Construction Of Nanostructures Research Articles

Controlled Self-Assembly of Hollow Core-Shell FeMn/CoNi Prussian Blue Analogs with Boosted Electrocatalytic Activity.

Prussian blue analogs (PBAs) are considered as efficient catalysts for energy-related applications due to their porous nanoscale architectures containing finely disseminated active sites. Their catalytic capability can be greatly boosted by the rational design and construction of complex PBA hybrid nanostructures. However, present-day structure engineering inevitably involves additional etchant or procedure. Herein, a facile, yet controllable one-pot self-assembly strategy is introduced to prepare hierarchical core-shell polymetallic PBAs (featuring bimetallic FeMn PBAs cores and CoNi PBAs shells) with hollow nano-cages/solid nano-cube architectures. The detailed characterization of material morphology/composition, assisted with theoretical simulations, reveals the underlying formation mechanism where the key factor is the control of the nucleation rate via the use of chelating agent (citrates) and reaction kinetics. The resulting FeMn@CoNi-H compound is found to accelerate the oxygen evolution reaction activity with a low overpotential (236mV at a current density 10mA cm-2 ) as well as a low Tafel slope (58.4mV dec-1 ). Such an impressive performance is endowed by the rational compositional and structural design with optimized electronic structures as well as an increase in exposed active sites. This work provides a robust, cost-effective pathway that enables chemical and morphological control in creating high-performance catalysts for water electrolysis.

Chemoresistive Gas Sensors for Food Quality Monitoring

The maintenance of food quality has become a crucial assignment to obstruct foodborne diseases in the pandemic era. Various methods have been utilized to monitor the freshness of foods, including gas chromatography-mass spectroscopy (GC-MS). However, most of such methods are not suitable for real-time food quality monitoring. Thus, chemoresistive gas sensors have gained high attention for in-situ monitoring of food quality due to their simple structure, small volume, and low price. Herein, we introduce highly efficient food quality monitoring using chemoresistive gas sensors based on metal oxides, metal sulfides, carbon nanomaterials, polymers, and their composites. We provide diverse strategies to improve the detection of food freshness, such as nanostructure construction and heterostructure formation.

Electrochemical Preparation of Nanocatalysts and Their Application in Electrocatalysis.

In order to solve the basic problem of high-temperature sintering of molybdenum carbide restricting the efficient construction of molybdenum carbide nanostructures and the full play of hydrogen evolution performance, this article studies the preparation of nano molybdenum carbide/boron nitrogen codoped two-dimensional carbon composite structure catalysts and the electrochemical hydrogen evolution reaction performance. Based on the self-assembly process of gelatin molecules on the surface of a two-dimensional layered boric acid crystal template, a new strategy for constructing a high-performance electrochemical hydrogen evolution reaction catalyst based on molybdenum carbide/boron nitrogen codoped two-dimensional nanocarbon composite structure (η-MoC@ BN-CSs) was established. The experimental results show that the overpotential of hydrogen evolution reaction based on molybdenum carbide/boron nitrogen codoped two-dimensional nanocarbon composite structure catalyst is 159 mV, which is slightly higher than 67 mV of commercial Pt/C catalyst, but lower than the reported literature value in the list. The Tafel slope is 68 mV·dec−1, which is slightly higher than that of the commercial Pt/C catalyst (40 mV·dec−1) and the reference value (58 mV·dec−1), but lower than those of other reported literature values in the list, indicating that the molybdenum carbide/boron nitrogen codoped two-dimensional carbon nanocomposites have excellent catalytic performance under alkaline conditions. Conclusion. This kind of two-dimensional nanocomposite structure shows platinum-like catalytic activity when used as an electrochemical hydrogen evolution catalyst in alkaline electrolyte. It has better reaction kinetics and better stability.

