Core-shell Nanocomposites Research Articles

Core-shell structure of reduced graphene oxide@Ag–TiO2 for photocatalytic H2O splitting and CH3OH dehydrogenation under UV light irradiation

The H2 production from water-splitting and dehydrogenation of waste alcohols is widely investigated in current years to find out greener, and more efficient photocatalyst materials. Reduced graphene oxide (rGO; 1-10 wt%) coated TiO2 and Ag(1 wt%)-TiO2 core-shell nanocomposites are fabricated for enhanced photocatalytic H2 production from H2O-splitting and CH3OH-dehydrogenation under UV irradiation. These rGO@TiO2 and rGO@Ag–TiO2 catalysts are characterized by XRD, Raman, FE-SEM, HR-TEM, XPS, BET, CV, EDS-mapping, PL, and UV–vis DRS for morphological, structural, and optical properties. After rGO(1-3 wt%) coating over TiO2, the H2 amount is increased from 5 to 14 mmol for H2O-splitting and 13–83 mmol via CH3OH-dehydrogenation during 5 h UV irradiation, respectively. Due to the synergetic effect of rGO and Ag, core-shell rGO(2-4 wt%) coated Ag–TiO2 produced the highest amount of 108–133 mmol of H2 from water-splitting and 440–450 mmol from CH3OH-dehydrogenation during 7 and 5 h UV irradiation, respectively. The work illustrates the potential of Ag-deposition and rGO-coating over TiO2 for efficient H2 production.

Synthesis and evaluation of core–shell nanocomposites for the photodegradation of liner alkyl-benzene sulfonate water contaminations

Linear alkyl-benzene sulfonate surfactants (LAS) are a major pollutant source of sewage and wastewater. They trigger severe impact on the environmental fauna and flora. Current research explores the synthesis of three different core–shell nanocomposites (CSNCs) containing titania through an inexpensive oxidative polymerization technique. The fabricated CSNCs were evaluated for the photocatalytic degradation of LAS water contaminations. The selected CSNCs investigated for this study were the TiO2/poly(aniline-co-pyrrole) and TiO2/ poly(aniline-co-3-Me-thiophene) as well as the TiO2/terpolymer (aniline-pyrrole-m-aminobenzoic acid). The structure of the formed nanocomposites was confirmed by varied characterization spectroscopy. The core–shell structure of the nanocomposites was confirmed by scanning electron micrographs and transmission electron microscopy. The CSNCs exhibited intensive photo catalytic degradation efficacy toward LAS under visible light exposure in comparison with the exposure in their absence. The parameters optimizing their photovoltaic degradation efficiency were assessed. The presented approach implies that an effective, economical, and environmentally friendly synthetic setup was achieved to produce novel CSNCs with high potential as LAS photodegradation agents.

Hexagonal crystalline nanofillers reinforced composite carbon nanofibers with optimized crystal structure and improved mechanical properties

The mechanical properties of carbon nanofibers (CNFs) are always restricted by their disorganized crystal structures. Herein, this paper utilizes two typical hexagonal crystalline flake materials, nanoscale flake graphite (NG) and hexagonal nitride boron (BN), as nanofillers to optimize the crystal domains of CNFs and achieves enhancement in fiber strength, modulus and toughness. For this purpose, in situ polymerization technique is developed for the rapid and uniform mixing of nanofillers with polyacrylonitrile (PAN) precursors of CNFs. The nanofillers are exfoliated in this process and wrapped with PAN to prevent potential agglomeration. The obtained core-shell nanocomposites can be produced into composite CNFs via electrospinning, stabilization and carbonization. Based on the attraction effect, the dispersed nanofillers can organize PAN molecular chains into oriented crystalline fibrils in as-spun nanofibers and accelerate their transformation to more ladder structures in stabilized nanofibers. On this basis, NG is shown to act as the templating and nucleating agent to promote the formation, growth and compact stacking of graphitic planes in CNFs. BN also improves fiber crystallinity, while its limited templating effect leads to looser and finer crystal domains. As a result, NG-doped CNFs have significantly improved strength and modulus, and BN-doped CNFs possess simultaneously enhanced strength and toughness.

