thus delivering a high specific capacity (142 mAh/g), a superior rate capability, and an excellent cycling stability. Furthermore, the sodium insertion/extraction mechanism has been studied by in situ X-ray diffraction, which provides further insight into the crystal structure change of the sodium iron hexacyanoferrate nanosphere cathode material during charge and discharge processes.

Rational design of SnO2@C@MnO2 hierarchical hollow hybrid nanospheres for a Li-ion battery anode with enhanced performances

SnO2@C@MnO2 hierarchical hollow hybrid nanospheres have been obtained by coating the MnO2 nanosheet-based hierarchical shell on SnO2@C hollow nanospheres via a redox method. The hierarchical hollow hybrid nanospheres are composed of the SnO2 internal layer with hollow nanostructures, the carbon interlayer and the MnO2 hierarchical nanostructured external layer built from two dimensional nanosheets. SnO2@C@MnO2 nanomaterials exhibit a large initial discharge capacity (1378 mAhg−1), extraordinary cyclic stability (644.5 mAhg−1 after 200 cycles) and rate capability as Li-ion battery anodes. The excellent properties may benefit from the rational design of hierarchical hollow hybrid nanostructures and the synergistic effects between the three layers of SnO2, carbon and MnO2.

Synthesis of hollow NiCo2O4 nanospheres with large specific surface area for asymmetric supercapacitors

Hollow micro-/nanostructured electrode materials with high active surface area are highly desirable for achieving outstanding electrochemical properties. Herein, we report the successful synthesis of hierarchical hollow NiCo2O4 nanospheres with high surface area as electrode materials for supercapacitors. Electrochemical measurements prove that such electrode materials exhibit excellent electrochemical behavior with a specific capacitance reaching 1229 F/g at 1 A/g, remarkable rate performance (∼83.6% retention from 1 to 25 A/g) and good cycling performance (86.3% after 3000 cycles). Furthermore, the asymmetric supercapacitor is fabricated with hollow NiCo2O4 nanospheres electrode and activated carbon (AC) electrode as the positive and negative, respectively. This device exhibits a maximum energy density of 21.5 W h/kg, excellent cycling performance and coulombic efficiency. The results show that hollow NiCo2O4 nanosphere electrode is a promising electrode material for the future application in high performance supercapacitors.

TEOA-mediated formation of hollow core-shell structured CoNi2S4 nanospheres as a high-performance electrode material for supercapacitors

In this study, we report for the first time a cost-effective and general approach for the high-yield synthesis of a hierarchical core-shell and hollow structure of ternary CoNi2S4 in a triethanolamine (TEOA)-assisted hydrothermal system. It is found that a continuous increase in TEOA usages facilitates the formation and transformation of hierarchical CoNi2S4 hollow nanospheres, and the formation mechanism of the unique structure is revealed to be assembly-then-inside-out evacuation and Ostwald ripening mechanism during the sulfidation process. More importantly, when used as faradaic electrode for supercapacitors, the hierarchical hollow CoNi2S4 nanospheres display not only exceptional pseudocapacitve performance with high specific capacitance (2035 Fg−1 at 1 Ag−1) and excellent rate capability (1215 Fg−1 at 20 Ag−1), but also superior cycling stability, with only about 8.7% loss over 3000 cycles at 10 Ag−1. This work can provide some guidance for us in the structural and compositional tuning of mixed binary-metal sulfides toward many desired applications.

Synthesis of Highly Uniform Molybdenum–Glycerate Spheres and Their Conversion into Hierarchical MoS2 Hollow Nanospheres for Lithium‐Ion Batteries

AbstractHighly uniform Mo–glycerate solid spheres are synthesized for the first time through a solvothermal process. The size of these Mo–glycerate spheres can be easily controlled in the range of 400–1000 nm by varying the water content in the mixed solvent. As a precursor, these Mo–glycerate solid spheres can be converted into hierarchical MoS2 hollow nanospheres through a subsequent sulfidation reaction. Owing to the unique ultrathin subunits and hollow interior, the as‐prepared MoS2 hollow nanospheres exhibit appealing performance as the anode material for lithium‐ion batteries. Impressively, these hierarchical structures deliver a high capacity of about 1100 mAh g−1 at 0.5 A g−1 with good rate retention and long cycle life.

Synthesis of Highly Uniform Molybdenum-Glycerate Spheres and Their Conversion into Hierarchical MoS2 Hollow Nanospheres for Lithium-Ion Batteries.

Highly uniform Mo-glycerate solid spheres are synthesized for the first time through a solvothermal process. The size of these Mo-glycerate spheres can be easily controlled in the range of 400-1000 nm by varying the water content in the mixed solvent. As a precursor, these Mo-glycerate solid spheres can be converted into hierarchical MoS2 hollow nanospheres through a subsequent sulfidation reaction. Owing to the unique ultrathin subunits and hollow interior, the as-prepared MoS2 hollow nanospheres exhibit appealing performance as the anode material for lithium-ion batteries. Impressively, these hierarchical structures deliver a high capacity of about 1100 mAh g(-1) at 0.5 A g(-1) with good rate retention and long cycle life.

Hierarchical NiCo2O4 hollow nanospheres as high efficient bi-functional catalysts for oxygen reduction and evolution reactions

High efficient, cost-effective catalysts for both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the key issue of the rechargeable lithium-air batteries. Herein, we report the facile synthesis of hierarchical NiCo2O4 (NCO) hollow nanospheres via a hard template method and following heat treatment. The synthesized hollow NCO consists of ultrathin nanosheets, which could provide larger specific surface area, more active sites and easy access channels for oxygen and electrolyte transport. The electrochemical studies reveal that the NCO hollow owns excellent ORR and OER catalytic activities, characterized with lower onset potential, higher diffusion limiting current density. Moreover, the NCO hollow shows superior stability compared to that of NCO urchin, Pt/C and RuO2 for ORR and OER, respectively. The excellent electrocatalytic activities, long-term stability for both the ORR and OER and the facile synthesis procedure make the NCO hollow a potential promising bi-functional catalyst for the metal-air batteries and fuel cells.