Fabrication of copper-cobalt heterostructures confined inside N-doped carbon nanocages for long-lasting Zn-air batteries

Delicate construction of sophisticated bimetallic nanostructures provides a favorable way to boost the efficiency of bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), which is critical to the fabrication of rechargeable Zn-air batteries. Herein, hetero-structured Cu/Co93Cu7 nanoparticles confined inside N-doped carbon nanocages (denoted as Cu/Co93Cu7@NC NCs) are fabricated through a facile “MOF-in situ-reduction and in situ-growth-MOF” strategy. Benefiting from the unique hollow architecture and superior intrinsic activity of the optimized interfaces, the as-prepared catalyst displays an appealing electrocatalytic performance including a positive half-wave potential (E1/2) of 0.88 V for ORR and a low OER overpotential of 262 mV at 10 mA cm−2. Theoretical calculations further disclose the key role of the rationally designed Co/Cu/N-doped carbon heterostructures, which significantly reduces the energy barrier for *OOH formation and eventually promotes the ORR. Rechargeable Zn-air batteries assembled with the Cu/Co93Cu7@NC NCs exhibit a large specific capacity of 884.9 mAh gZn−1 and a maximum power density of 225.9 mW cm−2. Moreover, the assembled batteries are stable for 1000 h during the long-term charge and discharge cycling, demonstrating the great promise for practical applications.

Construction of CoMo2 S4 Nanorods/Nanosheets Electrodes with Enhanced Electrochemical Properties for Asymmetric Pseudocapacitors.

The construction of hierarchical nanostructures and the synergistic effect of bimetal compounds provide effective strategies to address the low energy density of supercapacitors. Herein, CoMo2 S4 (CMS) nanosheets anchored on homogeneous nanorods vertically distributed on nickel foam (NF) were fabricated using a two-step hydrothermal method. The hierarchical homostructure CMS materials heavily depend on the vulcanization parameter of the second step synthesis. As an electrode of supercapacitors, CoMo2 S4 exhibits a large specific capacity of 1992.85 F g-1 at 2 mA cm-2 , and specific capacity retention of 106 % through 8000 cycles when sulfurization condition was at 120 °C for 6 h (CMS/NF-120). Such excellent performances benefit from hierarchical homostructure, which can provide a large reaction surface area, fast ion/electron diffusion channels and rich active sites. Furthermore, the asymmetric pseudocapacitors device constructed with CMS/NF-120 and active carbon exhibits a maximum energy density of 39.8 Wh kg-1 , and good long-term stability (80.1 % capacitance retention after 10,000 cycles).

Recent Advances in Nanostructured Inorganic Hole-Transporting Materials for Perovskite Solar Cells.

Organic-inorganic halide perovskite solar cells (PSCs) have received particular attention in the last decade because of the high-power conversion efficiencies (PCEs), facile fabrication route and low cost. However, one of the most crucial obstacles to hindering the commercialization of PSCs is the instability issue, which is mainly caused by the inferior quality of the perovskite films and the poor tolerance of organic hole-transporting layer (HTL) against heat and moisture. Inorganic HTL materials are regarded as promising alternatives to replace organic counterparts for stable PSCs due to the high chemical stability, wide band gap, high light transmittance and low cost. In particular, nanostructure construction is reported to be an effective strategy to boost the hole transfer capability of inorganic HTLs and then enhance the PCEs of PSCs. Herein, the recent advances in the design and fabrication of nanostructured inorganic materials as HTLs for PSCs are reviewed by highlighting the superiority of nanostructured inorganic HTLs over organic counterparts in terms of moisture and heat tolerance, hole transfer capability and light transmittance. Furthermore, several strategies to boost the performance of inorganic HTLs are proposed, including fabrication route design, functional/selectively doping, morphology control, nanocomposite construction, etc. Finally, the challenges and future research directions about nanostructured inorganic HTL-based PSCs are provided and discussed. This review presents helpful guidelines for the design and fabrication of high-efficiency and durable inorganic HTL-based PSCs.