Design of CuO @ SiO2 core shell nanocomposites and its applications to photocatalytic degradation of Rhodamine B dye

In this work, photocatalytic behavior of CuO@SiO2 core shell nanocomposites (CuO@SiO2 CSNs) is reported. The formation and structure of the prepared samples were confirmed using powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and High resolution transmission electron microscopy (HRTEM) techniques. UV analysis revealed that the incorporation of SiO2 onto CuO resulted in a notable decrease in the bandgap energy from 3.2 eV to 2.8 eV, along with a reduction in the rate of electron-hole recombination and in consequence of that CuO@SiO2 CSNs demonstrated an impressive degradation rate of 92% for Rhodamine B (Rh B), while CuO Nanoparticles (NPs) exhibited a relatively lower rate of 80%. The BET surface area analysis revealed that CuO@SiO2 CSNs had a greater surface area of 68.418 m³/g as opposed to 9.364 m³/g for CuO NPs, which contributed to the former's remarkable catalytic performance.

Core–shell- shell structured P(Ani-co-Py)/NiF-grafted-(Go-PPD)-PPy nanocomposites prepared via two steps polymerization of conducting polymer for sensitive Tl3+detection

In this research, a newly developed structure consisting of a shell made of (Graphene oxide-Paraphenylenediamine)/Polypyrrole (Go-PPD)-PPy was successfully synthesized on a binary poly(aniline-co-o-pyrrole)/NiFe2O4 core-shell nanocomposite, known as P(Ani-co-Py)/NiF NCs. The synthesis process involved a two-step approach, starting with the in-situ oxidative polymerization of the copolymer P(Ani-co-Py) on NiF nanoparticles (NPs). This was followed by a subsequent in-situ oxidative polymerization of (Go-PPD)-PPy on the P(Ani-co-Py)/NiF core-shell NCs, resulting in the formation of PPy-(Go-PPD)/P(Ani-co-Py)/NiF NCs with a core-shell-shell structure. In this method, the developed sensor designed specifically for Tl3+ demonstrated high effectiveness and reliability in detecting Tl3+ ions within a phosphate buffer medium. During the fabrication process of the sensor probe, the stability of the synthesized PPy-(Go-PPD)/P(Ani-co-Py)/NiF NCs on a glassy carbon electrode (GCE) was enhanced significantly by incorporating nafion, a 5% suspension in ethanol. A calibration curve was established by drawing the current toward the concentration of Tl3+, showing a linear relationship. By looking at the maximum linear portion of the calibration curve, a linear dynamic range of 0.1 nM to 0.01 mM was determined. Sensor sensitivity has been calculated as 1.06 µAµM−1cm−2, by setting the slope of the calibration curve and GCE (the surface area of the glassy carbon electrode), which was measured as 0.0316 cm2. The lower limit of detection (LOD) was determined to be 92.09±4.60 pM based on a signal-to-noise ratio of 3. Limit of quantification (LOQ) is calculated as 279.06 pM from 10*(LOD)/3.3. Finally, the proposed Tl3+ ion sensor's performance was validated by analyzing real environmental samples, and satisfactory results were obtained.

A simple synthesis of a core-shell structure PPy-Au nanocomposite for immunosensing of C-reactive protein

High-sensitivity C-reactive protein (hs-CRP) is an inflammatory biomarker and can accurately predict the development of cardiovascular disease (CVD). We synthesized a core-shell structure PPy-Au nanocomposite in situ by chemically oxidizing pyrrole (Py) with HAuCl4 and the produced Au nanoparticles realized the doping in the polymerization. Analysis of morphology and energy spectrum as well as electrochemical characterization confirmed the successful one-pot synthesis. The conductive polymers with porous structure provide abundant sites for anti-CRP binding and effectively enhanced the sensitivity of the label-free BSA/anti-CRP/PPy-Au/GCE immunosensor. Its analytical performance was observed using differential pulse voltammetry (DPV), with a linear range from 0.0005 to 60 μg mL−1 and a detection limit of 0.17 ng mL−1. The platform demonstrated satisfactory selectivity, stability, and reproducibility. To validate its clinical application, we detected CRP in human serum samples with a recovery rate of 101.00–105.95% and investigated the consistency of the developed method and immunoturbidimetry with a deviation between −1.2% and +3.2%, suggesting great potential for use in point-of-care testing (POCT).

