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1.
Core–shell magnetic porous microspheres have wide applications in drug delivery, catalysis and bioseparation, and so on. However, it is great challenge to controllably synthesize magnetic porous microspheres with uniform well‐aligned accessible large mesopores (>10 nm) which are highly desired for applications involving immobilization or adsorption of large guest molecules or nanoobjects. In this study, a facile and general amphiphilic block copolymer directed interfacial coassembly strategy is developed to synthesize core–shell magnetic mesoporous microspheres with a monolayer of mesoporous shell of different composition (FDUcs‐17D), such as core–shell magnetic mesoporous aluminosilicate (CS‐MMAS), silica (CS‐MMS), and zirconia‐silica (CS‐MMZS), open and large pores by employing polystyrene‐block‐poly (4‐vinylpyridine) (PS‐b‐P4VP) as an interface structure directing agent and aluminum acetylacetonate (Al(acac)3), zirconium acetylacetonate, and tetraethyl orthosilicate as shell precursors. The obtained CS‐MMAS microspheres possess magnetic core, perpendicular mesopores (20–32 nm) in the shell, high surface area (244.7 m2 g?1), and abundant acid sites (0.44 mmol g?1), and as a result, they exhibit superior performance in removal of organophosphorus pesticides (fenthion) with a fast adsorption dynamics and high adsorption capacity. CS‐MMAS microspheres loaded with Au nanoparticles (≈3.5 nm) behavior as a highly active heterogeneous nanocatalyst for N‐alkylation reaction for producing N‐phenylbenzylamine with a selectivity and yields of over 90% and good magnetic recyclability.  相似文献   

2.
High-capacity metal oxides based on non-toxic earth-abundant elements offer unique opportunities as advanced anodes for lithium-ion batteries (LIBs). But they often suffer from large volumetric expansion, particle pulverization, extensive side reactions, and fast degradations during cycling. Here, an easy synthesis method is reported to construct amorphous borate coating network, which stabilizes conversion-type iron oxide anode for the high-energy-density semi-solid-state bipolar LIBs. The nano-borate coated iron oxide anode has high tap density (1.6 g cm−3), high capacity (710 mAh g−1 between 0.5 – 3.0 V, vs Li/Li+), good rate performance (200 mAh g−1 at 50 C), and excellent cycling stability (≈100% capacity resention over 1,000 cycles at 5 A g−1). When paired with high-voltage cathode LiCoO2, it enables Cu current collector-free pouch-type classic and bipolar full cells with high voltage (7.6 V with two stack layers), achieving high energy density (≈350 Wh kg−1), outstanding power density (≈6,700 W kg−1), and extended cycle life (75% capacity retention after 2,000 cycles at 2 C), superior to the state-of-the-art high-power LIBs using Li4Ti5O12 anode. The design and methodology of the nanoscale polyanion-like coating can be applied to other metal oxides electrode materials, as well as other electrochemical materials and devices.  相似文献   

3.
Silica spheres with sub-micrometer sized solid core and mesoporous shell (SCMS) structure were synthesized, and aluminum was incorporated into the mesoporous shell framework by impregnation method to generate SCMS aluminosilicate (AlSCMS) nanospheres. The impregnation of aluminum into the SCMS spheres generates the acid sites on the framework due to the presence of Al3+ ions. The AlSCMS was then used to support molybdenum ion species on the mesoporous shell framework. A solid-state reaction of MoO3 with AlSCMS followed by thermal reduction generated paramagnetic Mo(V) species. The dehydration produced a Mo(V) species that is characterized by electron spin resonance with g e > g  > g ||. The structural properties of active sites in the AlSCMS were characterized by means of XRD, UV–Vis, 27Al MAS NMR, FT-IR, and energy dispersive X-ray spectrometric measurements. Upon O2 adsorption, the Mo(V) ESR signal intensity decreased, and a new O2 radical was generated. The Mo species in the dehydrated Mo-AlSCMS is found to exist as oxo-molybdenum species, (MoO2)+ or (MoO)3+. Since the AlSCMS has a low framework negative charge, the MoO2 + with a low positive charge can be easily stabilized and thus seems to be more probable in the AlSCMS framework.  相似文献   