Metal organic framework-derived Zr/Cu bimetallic photocatalyst for the degradation of tetracycline and organic dyes

The exploitation of tetracycline antibiotics (TCs) has caused significant hazards to both the humans as well as the environment. As a result, developing efficient strategies to eliminate these contaminants is both important and practicable. Photocatalytic degradation appears to be one of the most potential techniques for extracting antibiotics. Semiconductors seem to be the most extensively used photocatalysts even though their performance is still hampered by light absorption limitations and poor charge separation. MOFs are worthy choices for the construction of hierarchical nanostructures with semiconductors to address the foregoing concerns because of their extraordinary features including better surface area and extensive active sites. Zr/Cu-MOF was synthesised by precipitation refluxing method and its efficacy as a photocatalyst for the degradation of TC antibiotics and poisonous dyes such as rhodamine B and methylene blue was examined in this study. The Zr/Cu-MOF displayed excellent efficacy for degradation of tetracycline (93 % in 80 min), Rhodamine B (96 % in 70 min) and methylene blue (96 % in 50 min) with rate constant of 0.0308, 0.052 and 0.068 min−1. The contribution of reactive species in antibiotics and dye degradation was confirmed by radical scavenging investigations which showed that.OH radical has a significant role in photocatalytic decomposition. In addition, tests using liquid chromatography-mass spectrometry (LC-MS) were carried out in order to predict a probable mechanism for TC degradation.

Multi-Domains in a Single Lattice Formed by DNA Self-Assembly.

Using sequence programmability and the characteristics of self-assembly, DNA has been utilized in the construction of various nanostructures and the placement of specific patterns on lattices. Even though many complex structures and patterns formed by DNA assembly have been reported, the fabrication of multi-domain patterns in a single lattice has rarely been discussed. Multi-domains possessing specifically designed patterns in a single lattice provide the possibility to generate multiple patterns that enhance the pattern density in a given single lattice. Here, we introduce boundaries to construct double- and quadruple-domains with specific patterns in a single lattice and verify them with atomic force microscopy. ON, OFF, and ST (stripe) patterns on a lattice are made of DNA tiles with hairpins (ON), without hairpins (OFF), and alternating DNA tiles without and with hairpins (formed as a stripe, ST). For double- and quadruple-domain lattices, linear and cross boundaries were designed to fabricate two (e.g., ON and OFF, ON and ST, and OFF and ST) and four (OFF, ST, OFF, and ON) different types of patterns in single lattices, respectively. In double-domain lattices, each linear boundary is placed between two different domains. Similarly, four linear boundaries connected with a seed tile (i.e., a cross boundary) can separate four domains in a single lattice in quadruple-domain lattices. Due to the presence of boundaries, the pattern growth directions are different in each domain. The experimentally obtained multi-domain patterns agree well with our design. Lastly, we propose the possibility of the construction of a hexadomain lattice through the mapping from hexagonal to square grids converted by using an axial coordinate system. By proposing a hexadomain lattice design, we anticipate the possibility to extend to higher numbers of multi-domains in a single lattice, thereby further increasing the information density in a given lattice.

Box-shaped ribozyme octamer formed by face-to-face dimerization of a pair of square-shaped ribozyme tetramers

Naturally occurring ribozymes with defined three-dimensional (3D) structures serve as promising platforms for the design and construction of artificial RNA nanostructures. We constructed a hexameric ribozyme nanostructure by face-to-face dimerization of a pair of triangular ribozyme trimers, unit RNAs of which were derived from the Tetrahymena group I ribozyme. In this study, we have expanded the dimerization strategy to a square-shaped ribozyme tetramer by introducing four pillar units. The resulting box-shaped nanostructures, which contained eight ribozyme units, can be assembled from either four or two components of their unit RNAs.

Metal-Based Nanostructured Therapeutic Strategies for Glioblastoma Treatment-An Update.