Highly Uniform Spherical MoO2-MoO3/Polypyrrole Core-Shell Nanocomposite as an Optoelectronic Photodetector in UV, Vis, and IR Domains.

A highly uniform spherical MoO2-MoO3/polypyrrole core-shell nanocomposite has been successfully synthesized as an optoelectronic photon sensing material, capable of detecting light in the UV, Vis, and IR domains. The nanocomposite is prepared through the oxidation of pyrrole using Na2MoO4, resulting in a uniform spherical morphology that has been confirmed by TEM, theoretical modeling, and SEM analyses. This morphology contributes to its promising optical behavior, characterized by a small bandgap of 1.36 eV. The optoelectronic photosensing capability of the nanocomposite has been evaluated across the UV, Vis, and IR spectra, demonstrating high efficiency. The photoresponsivity R values indicate the ability of the nanocomposite to generate hot electrons in response to incident photons. With an R value of 4.15 mA·W-1 at 440 nm, this optoelectronic device exhibits considerable promise for integration into an advanced technological apparatus. The detection (D) value of 9.30 × 108 Jones at 440 nm further confirms the high sensitivity in the Vis region. The excellent stability of the device can be attributed to the inherent MoO2-MoO3 oxide and Ppy polymer materials. This stability has been demonstrated through reproducibility studies and current-voltage measurements under various optical conditions. The combination of stability, efficiency, and sensitivity makes this optoelectronic device well suited for light sensing applications in both industrial and commercial settings. Its promising performance opens up opportunities for advancements in various fields requiring accurate and reliable light detection.

High-performance NiO@Fe3O4 magnetic core-shell nanocomposite for catalytic ozonation degradation of pharmaceutical pollution.

Pharmaceuticals that are present in superficial waters and wastewater are becoming an ecological concern. Therefore, it is necessary to provide high-performance methods to limit the harmful ecological effects of these materials to achieve a sustainable environment. In this research, NiO@Fe3O4 nanocomposite was prepared by the co-precipitation method and utilized in the catalytic ozonation process for the degradation of 1-cyclopropyl-6-fluoro-4-oxo-7-piperazin-1-yl-quinoline-3-carboxylic acid (ciprofloxacin antibiotic), for the first time. The influencing parameters in the degradation process were analyzed and optimized via response surface methodology (RSM). The optimal ciprofloxacin removal efficiency (100%) was found at pH = 6.5, using 7.5 mg of the NiO@Fe3O4 nanocatalyst and 0.2 g L-1 h-1 ozone (O3) flow, applied over 20 min. Results showed a significant synergistic effect in the analyzed system, which makes the proposed catalytic ozonation process more efficient than using the catalyst and ozone separately. Also, based on the kinetic analysis data, the catalytic ozonation process followed the pseudo-first-order model. In addition, the nanocatalyst showed high recyclability and stability (88.37%) after five consecutive catalytic ozonation process cycles. In conclusion, the NiO@Fe3O4 nanocatalyst/O3 system can be effectively used for the treatment of pharmaceutical contaminants.

Application of a Perovskite NIR-LED with Highly Stable FAPbI3@SiO2 Core-Shell Nanocomposites in a SPR Sensing Platform.