4.
SiOx is a promising next-generation anode material for lithium-ion batteries. However, its commercial adoption faces challenges such as low electrical conductivity, large volume expansion during cycling, and low initial Coulombic efficiency. Herein, to overcome these limitations, an eco-friendly in situ methodology for synthesizing carbon-containing mesoporous SiOx nanoparticles wrapped in another carbon layers is developed. The chemical reactions of vinyl-terminated silanes are designed to be confined inside the cationic surfactant-derived emulsion droplets. The polyvinylpyrrolidone-based chemical functionalization of organically modified SiO2 nanoparticles leads to excellent dispersion stability and allows for intact hybridization with graphene oxide sheets. The formation of a chemically reinforced heterointerface enables the spontaneous generation of mesopores inside the thermally reduced SiOx nanoparticles. The resulting mesoporous SiOx-based nanocomposite anodes exhibit superior cycling stability (≈100% after 500 cycles at 0.5 A g−1) and rate capability (554 mAh g−1 at 2 A g−1), elucidating characteristic synergetic effects in mesoporous SiOx-based nanocomposite anodes. The practical commercialization potential with a significant enhancement in initial Coulombic efficiency through a chemical prelithiation reaction is also presented. The full cell employing the prelithiated anode demonstrated more than 2 times higher Coulombic efficiency and discharge capacity compared to the full cell with a pristine anode.  相似文献   

5.
Hard carbon is generally accepted as the choice of anode material for sodium-ion batteries. However, integrating high capacity, high initial Coulombic efficiency (ICE), and good durability in hard carbon materials remains challenging. Herein, N-doped hard carbon microspheres (NHCMs) with abundant Na+ adsorption sites and tunable interlayer distance are constructed based on the amine–aldehyde condensation reaction using m-phenylenediamine and formaldehyde as the precursors. The optimized NHCM-1400 with a considerable N content (4.64%) demonstrates a high ICE (87%), high reversible capacity with ideal durability (399 mAh g−1 at 30 mA g−1 and 98.5% retention over 120 cycles), and decent rate capability (297 mAh g−1 at 2000 mA g−1). In situ characterizations elucidate the adsorption–intercalation-filling sodium storage mechanism of NHCMs. Theoretical calculation reveals that the N-doping decreases the Na+ adsorption energy on hard carbon.  相似文献   

6.
1D carbon nanotubes have been widely applied in many fields, such as catalysis, sensing and energy storage. However, the long tunnel-like pores and relatively low specific surface area of carbon nanotubes often restrict their performance in certain applications. Herein, a dual-silica template-mediated method to prepare nitrogen-doped mesoporous carbon nanotubes (NMCTs) through co-depositing polydopamine (both carbon and nitrogen precursors) and silica nanoparticles (the porogen for mesopore formation) on a silica nanowire template is proposed. The obtained NMCTs have a hierarchical pore structure of large open mesopores and tubular macropores, a high specific surface area (1037 m2 g−1), and homogeneous nitrogen doping. The NMCT-45 (prepared at an interval time of 45 min) shows excellent performance in supercapacitor applications with a high capacitance (373.6 F g−1 at 1.0 A g−1), excellent rate capability, high energy density (11.6 W h kg−1 at a power density of 313 W kg−1), and outstanding cycling stability (98.2% capacity retention after 10 000 cycles at 10 A g−1). Owing to the unique tubular morphology, hierarchical porosity and homogeneous N-doping, the NMCT also has tremendous potential in electrochemical catalysis and sensing applications.  相似文献   

7.
《Advanced Powder Technology》2021,32(10):3904-3914
NaP1 zeolite, using red mud (RM) as raw material, was successfully prepared via alkali fusion and hydrothermal method. NaP1 zeolite, which was a mesoporous material, had specific surface area and pore diameter of 79.3 m2·g−1 and 7.26 nm, respectively. NaP1 zeolite had excellent adsorption properties. Under the optimum adsorption conditions, methylene blue (MB) was adsorbed through NaP1 zeolite, the adsorption capacity was 48.7 mg·g−1 and the removal efficiency was 97.1%. The adsorbent was regenerated with sodium chloride as eluent. The adsorption capacity of the adsorbent regenerated three times still was satisfactory 34.53 mg·g−1, which showed the excellent stability performance from NaP1 zeolite. The adsorption conformed to the pseudo second order kinetic and Freundlich isotherm model. Moreover, MB molecules were adsorbed by diffusion on the outer surface, diffusion on the inner surface, and adsorption on the inner surface of NaP1 zeolite. And, during the external diffusion, electrostatic attraction and hydrogen bonding created. Al and Si were extracted from RM to prepare NaP1 zeolite with excellent adsorption properties. This result provides an important example for the development of the potential value of RM.  相似文献   