Glioblastoma (GBM) is the most commonly diagnosed and most lethal primary malignant brain tumor in adults. Standard treatments are ineffective, and despite promising results obtained in early phases of experimental clinical trials, the prognosis of GBM remains unfavorable. Therefore, there is need for exploration and development of innovative methods that aim to establish new therapies or increase the effectiveness of existing therapies. One of the most exciting new strategies enabling combinatory treatment is the usage of nanocarriers loaded with chemotherapeutics and/or other anticancer compounds. Nanocarriers exhibit unique properties in antitumor therapy, as they allow highly efficient drug transport into cells and sustained intracellular accumulation of the delivered cargo. They can be infused into and are retained by GBM tumors, and potentially can bypass the blood–brain barrier. One of the most promising and extensively studied groups of nanostructured therapeutics are metal-based nanoparticles. These theranostic nanocarriers demonstrate relatively low toxicity, thus they might be applied for both diagnosis and therapy. In this article, we provide an update on metal-based nanostructured constructs in the treatment of GBM. We focus on the interaction of metal nanoparticles with various forms of electromagnetic radiation for use in photothermal, photodynamic, magnetic hyperthermia and ionizing radiation sensitization applications.

A multi-storey DNA nanostructure containing doxorubicin and AS1411 aptamer for targeting breast cancer cells

Herein, we presented a novel DOX-loaded multi-storey DNA nanostructure, including AS1411 aptamer as a targeting agent for treatment of target cells (MCF-7 and 4T1). Gel retardation test and fluorometric analysis were used to examine the construction of DNA nanostructure and loading of DOX in the complex. At pH 5.5 and 7.4, the release patterns of DOX from the prepared formulation were studied. Cell viability test was conducted to analyse the cell cytotoxicity ability of the DOX loaded multi-storey DNA nanostructure compared to free DOX in 4T1, MCF-7 (target) and CHO cells (non-target). Flow cytometry analysis was used to examine the DOX-loaded DNA nanostructure internalisation. Finally, the developed DOX-loaded multi-storey DNA nanostructure was tested in vivo to see if it could prevent tumour growth. The drug was released from the nanocomplex in a pH-related process (higher release in acidic pH compared to neutral pH). According to MTT assay, DOX-loaded DNA nanostructure damaged nucleolin positive cells while not significantly affecting nucleolin negative cells. The formulation was efficaciously internalised into target cells (4T1 and MCF-7), but not into non-target ones. Moreover, DOX-loaded DNA nanostructure can restrict tumour growth, increase survival rate, and accumulate significantly more in the tumour site than free DOX.

Design and synthesis of cellulose nanofiber-derived CoO/Co/C two-dimensional nanosheet toward enhanced and stable lithium storage

Nano-sized two-dimensional carbonaceous materials have been widely used as the matrix for alloying-type and conversion-type anode materials for Li-ion batteries (LIBs) to improve structural stability and rate performance. However, relevant synthesis usually requires rigorous conditions and chronic reaction processes. Herein, we have designed a simple solvothermal reaction and heat treatment to prepare a novel CoO/Co/C two-dimensional nanosheet (CoO/Co/C 2DNS) by adopting cellulose nanofibers (CNFs) as the precursor. The unique characteristics of CNFs facilitate the uniform distribution of active materials on the surface and the construction of two-dimensional nanostructure via self-assembly. It is worth noting that CoO/Co/C 2DNS exhibits a striking synergistic effect since the porous 2D carbon framework offers additional pseudo-capacitance and enhances the electronic conductivity, while the ultrafine active materials encapsulated inside shorten the Li-ions diffusion pathways and relieve the volume change. Benefit from the unique structure, the composite anode delivered outstanding rate performance (∼500 mAh g−1 at 10 A g−1) and superior long-range cycling performance up to 800 cycles even at 2 A g−1. This work provides a new strategy for the synthesis of nano-sized 2D composite, offering a promising route to construct high performance conversion-type anodes for next-generation LIBs.