In recent years, the demand for detection and diagnostic methods has consistently risen due to the aging of the population and the increase in the number of patients with chronic diseases. Label-free biomedical detection techniques have emerged as indispensable instruments for diagnosing a variety of diseases. The development of label-free and highly sensitive near-infrared (NIR) biomedical detection technology has attracted considerable attention. As a label-free, swift, and cost-effective analytical technique, it has demonstrated immense potential for a wide range of applications. We successfully assembled FAPbI3 near-infrared perovskite quantum dots (NIPQDs) into SiO2 shells using a rapid room-temperature atmospheric synthesis method, obtaining monodisperse FAPbI3@SiO2 nanocomposites (NCs) with a high photoluminescence quantum yield (PLQY) of 72%. Additionally, the incorporation of hydrophobic multi-branched trioctylphosphine oxide effectively passivated the surface defects of FAPbI3 NIPQDs and suppressed the hydrolysis rate of tetraethoxysilane, enabling the formation of a highly stable and high PLQY nanoscale-particle level within the FAPbI3@SiO2 core-shell structure. Notably, we successfully incorporated FAPbI3@SiO2 core-shell NCs onto InGaN blue chip as NIR excitation light sources for surface plasmon resonance sensing platforms, providing a novel platform for bioanalytical detection. With a detection sensitivity of 6302.5 nm/RIU, the system demonstrated high sensitivity, stability, and dependability. This achievement expands the biomedical research field's capacity for diagnosis, monitoring, and treatment.

The advancing of polymeric core-shell ZnO nanocomposites containing 5-fluorouracil for improving anticancer activity in colorectal cancer.

The study investigated the use of 5-fluorouracil-loaded ZnO nanocomposites (5-FU/Gd-ZnO NCs) as a potential treatment for cancer. 5-FU is a commonly used drug for cancer treatment but has undesirable side effects. The materials were characterized using various techniques, including PXRD, FTIR, FESEM, TEM, DLS, £-potential, and AFM. The data showed that the nanocomposites had a plate-like agglomeration with particle diameters ranging from 317.6 to 120.1nm. The IC50 value of 5-FU-ZnO, which inhibits cell growth, was found to be 1.85ppm. The effects of 5-FU-ZnO on inflammatory markers were also examined. While 5-FU increased the levels of TNF-a and IL-1b, the nanocomposites were able to reduce these levels. Additionally, the 5-FU/Gd-ZnO-NCs group showed an increase in thiol levels and a decrease in catalase and superoxide dismutase levels. Flow cytometry results showed that 5-FU, ZnO-NCs, and 5-FU/Gd-ZnO-NCs did not have any additive or synergistic effects on the suppression or eradication of cancer cells. In vivo, experiments showed that the 5-FU/Gd-ZnO NCs had similar necrotic characteristics and reduced fibrosis and collagen deposition compared to the free medication. The nanocomposites also exhibited higher antioxidative activity and lower inflammatory responses compared to the 5-FU group. It was shown that 5-FU/Gd-ZnO-NCs successfully inhibit cell proliferation. The in vivo results were comparable to those obtained with free 5-FU, suggesting the potential of these nanocomposites as therapeutic agents.

NIR laser-activated multifunctional nanocomposites for cascade low-temperature photothermal and oxygen-irrelevant thermodynamic therapy

Osteosarcoma, occurring most frequently in adolescents, are highly malignant bone tumor and prone to develop local recurrence and long-distance metastasis. Therefore, new comprehensive therapeutic strategies for osteosarcoma are urgently needed. Different from traditional photothermal therapy (PTT), low temperature PTT (LTPTT) not only brings less heat damages to the surrounding normal tissues but also prevent tumor metastasis. Nevertheless, its therapeutic effects are severely attenuated due to the tumor thermo-resistance induced by the overexpression of heat shock protein (HSP). In our work, an acid-responsive core–shell nanocomposite was fabricated for cancer therapy. The nanoplatform can independently encapsulate alkyl radical initiator 2,2-azobis[2-(2-imidazolin-2-yl) propane]-dihydroch-loride (AIPH) in the mesoporous polydopamine (MPDA) core and HSP inhibitor (gambogic acid, GA) in the zeolite imidazolate framework-8 (ZIF-8) microporous shell, called MPDA/AIPH@ZIF-8/GA (MAZG), which could achieve the combined functions of LTPTT and thermodynamic therapy (TDT). After endocytosing by tumor cells, the pH-responsive degradation of the ZIF-8 coating stimulates the rapid release of GA, which can effectively inhibit HSP expression in advance, and then simultaneously enhanced the therapeutic efficacy of LTPTT. Further, both in vitro and in vivo experiments have demonstrated that the as-synthesized MAZG nanocomposite exhibited favorable biosafety and remarkable tumor growth inhibition.