8.
Methane (CH4), as the vital energy resource and industrial chemicals, is highly flammable and explosive for concentrations above the explosive limit, triggering potential risks to personal and production safety. Therefore, exploiting smart gas sensors for real-time monitoring of CH4 becomes extremely important. Herein, the Pt-Pd nanoalloy functionalized mesoporous SnO2 microspheres (Pt-Pd/SnO2) were synthesized, which show uniform diameter (≈500 nm), high surface area (40.9–56.5 m2 g−1), and large mesopore size (8.8–15.8 nm). The highly dispersed Pt-Pd nanoalloys are confined in the mesopores of SnO2, causing the generation ofoxygen defects and increasing the carrier concentration of sensitive materials. The representative Pt1-Pd4/SnO2 exhibits superior CH4 sensing performance with ultrahigh response (Ra/Rg = 21.33 to 3000 ppm), fast response/recovery speed (4/9 s), as well as outstanding stability. Spectroscopic analyses imply that such an excellent CH4 sensing process involves the fast conversion of CH4 into formic acid and CO intermediates, and finally into CO2. Density functional theory (DFT) calculations reveal that the attractive covalent bonding interaction and rapid electron transfer between the Pt-Pd nanoalloys and SnO2 support, dramatically promote the orbital hybridization of Pd4 sites and adsorbed CH4 molecules, enhancing the catalytic activation of CH4 over the sensing layer.  相似文献   

9.
Due to the relatively high capacity and lower cost, transition metal sulfides (TMS) as anode show promising potential in sodium-ion batteries (SIBs). Herein, a binary metal sulfide hybrid consisting of carbon encapsulated CoS/Cu2S nanocages (CoS/Cu2S@C-NC) is constructed. The interlocked hetero-architecture filled with conductive carbon accelerates the Na+/e transfer, thus leading to improved electrochemical kinetics. Also the protective carbon layer can provide better volume accommondation upon charging/discharging. As a result, the battery with CoS/Cu2S@C-NC as anode displays a high capacity of 435.3 mAh g−1 after 1000 cycles at 2.0 A g−1 (≈3.4 C). Under a higher rate of 10.0 A g−1 (≈17 C), a capacity of as high as 347.2 mAh g−1 is still remained after long 2300 cycles. The capacity decay per cycle is only 0.017%. The battery also exhibits a better temperature tolerance at 50 and −5 °C. A low internal impedance analyzed by X-ray diffraction patterns and galvanostatic intermittent titration technique, narrow band gap, and high density of states obtained by first-principle calculations of the binary sulfides, ensure the rapid Na+/e transport. The long-cycling-life SIB using binary metal sulfide hybrid nanocages as anode shows promising applications in versatile electronic devices.  相似文献   

10.
Using interfacial reaction systems for biphasic catalytic reactions is attracting more and more attention due to their simple reaction process and low environmental pollution. Yolk–shell structured materials have broad applications in biomedicine, catalysis, and environmental remediation owing to their open channels and large space for guest molecules. Conventional methods to obtain yolk–shell mesoporous materials rely on costly and complex hard‐template strategies. In this study, a mild and convenient nonsacrificial self‐template strategy is developed to construct yolk–shell magnetic periodic mesoporous organosilica (YS‐mPMO) particles by using the unique swelling–deswelling property of low‐crosslinking density resorcinol formaldehyde (RF). The obtained YS‐mPMO microspheres possess an amphiphilic outer shell, high surface area (393 m2 g?1), uniform mesopores (2.58 nm), a tunable middle hollow space (50–156 nm), and high superparamagnetism (34.4–37.1 emu g?1). By tuning the synthesis conditions, heterojunction structured yolk–shell Fe3O4@RF@void@PMO particles with different morphologies can be produced. Owing to the amphipathy of PMO framworks, the YS‐mPMO particles show great emulsion stabilization ability and recyclability under a magnetic field. YS‐mPMO microspheres with immobilized Au nanoparticles (≈3 nm) act as both solid emulsifier for dispersing styrene (St) in water and interface catalysts for selective conversion of St into styrene oxide with a high selectivity of 86%, and yields of over 97%.  相似文献   