Dimensional‐Transformation of Ternary‐Alloy through the Manipulation of Reduction Kinetics

AbstractAlthough significant progress is achieved for the synthesis of noble metal‐based nanocrystals (NCs), the construction of nanostructures with switchable dimensionality is not reported yet. Herein, a facile and general approach for the synthesis of multimetallic (PtCuPb and PtAgPb) NCs with dimensional‐switching properties by manipulating the reduction rate involved in the growth of 2D nanosheets (2D‐NS) and 1D nanowires (1D‐NW) is presented. At a slow reduction rate, PtCuPb and PtAgPb NCs grow to form 2D‐NS, in contrast, at a fast reduction rate, dimensionality alteration occurs to form 1D‐NW. This 2D‐NS to 1D‐NW transition generates compressive surface strain in PtCuPb‐NW with unique intermetallic core, active surface composition and exposes facet to boost oxygen reduction reaction (ORR). In PtCuPb‐NW, compressive strain shifting the d‐band electronic structure of platinum and weakening chemisorption of oxygenated species are shown. In detail, PtCuPb‐NW/C exhibits superior specific and mass activities (4.91 mA cm−2 and 2.65 A mgPt−1) for ORR that are ≈19 and ≈15 times higher than the commercial Pt/C. The observations made and chemical principles unveiled in this effort indicate that a general approach exists for dimensional‐switching and show a new class of Pt‐based electrocatalysts with enhanced performance for fuel cells.

Metal ion-regulated assembly of designed modular protein cages.

Coiled-coil (CC) dimers are versatile, customizable building modules for the design of diverse protein architectures unknown in nature. Incorporation of dynamic self-assembly, regulated by a selected chemical signal, represents an important challenge in the construction of functional polypeptide nanostructures. Here, we engineered metal binding sites to render an orthogonal set of CC heterodimers Zn(II)-responsive as a generally applicable principle. The designed peptides assemble into CC heterodimers only in the presence of Zn(II) ions, reversibly dissociate by metal ion sequestration, and additionally act as pH switches, with low pH triggering disassembly. The developed Zn(II)-responsive CC set is used to construct programmable folding of CC-based nanostructures, from protein triangles to a two-chain bipyramidal protein cage that closes and opens depending on the metal ion. This demonstrates that dynamic self-assembly can be designed into CC-based protein cages by incorporation of metal ion–responsive CC building modules that act as conformational switches and that could also be used in other contexts.

Utilizing RNA origami scaffolds in Saccharomyces cerevisiae for dCas9-mediated transcriptional control.

Designer RNA scaffolds constitute a promising tool for synthetic biology, as they can be genetically expressed to perform specific functions in vivo such as scaffolding enzymatic cascades and regulating gene expression through CRISPR-dCas9 applications. RNA origami is a recently developed RNA design approach that allows construction of large RNA nanostructures that can position aptamer motifs to spatially organize other molecules, including proteins. However, it is still not fully understood how positioning multiple aptamers on a scaffold and the orientation of a scaffold affects functional properties. Here, we investigate fusions of single-guide RNAs and RNA origami scaffolds (termed sgRNAO) capable of recruiting activating domains for control of gene expression in yeast. Using MS2 and PP7 as orthogonal protein-binding aptamers, we observe a gradual increase in transcriptional activation for up to four aptamers. We demonstrate that different aptamer positions on a scaffold and scaffold orientation affect transcriptional activation. Finally, sgRNAOs are used to regulate expression of enzymes of the violacein biosynthesis pathway to control metabolic flux. The integration of RNA origami nanostructures at promoter sites achieved here, can in the future be expanded by the addition of functional motifs such as riboswitches, ribozymes and sensor elements to allow for complex gene regulation.