Fabrication of versatile Ag-P/Ppy core-shell nanocomposite: Adsorption efficacy for chromium (VI) removal and assessment of antioxidant and antibacterial activities

This study reports the synthesis, via in-situ chemical oxidative polymerisation, of conducting polymer-based silver phosphate Polypyrrole (Ag-P/Ppy) core-shell nanocomposite, exhibiting antioxidant and antibacterial characteristics, for the adsorption of chromium (VI) ions from aqueous solutions. Filtering away Cr (VI) ions efficiently also improves the filtered water with antibacterial and antioxidant properties. P-XRD, ATR-FTIR, FESEM, EDAX, TEM, zeta potential, TGA, and BET studies characterized Ag-P/Ppy. The core-shell nanostructure of Ag-P/Ppy was determined by TEM micrographs, which indicated the presence of an Ag-P core and a Ppy shell. pH value, adsorbent dose, stirring rate, contact time, and Cr (VI) pollutant concentration, were investigated as potential influencing factors. At pH 2, 99.4 % of Cr(VI) was removed in 55 min. The adsorption kinetics was effectively depicted by a pseudo-second-order kinetics model, signifying that chemisorption played a momentous role in the total adsorption capacity. Freundlich, Temkin, Redlich-Peterson, and Sips isotherm models were fitted to adsorption data. Temkin and Redlich-Peterson models have a higher (0.99) correlation coefficient than Freundlich (0.95) and Sips (0.98). The maximum adsorption capacity (qm) evaluated using the Sips model was 138.5 mg g−1, which was quite close to the 130.55 mg g−1 value obtained from experiments. The manufactured nanocomposite showed 91.2 % radical scavenging activity in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Antibacterial activity of the Ag-p/Ppy core-shell nanocomposite contrary to gram-positive (S. aureus) and gram-negative (P. aeruginosa, E. coli, and K. pneumoniae) bacteria was assessed by means of the agar well diffusion technique. Compared to the positive control, it inhibited S. aureus, E. coli, K. Pneumoniae, and P. Aeruginosa by 82.35 %, 79.5 %, 63.63 %, and 76.7 % respectively. Therefore, the Ag-P/Ppy core-shell nanocomposite has the potential as a potent and versatile adsorbent for the exclusion of Cr (VI) ions from water.

Tailoring Morphology in Hydrothermally Synthesized CdS/ZnS Nanocomposites for Extraordinary Photocatalytic H2 Generation via Type-II Heterojunction

CdS@ZnS core shell nanocomposites were prepared by a one-pot hydrothermal route. The morphology of the composite was tuned by simply changing the Zn2+ precursor concentration. To characterize the samples prepared, various techniques were employed, including XRD, FESEM, TEM, XPS and UV-vis DRS. The band gaps of CdS and ZnS were measured to be 2.26 and 3.32 eV, respectively. Compared with pure CdS, the CdS@ZnS samples exhibited a slight blue shift, which indicated an increased band gap of 2.29 eV. The CdS@ZnS core shell composites exhibited efficient photocatalytic performance for H2 generation under simulated sunlight illumination in contrast to pure CdS and ZnS. Additionally, an optimized H2 generation rate (14.44 mmol·h−1·g−1cat) was acquired at CdS@ZnS-2, which was approximately 4.6 times greater than that of pure CdS (3.12 mmol·h−1·g−1cat). Moreover, CdS@ZnS heterojunction also showed good photocatalytic stability. The process of charge separation over the photocatalysts was investigated using photoelectrochemical analysis. The findings indicate that the CdS@ZnS nanocomposite has efficient charge separation efficiency. The higher H2 generation activity and stability for CdS@ZnS photocatalysts can be attributed to the intimate interface in the CdS@ZnS core–shell structure, which promoted the light absorption intensity and photoinduced charge separation efficiency. It is expected that this study will offer valuable insights into the development of efficient core shell composite photocatalysts.

Aqueous Processable One-Dimensional Polypyrrole Nanostructured by Lignocellulose Nanofibril: A Conductive Interfacing Biomaterial.