11.
《Advanced Powder Technology》2021,32(9):3372-3387
Cubical-shaped zeolite A was synthesized from the Linz-Donawitz (LD) process slag of the Steel Industry, utilizing conventional fusion-assisted hydrothermal treatment. Morphological and Physico-chemical characterizations were performed by various characterization techniques. A weight ratio of 1:1.2 (LD-slag: NaOH) was maintained during fusion, which provides a better binding effect with better mechanical stability to the zeolite framework. Fe3+ adsorption studies were performed at 273, 298, 303, and 308 K, respectively, within the range of 10–40 mg L−1 Fe3+ ion concentration for kinetic and isotherm studies. A maximum adsorption capacity of 27.55 mg g−1 was obtained at a 1.4 g L−1 adsorbent dosage, with 99.99% Fe3+ ion removal. Moreover, the Fe3+ adsorption study obeyed the pseudo-second-order kinetic model, whereas multistage diffusion controlled the adsorption process. Langmuir isotherm model best fitted the equilibrium data suggesting the highly negative charge over the adsorbent surface played a vital role in the electrostatic attraction of Fe3+ ions. Isomorphic replacement of silicon by aluminum ion imparted a highly negative charge over the zeolite surface in the primary structure unit. For real-life sample drinking water, the Fe3+ ion removal efficiency increases to 97.7%.  相似文献   

12.
Exploring anode materials with fast, safe, and stable Li-(de)intercalation is of great significance for developing next-generation lithium-ion batteries. Monoclinic H-type niobium pentoxide possesses outstanding intrinsic fast Li-(de)intercalation kinetics, high specific capacity, and safety; however, its practical rate capability and cycling stability are still limited, ascribed to the asynchronism of phase change throughout the crystals. Herein this problem is addressed by homogenizing the electron and Li-ion conductivity surrounding the crystals. An amorphous N-doped carbon layer is introduced on the micrometer single-crystal H-Nb2O5 particle to optimize the homogeneity of electron and Li-ion transport. As a result, the as-prepared H-Nb2O5 exhibits high reversible capacity (>250 mAh g−1 at 50 mA g−1), unprecedented high-rate performance (≈120 mAh g−1 at 16.0 A g−1) and excellent cycling stability (≈170 mAh g−1 at 2.0 A g−1 after 1000 cycles), which is by far the highest performance among the H-Nb2O5 materials. The inherent principle is further confirmed via operando transmission electron microscopy and X-ray diffraction. A novel insight into the further development of electrode materials forlithium-ion batteries is thus provided.  相似文献   

13.
The high conductivities and good mechanical properties of hydrogel electrolyte films are critical for energy storage devices with high flexibility, fast redox kinetics, and long life. Herein, a low water content (6.63 wt%) hydrogel film is prepared, and a favorable environment is created, with an electrochemical stability window of 2.26 V and a high ionic conductivity of 2.6 mS cm−1. The hydrogel film exhibits good folding ability, low in-plane swelling, and anti-freezing abilities. These properties are benefitted by immobilizing free water molecules on the abundant oxygenic groups of polymer fibers in the hydrogel film, offering a unique 3D channel to allow Li+ to quickly transport along the polymer network. Therefore, the hydrogel film-based all-in-one flexible cell exhibits stable cycling performance with a retention of 81.8% of the initial capacity after 500 cycles at room temperature and 66.2% of capacity retention at −30 °C. Furthermore, the full cell with high cathode loading (≈21 mg cm−2) exhibits a high areal capacity of 2.5 mAh cm−2 (≈119 mAh g−1). The overall merits of flexible all-in-one quasi-solid-state batteries demonstrate high potential to be used for power wearable electronics.  相似文献   