A simple and universal strategy for construction and application of silica-based flame-retardant nanostructure

Inorganic-organic nanocomposites present excellent comprehensive performance due to the combination of the advantages of inorganic, organic, and nanotechnology. However, the preparation methods are usually complex and inefficient, especially not universal. Here, a simple and universal strategy was designed for preparing silica-based nanocomposite flame retardants . Mesoporous silica (m-SiO 2 ) was used to load ethylenediamine tetra(methylene phosphonic acid) (EDTMPA). Above the melting point of EDTMPA, molten EDTMPA enters into the mesoporous channels of m-SiO 2 by means of capillary force . After cooling, EDTMPA is fixed in the mesoporous cavity to form a flame retardant nanostructure containing silicon, phosphorus, and nitrogen (SiP). The whole process of mesoporous silica-loaded organic flame retardant is simple and green. Adding 3 phr SiP2 into epoxy (EP) resin can reduce the peak heat release rate , total smoke production, and peak CO production by 44.3%, 30.4%, and 45.5%, respectively. Besides, it shows good mechanical properties compared with the EP composites with physically blended m-SiO 2 and EDTMPA. These excellent performances are attributed to the combined effect of EDTMPA and m-SiO 2 as well as the nanoscale effect . This strategy provides a simple, efficient, and general method to prepare nanocomposites by loading molten organic compounds into m-SiO 2 . • A new universal strategy for preparing silica-based nanocomposite is developed. • Molten organic flame retardant was loaded into the channels of mesoporous silica. • A novel flame retardant containing silica, phosphorus, and nitrogen was obtained. • The flame retardant has better comprehensive properties than comparative samples. • The process of mesoporous silica-loaded organic flame retardant is simple and green.

Tailoring of hierarchical MnMoO4/C nanocauliflowers for high-performance lithium/sodium ion half/full batteries

• Hierarchical MnMoO 4 /C nanocauliflowers are successfully fabricated. • Structure engineering and surface modification are simultaneously achieved. • MnMoO 4 /C nanocauliflowers exhibit excellent lithium/sodium storage performance. • MnMoO 4 /C nanocauliflowers can be successfully applied to Li/Na ion full cells. Metal molybdates inherit the characteristics of polyoxometalates (POMs) and have been widely used in the fields of catalysis, photoluminescence and energy storage. However, well construction of hierarchical molybdate nanostructures towards superior performance has still retained a critical challenge. Herein, hierarchical manganese molybdate (MnMoO 4 ) nanocauliflowers are tailored from aggregated microrods utilizing dopamine as a scissor at room temperature. Meanwhile, a uniform and robust carbon coating layer can be introduced after a simple calcination. The fabricated MnMoO 4 /C nanocauliflowers exhibit excellent electrochemical properties as anodes for both lithium/sodium ion half/full batteries. The boosted discharge specific capacities and rate capabilities of MnMoO 4 /C (994 mAh g −1 at 0.1 A g −1 and 487 mAh g −1 at 2.0 A g −1 for lithium ion battery and 296 mAh g −1 at 0.1 A g −1 and 148 mAh g −1 at 2.0 A g −1 for sodium ion battery) are better than those of bare MnMoO 4 . Notably, the stable and sustainable cyclic property with 1500 times for lithium ion battery and 5000 times for sodium ion battery without obvious capacity fading is much superior to the state-of-art results of many other reported molybdates. This simple yet effective strategy demonstrates the feasibility of simultaneous structure engineering and surface modification of molybdates.

Construction of anisotropic nanostructures by self-assembly of aggregation-induced emission driven from tris-branched [2]rotaxane based molecular zipper