One-dimensional (1D) nanomaterials of conductive polypyrrole (PPy) are competitive biomaterials for constructing bioelectronics to interface with biological systems. Synergistic synthesis using lignocellulose nanofibrils (LCNF) as a structural template in chemical oxidation of pyrrole with Fe(III) ions facilitates surface-confined polymerization of pyrrole on the nanofibril surface within a submicrometer- and micrometer-scale fibril length. It yields a core-shell nanocomposite of PPy@LCNF, wherein the surface of each individual fibril is coated with a thin nanoscale layer of PPy. A highly positive surface charge originating from protonated PPy gives this 1D nanomaterial a durable aqueous dispersity. The fibril-fibril entanglement in the PPy@LCNFs facilely supported versatile downstream processing, e.g., spray thin-coating on glass, flexible membranes with robust mechanics, or three-dimensional cryogels. A high electrical conductivity in the magnitude of several to 12 S·cm-1 was confirmed for the solid-form PPy@LCNFs. The PPy@LCNFs are electroactive and show potential cycling capacity, encompassing a large capacitance. Dynamic control of the doping/undoping process by applying an electric field combines electronic and ionic conductivity through the PPy@LCNFs. The low cytotoxicity of the material is confirmed in noncontact cell culture of human dermal fibroblasts. This study underpins the promises for this nanocomposite PPy@LCNF as a smart platform nanomaterial in constructing interfacing bioelectronics.

Porous prussian blue analogs derived nickel-iron bimetallic phosphide nanocubes on conductive hollow mesoporous carbon nanospheres for stable and flexible high-performance supercapacitor electrode

Nickel-iron bimetallic phosphide (Ni-Fe-P) is the ideal battery-type materials for supercapacitor in virtue of high theoretical specific capacitance. Nevertheless, its actual adhibition is astricted on account of inferior rate capability and cyclic stability. Herein, we constructed hierarchical core–shell nanocomposites with hollow mesoporous carbon nanospheres (HMCS) packaged via prussian blue analogs derived Ni-Fe-P nanocubes (Ni-Fe-P@HMCS), as a positive electrode for hybrid supercapacitor (HSC). Profiting from the cooperative effects of Ni-Fe-P nanocubes with small size and good dispersibility, and HMCS with continuously conductive network, the Ni-Fe-P@HMCS composite electrode with abundantly porous architectures presents an ultrahigh gravimetric specific capacity for 739.8 C g−1 under 1 A g−1. Specially, the Ni-Fe-P@HMCS electrode presents outstanding rate capability of 78.4% (1 A g−1 to 20 A g−1) and cyclic constancy for 105% after 5000 cycles. Density functional theory implies that the composite electrode possesses higher electrical conductivity than bare Ni-Fe-P electrode by reason of the incremental charge density, and the electrons transferring from NiFe3P4 to HMCS layers. Additionally, the assembled Ni-Fe-P@HMCS//HMCS HSC facility delivers the high energy density for 64.1 Wh kg−1, remarkable flexibility and mechanical stability. Thus, this work proffers a viable and efficacious measure to construct ultra-stability electrode for high-performance portable electronic facilities.

Innovative Metal-Organic Frameworks for Targeted Oral Cancer Therapy: A Review

Metal-organic frameworks (MOFs) have proven to be very effective carriers for drug delivery in various biological applications. In recent years, the development of hybrid nanostructures has made significant progress, including developing an innovative MOF-loaded nanocomposite with a highly porous structure and low toxicity that can be used to fabricate core-shell nanocomposites by combining complementary materials. This review study discusses using MOF materials in cancer treatment, imaging, and antibacterial effects, focusing on oral cancer cells. For patients with oral cancer, we offer a regular program for accurately designing and producing various anticancer and antibacterial agents to achieve maximum effectiveness and the lowest side effects. Also, we want to ensure that the anticancer agent works optimally and has as few side effects as possible before it is tested in vitro and in vivo. It is also essential that new anticancer drugs for cancer treatment are tested for efficacy and safety before they go into further research.