14.
Selenium (Se)‐based rechargeable aluminum batteries (RABs), known as aluminum–selenium (Al–Se) batteries, are an appealing new battery design that holds great promise for addressing the low‐capacity problem of current RAB technology. However, their applications are hindered by mediocre high‐rate capacity (≈100 mAh g?1 at 0.5 A g?1) and insufficient cycling life (50 cycles). Herein, the synthesis of mesoporous carbon fibers (MCFs) by coating mesoporous carbon with short‐length mesopores and tunable mesopore sizes (2.7 to 8.9 nm) coaxially on carbon nanotubes (CNT) is reported. When compositing MCFs with Se for Al–Se batteries, a positive correlation between mesopore size and electrolyte ion diffusivity is observed, however when pore size is increased to 8.9 nm, large voids are created at the interface of CNT core and mesoporous carbon shell, leading to decreased electrode conductivity. The trade‐off between ion diffusivity and interfacial connectivity/conductivity determines MCF with pore size of 7.1 nm as the best host material for Al–Se batteries. The composite cathode delivers high specific capacities (366 and 230 mAh g?1 at 0.5 and 1 A g?1), good rate performance, and excellent cycling stability (152 mAh g?1 after 500 cycles at 2 A g?1), superior over previously reported Se cathodes and other cathodes for RABs.  相似文献   

15.
《Advanced Powder Technology》2020,31(10):4301-4309
The agriculture shell wastes were carbothermally converted to magnetic activated carbon by a microwave-assisted decoration of iron oxide nanoparticles onto the shell surface. The influence of ternary catalytic mixtures, including zinc, iron II and III chlorides on the cationic dye adsorption efficiency was addressed by the composite impregnations onto the almond or walnut shell powders, explored to the carbonization. The efficiency was maximized by determination the proportions of used salts. The best results were obtained with loading FeCl3 onto the walnut shell in which the proportion of salt was 50%. Although the load of magnetic particles onto the adsorbent normally lead to decrease in efficiency, the prepared powder exhibited the appropriate performance above 99%. It should be point out that the dye adsorption efficiency of magnetic activated carbons fabricated by carbothermal functionalization was 7–10% higher than those produced in the nitrogen atmosphere. The adsorbent displayed the nano-porous structure with average pore diameter about 2 nm, providing a surface area around 1000 m2·g−1 for the removal of dye in a dynamic system. The maximum adsorption capacity was determined to be 130 mg·g−1 in the neutral condition.  相似文献   

16.
Magnetic hollow structures with microporous shell and highly dispersed active cores (Fe/Fe3C nanoparticles) are rationally designed and fabricated by solution‐phase switchable transport of active iron species combined with a solid‐state thermolysis technique, thus allowing selective encapsulation of functional Fe/Fe3C nanoparticles in the interior cavity. These engineered functional materials show high loading (≈54 wt%) of Fe, excellent chromium removal capability (100 mg g?1), fast adsorption rate (8766 mL mg?1 h?1), and easy magnetic separation property (63.25 emu g?1). During the adsorption process, the internal highly dispersed Fe/Fe3C nanoparticles supply a driving force for facilitating CrVI diffusion inward, thus improving the adsorption rate and the adsorption capacity. At the same time, the external microporous carbon shell can also efficiently trap guest CrVI ions and protect Fe/Fe3C nanoparticles from corrosion and subsequent leaching problems.  相似文献   

17.
It is essential but still challenging to design and construct inexpensive, highly active bifunctional oxygen electrocatalysts for the development of high power density zinc–air batteries (ZABs). Herein, a CoFe-S@3D-S-NCNT electrocatalyst with a 3D hierarchical structure of carbon nanotubes growing on leaf-like carbon microplates is designed and prepared through chemical vapour deposition pyrolysis of CoFe-MOF and subsequent hydrothermal sulfurization. Its 3D hierarchical structure shows excellent hydrophobicity, which facilitates the diffusion of oxygen and thus accelerates the oxygen reduction reaction (ORR) kinetic process. Alloying and sulfurization strategies obviously enrich the catalytic species in the catalyst, including cobalt or cobalt ferroalloy sulfides, their heterojunction, core–shell structure, and S, N-doped carbon, which simultaneously improve the ORR/OER catalytic activity with a small potential gap (ΔE = 0.71 V). Benefiting from these characteristics, the corresponding liquid ZABs show high peak power density (223 mW cm−2), superior specific capacity (815 mA h gZn−1), and excellent stability at 5 mA cm−2 for ≈900 h. The quasi-solid-state ZABs also exhibit a very high peak power density of 490 mW cm−2 and an excellent voltage round-trip efficiency of more than 64%. This work highlights that simultaneous composition optimization and microstructure design of catalysts can effectively improve the performance of ZABs.  相似文献   