The rotaxane-based molecular machines can lead to the appearance of unconventional operations and properties thus, by integrating with aggregation-induced emission (AIE) features to control the construction of polymorphism through supramolecular self-assembly can reach an amazing level of intelligent materials. We rationally described a tris-branched TPE [2]rotaxane RZ3+ of a molecule shuttle, composed of t-butylcalix [4]arene macrocycle, a single axle incorporating ammonium motif, and a bifurcated double strand each containing 1,2,3-triazolium (Tz) cationic unit that terminated with a tetraphenylethene (TPE) stopper. The “concealed” and “exposed” state of the ammonium moiety by a [2]rotaxane RZ3+ is displayed to correspond to opening and closing of the double strand, respectively, which resembles a zipper-like functioning. Distinctive anisotropic nanostructures including nanofibers, nanorods, coarsely truncated shapes, pseudocubes, nanocubes and so on can be forthrightly fabricated by fine tuning the solvent polarity and or the shuttling movement of the macrocycle in THF/water mixture to manipulate the self-assembly processes. Self-assembly reveals that nanocubes can only be constructed by TB3+ and RZ3+ molecules in aqueous media but not by RZ+ and RZ2+ under similar conditions. The fascinating nanocubes was mainly controlled precisely by two major factors i.e., Tz cationic units and aqueous medium. It is worth mentioning that, exotic shape organic nanocubes were seldomly reported in rotaxane-based nano-objects owing to unfavorable thermodynamics for nanocubes formation. This study highlights the benefits of using Tz cationic units, which not only serve as secondary molecular station but also control the self-assembly process to form nanocubes in aqueous medium, providing a new avenue for nanomaterials technology and further enriching the applications of mechanically interlocked molecules (MIMs).

High magnetic field-engineered high mass loading sulfides with well-ordered hierarchical nanostructures for all-solid-state supercapacitors

Low energy density is becoming the largest sore point of supercapacitors. Constructing all-solid-state asymmetric supercapacitors (AASCs) with high mass loading and high utilization of electrochemically active materials can largely remedy the drawback. Herein, well-ordered hierarchical porous NiCo2S4 pine needles on carbon cloth (CC) with a loading mass as high as 10.76 mg cm−2 (NCS-12 T) were fabricated by low-temperature topotactic vulcanization of the high-mass-loading (Ni, Co)(CO3)0.5(OH)·0·.11H2O precursor (NCCH-12 T) yielded under 12 T high magnetic field (HMF). The loading mass on each CC tends towards equivalence and increases remarkably with the rise of HMF by guaranteeing sufficient ion supply. Impressively, a high overall capacitance of 10.46F cm−2 at 5 mA cm−2 was achieved without sacrificing the specific capacitance and rate capability that are slightly superior to those of the low mass loading NiCo2S4 electrodes instead. The striking electrochemical performances are ascribed to the available ion and electron transport in the whole electrode, which results from the construction of three-dimensional hierarchical porous nanostructures and HMF-derived well-ordered and uniform deposition via boosting ion transport. Finally, the NCS-12 T-based AASCs with high mass loading exhibit a high energy density of 280 μWh cm−2 at the power density of 1.71 mW cm−2, exceeding most state-of-the-art supercapacitors.

Fabrication of oxygen-vacancy abundant MnO2 nanowires@ NiMnxOy-δ nanosheets core-shell heterostructure for capacity supercapacitors

Structure instability and poor electrical conductivity are two major obstacles to realizing high performance of MnO2-based pseudocapacitor material. The construction of unique hierarchical core-shell nanostructures, therefore, plays an important role in the efficient enhancement of the rate capacity and the stability of this material. Herein, a stable MnO2@NiMnxOy-δ core-shell heterostructure is prepared via a simple liquid-phase reaction combined with heat-treatment method, composed of ultrathin NiMnxOy-δ nanosheets with oxygen vacancies uniformly growing on the surface of ultralong MnO2 nanowires. Electrochemical test results show that the electrode exhibits a specific capacitance of 463.5 C g−1 at 1 A g−1 and has an excellent capacitance retention as high as 94.9% after 20,000 cycles. Compared with the MnO2@NiMnxOy nanowires, the introduction of oxygen vacancies in the ultrathin nanosheets of the MnO2@NiMnxOy-δ core-shell heterostructure can provide a large number of surface active sites to accelerate electron/ions transport during electrochemical reaction. Moreover, the interfacial behavior of the electrode reaction can be also adjusted due to the potential synergistic effect between one-dimensional nanowires and two-dimensional nanosheets, further the MnO2@NiMnxOy-δ core-shell heterostructure demonstrating the superior cyclic stability.