ZIF-67 derived porous core-shell nanocomposites for high-efficiency electromagnetic absorption

N-doped porous core-shell nanocomposite is considered to be a competent candidate for the absorbing of electromagnetic wave (EMW). In this work, polydopamine (PDA) wrapped ZIF-67 (Z@P) precursors with the core-shell structure were obtained through ZIF-67 triggered dopamine self-polymerization. After high-temperature pyrolysis treatment, the N-doped graphitized carbon layers wrapped cobalt (Co@CNs) absorber with porous structure was obtained, which exhibited high efficiency and adjustable EMW absorbing properties. The minimum reflection loss (RLmin) of Co@CN-60 approached −59.08 dB at 17.7 GHz with a thickness of 1.7 mm. The effective absorption bandwidth (EAB) reached 5.8 GHz with a corresponding thickness of 2.3 mm. Besides, the RLmin of Co@CN-90 reaches −44.07 dB at 14.5 GHz (thickness 2.0 mm), and the EAB is 5.9 GHz. Therefore, the porous core-shell Co@CNs nanocomposite is expected to be a promising EMW absorption material.

Controllable Synthesis of MIL-101(Cr)@TiO2 Core–Shell Nanocomposites for Enhanced Photocatalytic Activity

Controllable Synthesis of MIL-101(Cr)@TiO₂ Core–Shell Nanocomposites for Enhanced Photocatalytic Activity

Synthesis of Fe3O4@SiO2 core-shell nanocomposite for fast removal of methylene blue from water

In this work, Fe3O4@SiO2 core-shell nanocomposites were successfully synthesised via a simple co-precipitation method. X-ray diffraction pattern of Fe3O4@SiO2 clearly shows the existence of a main phase of Fe3O4, beside an amorphous structure of SiO2. The core-shell Fe3O4@SiO2 with an average particle size in the range of 10-20 nm is observed by SEM and TEM images. FTIR spectrum illustrates the Fe-O and Si-O-Si bonds in the sample, indicating the formed nanocomposite of Fe3O4@SiO2. The brunauer, emmett and teller surface area analysis of the Fe3O4@SiO2 sample is 4 times higher than that of Fe3O4. The vibrating sample magnetometer data indicated that the saturation of Fe3O4@SiO2 (23.1 emu/g) is strongly decreased in comparison with Fe3O4 nanoparticles (58.1 emu/g), explained by the shielding of the SiO2 nonmagnetic materials. The methylene blue adsorption efficiency in the saturation adsorption time of 60 min for Fe3O4@SiO2nanocomposite is 88.8%, which is 3 times higher than that of Fe3O4 nanoparticles. A model explaining the enhanced mechanism in methylene blue adsorption efficiency of Fe3O4@SiO2 nanocomposite is proposed. The obtained results show that the synthesised Fe3O4@SiO2 nanocomposite has great potential in dye removal applications from water.

Defective core–shell NiCo2S4/MnO2 nanocomposites for high performance solid-state hybrid supercapacitors

The roles of oxygen vacancies to enhance the electrochemical performance were not clearly explained in comprehensive research. Herein, the vertically oriented NiCo2S4/MnO2 core–shell nanocomposites are in situ grown on the nickel foam (NF) surface and activated by oxygen vacancy engineering via a chemical reduction method. The scanning electron microscope (SEM) and transmission electron microscope (TEM) results show the shell-MnO2 is well coated on the core-NiCo2S4. The hierarchical core–shell nanostructures synergistically increase conductivity and provide rich faradaic redox chemical reactions. Moreover, the density functional theory (DFT) calculations further indicate that the electronic properties and structure properties in NiCo2S4/MnO2 electrode of reduction for 60 min (NiCo2S4/MnO2-60) are effectively adjusted by introducing oxygen vacancies. Impressively, the NiCo2S4/MnO2-60 electrode delivers substantially appreciable areal capacity of 2.13 mAh·cm−2 couple with superior rate capability. The as-prepared high-performance electrode material can assemble into solid-state hybrid supercapacitor. The fabricated NiCo2S4/MnO2-60//AC device exhibits an exceptional energy density of 43.16 Wh·kg−1 at a power density of 384.21 W·kg−1 and satisfactory cyclic stability of 92.1 % at current density of 10 mA·cm−2 after 10,000 cycles. In general, the work demonstrates the significance of NiCo2S4/MnO2-60 as a highly redox active electrode material for future practical application in supercapacitors.