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•Zn-based MOF-74 was assembled and controlled as nanoshuttles morphology.•Core-shell Au@Pd functional nanoparticles were encapsulated into MOF-74.•Pt nanoparticles were deposited on ...the surface of MOF-74 and Au@Pd@MOF-74.•The composite catalysts exhibit selective catalytic effectiveness for CO2 conversion.
The Zn-based metal-organic framework (MOF) catalysts MOF-74, Au@Pd@MOF-74, Pt/MOF-74, and Pt/Au@Pd@MOF-74, were assembled. Core-shell Au@Pd, in which Au nanoparticles (NPs) serve as the core for the epitaxial growth of Pd shells, was encapsulated into MOF-74 nanoshuttles to control the MOF-74 morphology and impart NP functionality. Pt NPs were loaded onto the MOF-74 surface. Pt/MOF-74 catalyzed CO2 conversion at 99.7% CO selectivity in the reverse water-gas shift (RWGS) reaction, and Au@Pd@MOF-74 photocatalyzed CO2 with 100% CO selectivity. Importantly, the catalyst Pt/Au@Pd@MOF-74, not only catalyzed the conversion of CO2 to CO in RWGS with 99.6% selectivity, but also photocatalyzed CO2 to CH4 at low concentration (800 ppm).
Nanofiltration (NF) is considered a promising candidate to improve the separation efficiency in water desalination, and the membranes with incomparable water permeance and great selectivity are ...urgently requried to reduce the energy consumption. Iron oxohydroxides (FeOOH) nanorods, goethite (α-FeOOH) with a diameter of 30–40 nm and length of about 340 nm, were synthesized and deposited on PES microfiltration (MF) membrane with the pore size of 0.1 μm by the assistance of vacuum filtration. Then a high flux NF membrane intercalated by well-dispersed FeOOH nanorods was fabricated using piperazine (PIP) and trimesoyl chloride (TMC) as monomers. The influence of FeOOH deposition on the surface properties and the nanofiltration performance of the fabricated membranes was studied. XPS, SEM, TEM, AFM, water contact angle (WCA) and NF measurements were utilized to investigate membrane performance. The optimum membranes showed a high water permeability (34.1 L·m−2·h−1·bar−1), high rejection for Na2SO4 (95.0%) and good ion selectivity towards Cl−/SO42− (23.9). Furthermore, the optimized NF membranes are acid-stable to some extent, and showed good stability in long-term NF operations. This work presents a facile and low-cost strategy for constructing high performance NF membranes.
•FeOOH nanorods were synthesized via hydrothermal method.•FeOOH-interlayed thin-film NF membranes were fabricated by interfacial polymerization.•The prepared NF membrane showed a pure water flux of 34.1 L·m−2·h−1·bar−1 and Na2SO4 rejection of 95.0%.
High water permeability and good separation property are greatly desired in water production due to energy concerns. To explore nanofiltration (NF) membrane with high permeability for cations ...separation, a positively charged NF membrane was fabricated via interfacial polymerization using polyethersulfone (PES) three-channel capillary ultrafiltration (UF) membrane as substrate, polyethyleneimine (PEI) as the aqueous precursor. The NF membrane preparation conditions were optimized. To enhance the permeability of the prepared NF membrane, modified hydroxyl contained multi-walled carbon nanotubes (MWCNTs-OH), grafting with piperazine (PIP), were utilized. The resultant NF membrane showed increased water flux from 20.8L·m−2·h−1 to 56.1L·m−2·h−1 at 4bar after adding 0.01wt% modified MWCNTs-OH in aqueous solution. Interestingly, MgCl2 rejection of the membrane also increased from 94.2% to 96.9%. The positively charged NF membrane exhibited above 97% rejection for divalent cations (Mg2+ and Ca2+) and low rejection (<70%) for monovalent cations (Na+ and Li+), and it also showed long durability and good separation for Mg2+ and Li+ when the membrane was used to separate mixed salts solution simulated the composition of salt lake brine. The fabricated membrane would have potential for effective water softening and for reclamation of lithium from brine or seawater with high Mg2+/Li+ ratio.
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•MWCNTs-OH was modified by grafting with PIP.•Tri-pores positively charged NF membrane was fabricated with modified MWCNTs in aqueous solution.•The prepared NF membrane showed highly improved permeability and good separation for Mg2+ and Li+.