18.
Flexible energy storage device is one of the most critical components as power source for wearable electronics. The emergence of MXenes, a growing family of 2D nanomaterials, has demonstrated a brand-new possibility for flexible energy storage. However, the fabrication of MXene films with satisfactory mechanical, electrical, and electrochemical reliabilities remains challenging due to the weak interlayer interactions and self-restacking of MXene sheets. Sequential bridging of polydopamine/polyethyleneimine-functionalized (PDA/PEI)-coated MXene sheets to induce synergistically covalent and hydrogen binding connections of MXene-based films is demonstrated here. By interrupting self-hydrogen bonding and ππ stacking interactions, the introduction of long-chain PEI can not only inhibit the massive aggregation of PDA, but also improve the continuity of the interconnection network of PDA/PEI between MXene layers. Hence, the as-prepared MXene/PDA/PEI composite film displays high mechanical strength (≈366 MPa) which achieves 12-fold improvement compared with pure MXene film, as well as superior energy storage capability (≈454 F g−1 at 5 mV s−1) and rate performance of ≈48% at 10 000 mV s−1. This modulation of inserted polymer between MXene layers can provide an avenue for assembling high performance MXene films, and can even be extended to the fabrication of other 2D platelets for varied applications.  相似文献   

19.
Arsenic (As) in drinking water and its related toxicology are serious concerns nowadays. Development of better techniques related to removal of As from drinking water is an urgent need. Layered double hydroxide (LDH) or hydrotalcite-like compound with the general formula [M1−x 2+ M x 3+ (OH)2] x+ A x·nH2O can be considered as a good adsorbent for the removal of toxic As from water. Due to large surface area and high anion exchange capacity of LDH, the compound may be a good adsorbent for the removal of As from contaminated water. In this study, the removal of As in aqueous solution by adsorption method based on the calcination–rehydration reaction was investigated in batch experiment at (30 ± 1)°C. Results showed the removal of 99.99% As from a solution of 0.1 ppm of As; the adsorbent required at saturation was 0.10 g/20 ml As solution with 90 min of exposure at (30 ± 1)°C. Factors like pH, adsorbent dose and shaking time influenced the rate of As removal. Experiment showed that the adsorption process follows the Freundlich-type adsorption isotherm. The explanation of adsorption phenomenon is supported by X-ray diffraction pattern.  相似文献   

20.
1D core–shell magnetic materials with mesopores in shell are highly desired for biocatalysis, magnetic bioseparation, and bioenrichment and biosensing because of their unique microstructure and morphology. In this study, 1D magnetic mesoporous silica nanochains (Fe3O4@nSiO2@mSiO2 nanochain, Magn‐MSNCs named as FDUcs‐17C) are facilely synthesized via a novel magnetic‐field‐guided interface coassembly approach in two steps. Fe3O4 particles are coated with nonporous silica in a magnetic field to form 1D Fe3O4@nSiO2 nanochains. A further interface coassembly of cetyltrimethylammonium bromide and silica source in water/n‐hexane biliquid system leads to 1D Magn‐MSNCs with core–shell–shell structure, uniform diameter (≈310 nm), large and perpendicular mesopores (7.3 nm), high surface area (317 m2 g?1), and high magnetization (34.9 emu g?1). Under a rotating magnetic field, the nanochains with loaded zoledronate (a medication for treating bone diseases) in the mesopores, show an interesting suppression effect of osteoclasts differentiation, due to their 1D nanostructure that provides a shearing force in dynamic magnetic field to induce sufficient and effective reactions in cells. Moreover, by loading Au nanoparticles in the mesopores, the 1D Fe3O4@nSiO2@mSiO2‐Au nanochains can service as a catalytically active magnetic nanostirrer for hydrogenation of 4‐nitrophenol with high catalytic performance and good magnetic recyclability.  相似文献   

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