In this work, three modified multiwalled carbon nanotubes (MWCNTs) with carboxyl (MWCNT-COOH), hydroxyl (MWCNT-OH) and amino groups (MWCNT-NH), respectively, were added into the aqueous phase ...containing piperazine (PIP) to fabricate the nanocomposite nanofiltration (NF) membranes via interfacial polymerization. The influences of functional groups of MWCNTs on the performance of modified NF membrane were investigated. The MWCNTs were characterized by TEM, FT-IR and TGA; meanwhile, the properties of the membranes were evaluated by XPS, TEM, AFM and contact angle. The XPS results proved the successful incorporation of MWCNT in the active layer of modified NF membrane. When the MWCNT concentration is 0.01% (w/v), all the nanocomposite membranes possessed the optimal separation properties, among which the membrane incorporated with MWCNT-OH demonstrated the highest water flux of 41.4 L·m–2·h–1 and the Na2SO4 rejection of 97.6% whereas the one with MWCNT-COOH had the relative lowest rejection of 96.6%. Furthermore, the increased hydrophilicity of functional groups in modified MWCNTs resulted in different nodular surface morphologies, thicknesses and hydrophilicities of the nanocomposite membranes. All the membranes possessed a molecular weight cutoff (MWCO) within 300 Da and good operation stability.
The dye-water treatment using UF membrane is still a challenge. In the present study, the optimized PAN-ETA ultrafiltration membrane was hydrolyzed and subsequently characterized by SEM, IR, CA, XPS, ...NMR, mechanic measurement, etc. The obtained membrane (H-PAN-ETA) was used for dye removal and it showed both an excellent anti-dye fouling and a good rejection property for anionic dyes. I.e. 96% rejection for methyl blue (MB), 99% for congo red (CR), 94% for acid fuchsin (AF) with no sign of contamination by dye. The flux of H-PAN-ETA membrane maintained at 50–53 L m−2⋅ h−1 during a 10-h filtration, which is higher than that of tight UF membranes reported. Meanwhile, H-PAN-ETA membrane was able to selectively remove cationic dyes, such as methylene blue (MEB), rhodamine B (RB) and, crystal violet (CV), or the mixture of anionic dye/cationic dye by adsorption process. Its adsorption capacity remained unchanged after 20 cycles. Finally, the immobile electrical double layer (EDL) theory combined with electrostatic force was introduced to explain the separation mechanism of charged UF membrane, which is helpful to instruct the preparation of UF membrane for dye removal.
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•H-PAN-ETA membrane shows strong repulsion to anionic dye and affinity to cationic dye.•H-PAN-ETA membrane shows a high flux, high rejection and anti-dye fouling to methyl blue.•H-PAN-ETA membrane can separate anionic dye/cationic dye mixture by selective adsorption.•Rejection mechanism of H-PAN-ETA membrane was explained by the immobile EDL theory.
Conversion‐alloying type anode materials like metal sulfides draw great attention due to their considerable theoretical capacity for sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs). ...However, poor conductivity, severe volume change, and harmful aggregation of the material during charge/discharge lead to unsatisfying electrochemical performance. Herein, a facile and green strategy for yolk–shell structure based on the principle of metal evaporation is proposed. SnS2 nanoparticle is encapsulated in nitrogen‐doped hollow carbon nanobox (SnS2@C). The carbon nanoboxes accommodate the volume change and aggregation of SnS2 during cycling, and form 3D continuous conductive carbon matrix by close contact. The well‐designed structure benefits greatly in conductivity and structural stability of the material. As expected, SnS2@C exhibits considerable capacity, superior cycling stability, and excellent rate capability in both SIBs and PIBs. Additionally, in situ Raman technology is unprecedentedly conducted to investigate the phase evolution of polysulfides. This work provides an avenue for facilely constructing stable and high‐capacity metal dichalcogenide based anodes materials with optimized structure engineering. The proposed in‐depth electrochemical measurements coupled with in situ and ex situ characterizations will provide fundamental understandings for the storage mechanism of metal dichalcogenides.
The successful structural engineering of SnS2@C gives effective accommodation to the volume change of SnS2 during charge/discharge as well as the enhancement of the conductivity. Owing to the positive effect of the N‐doped carbon nanoboxes with interior void space, the as‐prepared SnS2@C anode with satisfying capacity exhibits excellent cycling stability and superior rate capability.
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•In situ catalytic growth graphene on the surface of nano-Si is developed.•Folded multi-layers graphene could be uniform grown on the nano Si particles.•Strong connection between ...graphene and nano-Si is maintained during cycling.•Graphene@Si exhibits excellent cycling performance and high rate capability.
Silicon (Si) has been considered as the next generation ideal anode material for lithium-ion batteries because of its highest theoretical capacity (4200 mAh·g−1) and affluent reserves in nature. However, the severe volume expansion and unstable solid electrolyte interface (SEI) film of Si electrode during lithiation/delithiation, as well as the poor electron conductivity have seriously restricted its commercial application. In this work, in situ catalytic growth graphene on the surface of nano-Si (Si@Graphene) composite is successfully developed through a novel electroless deposition approach with Ni as the catalyst. The as-prepared Si@Graphene composite exhibits excellent cycling stability and rate capability, which retains a reversible discharge capacity up to 1909 mAh g−1 after 100 cycles at 0.2 A g−1, and is able to deliver a discharge capacity of 975 mAh g−1 even at a high current density of 52 A g−1. The results indicate that a folded multi-layers graphene could be uniformly grown on the nano-Si particles by permeating the Ni catalytic layer using the triethylene glycol (triglycol) as carbon source. The folded multi-layers graphene could maintain the framework structure of the composite during the electrochemical cycling for its excellent mechanical performance and outstanding flexibility, which could relieve volume expansion/shrinkage of Si during repeated Li+ intercalation/extraction. Moreover, the strong connection between the graphene and nano-Si in three dimensional also could provide abundant transport pathway for the electron transportation to the surface of Si particles. The most important thing is that the multi-layer graphene could protect the nano-Si particles from being directly exposed to the electrolyte, which is beneficial for maintaining the stability of SEI films.
Hypochloric acid (HClO) is mainly distributed in acidic lysosomes of phagocytes and closely associated with numerous physiological and pathological processes, especially inflammatory response. ...Fluorescent probe has become an important tool for imaging HClO in lysosomes, but suffered from interference from autofluorescence in vivo, phototoxicity to biosamples and photobleaching phenomenon due to their short-wavelength excitation and emission. Unfortunately, up to now, no near-infrared (NIR) lysosome-targetable fluorescent probe has been reported for imaging HClO. In this paper, a near-infrared fluorescent probe Lyso-NIR-HClO for imaging lysosomal HClO was reported for the first time. Lyso-NIR-HClO based on Si-rhodamine is consisted of a morpholine unit as a lysosome-targetable group and a HClO-mediated cyclization reaction site as a response group, which was applied for highly selective and sensitive detection and imaging for endogenous and exogenous HClO in lysosomes, with a linear range from 5.0 × 10−8 to 1.0 × 10−5 M and a detection limit of 2.0 × 10−8 M in vitro. Attributed to NIR emission and excellent photostability of Si-rhodamine, Lyso-NIR-HClO exhibits excellent performances in vivo, such as low interference from intracellular autofluorescence, stable and persistent fluorescence signal and good tissue penetration, which are in favor of accurate, time-lapse and long-term imaging for HClO. Finally, we applied the probe Lyso-NIR-HClO to visualize endogenous HClO during lysosome-involved inflammatory response including bacteria-infected cells and inflamed mouse model with satisfactory results. The above results proved that Lyso-NIR-HClO would be a potentially useful tool for the study of biological functions and pathological roles of HClO in lysosomes, especially role of lysosome in the inflammatory response.
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•A near-infrared fluorescent probe for imaging lysosomal HClO, Lyso-NIR-HClO, was reported for the first time.•Lyso-NIR-HClO exhibited excellent performances in vivo based on NIR emission and excellent photostability of Si-rhodamine.•Lyso-NIR-HClO was successfully applied to visualize endogenous HClO during lysosome-involved inflammatory response.
Accurate control of a quantum system is a fundamental requirement in many areas of modern science ranging from quantum information processing to high-precision measurements. A significantly important ...goal in quantum control is preparing a desired state as fast as possible, with sufficiently high fidelity allowed by available resources and experimental constraints. Stimulated Raman adiabatic passage (STIRAP) is a robust way to realize high-fidelity state transfer but it requires a sufficiently long operation time to satisfy the adiabatic criteria. Here we theoretically propose and then experimentally demonstrate a shortcut-to-adiabatic protocol to speed-up the STIRAP. By modifying the shapes of the Raman pulses, we experimentally realize a fast and high-fidelity stimulated Raman shortcut-to-adiabatic passage that is robust against control parameter variations. The all-optical, robust and fast protocol demonstrated here provides an efficient and practical way to control quantum systems.
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