Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other field...Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.展开更多
All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical applic...All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.展开更多
Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(...Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.展开更多
The utilization of cellulose nanocrystals(CNCs),a renewable and eco-friendly nanomaterial,has emerged as the favored option for sustainable fillers.This paper presents diverse methods for CNCs preparation,including ac...The utilization of cellulose nanocrystals(CNCs),a renewable and eco-friendly nanomaterial,has emerged as the favored option for sustainable fillers.This paper presents diverse methods for CNCs preparation,including acid hydrolysis,oxidation,mechanical method,enzymatic hydrolysis,solvent method and hybrid approach.The strategies for modifying CNCs can be summarized as encompassing physical adsorption through non-covalent bond interactions and chemical modifications via covalent bonding.Moreover,the applications of CNCs in sensing systems,electronic skin devices,packaging materials,electronics industries,stabilizers and cosmetics are discussed with a particular emphasis on their contribution to enhancing polymer matrix properties.Lastly,future prospects for the advancement of CNCs are explored with a focus on its potential impact on sustainability efforts.展开更多
Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradati...Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradation in practical applications,which is a common issue for halide perovskites.Here,we reported the heat-resistant FAPbBr_(3)NCs prepared by a ligand-engineered room-temperature synthesis strategy.An aromatic amine,specificallyβ-phenylethylamine(PEA)or 3-fluorophenylethylamine(3-F-PEA),was incoporated as the short-chain ligand to expedite the crystallization rate and control the size distribution of FAPbBr_(3)NCs.Employing this ligand engineering approach,we synthesized high quality FAPbBr_(3)NCs with uniform grain size and reduced long-chain alkyl ligands,resulting in substantially suppressed thermal quenching and enhanced carrier transportation in the perovskite NCs films.Most notably,more than 90%of the room temperature PL intensity in the 3-F-PEA modified FAPbBr_(3)NCs film was preserved at 380 K.Consequently,we fabricated ultra-pure green EL devices with a room temperature external quantum efficiency(EQE)as high as 21.9%at the luminance of above 1,000 cd m^(-2),and demonstrated less than 10%loss in EQE at 343 K.This study introduces a novel room temperature method to synthesize efficient FAPbBr_(3)NCs with exceptional thermal stability,paving the way for advanced optoelectronic device applications.展开更多
Lead halide perovskite(LHP)nanocrystals(NCs)suffer from poor stability against environmental factors(heat,moisture,oxygen,etc.),which seriously hinders their practical application.Constructing a core-shell structure c...Lead halide perovskite(LHP)nanocrystals(NCs)suffer from poor stability against environmental factors(heat,moisture,oxygen,etc.),which seriously hinders their practical application.Constructing a core-shell structure could be an effective approach to improve the stability and optical properties of the LHP NCs.Herein,a novel strategy of water-triggered phase transformation and phospholipid(DSPE)micelle encapsulation is proposed,generating highly luminescent water-dispersed CsPbBr_(3)@CsPb_(2)Br5@DSPE core-shell-shell nanocrystals.The epitaxial growth of the CsPb_(2)Br5 shell is induced by the in-situ reconstruc-tion of the CsPbBr_(3) surface by water erosion,and the lattice mismatch with the CsPbBr_(3) core is small(3.8%).The further amphipathic phospholipid encapsulation guarantees their excellent water dispersity and stability.Revealed by the femtosecond transient absorption spectroscopy,the dense CsPb_(2)Br5@DSPE shell effectively passivates the surface of the CsPbBr_(3) core,thus improving its stability and luminescence performance.The resulting CsPbBr_(3)@CsPb_(2)Br5@DSPE nanoparticles exhibit excellent performance as fluo-rescent probes for bioimaging,aqueous inks for high-resolution pattering,and light conversion layers for LEDs,demonstrating their promising potential in multiple applications.展开更多
Composites derived from metal-organic frameworks(MOFs)show promise as catalysts for the photocat-alytic reduction of CO_(2).However,their potential is hindered by constraints such as limited light absorp-tion and slug...Composites derived from metal-organic frameworks(MOFs)show promise as catalysts for the photocat-alytic reduction of CO_(2).However,their potential is hindered by constraints such as limited light absorp-tion and sluggish electron transfer and separation,impacting the overall efficiency of the photocatalytic process.In this study,TiO_(2)nanocrystals,modified with Ptx+,underwent laser etching were encapsulated within the traditional MOF-ZIF-8 framework.This enhanced the adsorption capabilities for CO_(2)reactants and solar light,while also facilitating directed electron transfer and the separation of photogenerated charges.The finely-tuned catalyst demonstrates impressive CH_(4) selectivity at 9.5%,with yields of 250.24μmol g^(-1)h^(-1)for CO and 25.43μmol g^(-1)h^(-1)for CH_(4),utilizing water as a hole trap and H^(+)source.This study demonstrates the viability of achieving characteristics related to the separation of photogen-erated charges in TiO_(2)nanocrystals through laser etching and MOF composite catalysts.It offers novel perspectives for designing MOF-based catalysts with enhanced performance in artificial photosynthesis.展开更多
Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs ...Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs has been controlled by tuning the oleic acid(OA)/oleylamine(OLA)feed ratio in conventional injection-based synthesis.Although the emerging bimolecular nucleophilic substitution(S_(N)2)-based heatup synthesis enables the production of high-quality and monodisperse PNCs,achieving dimensional tunability by altering the OA/OLA feed ratio remains challenging in this approach.Herein,we present an integrated strategy for controlling the dimensionality and surface properties of CsPbI_(3)-PNCs based on the S_(N)2-based heat-up method.Our approach focuses on the regulation of OLA protonation and oleylammonium(OAM^(+))latticeforming behavior.Using chemical analysis,we identify the protonation routes of OLA in S_(N)2 reactions and demonstrate that adjusting the acid–base and S_(N)2 reactions involving OA and OLA can reduce OLA protonation and the subsequent formation of OAM^(+).Furthermore,by enhancing the competitive lattice-forming behavior of Cs^(+)over OAM+,we suppress excessive surface termination by OAM^(+).These approaches achieve dimensional tunability between two-dimensional(2D)nanoplatelets and three-dimensional(3D)nanocubes in the S_(N)2-based heat-up synthesis,along with subsequent spectral control of optical features.To independently optimize their surface passivation,we employ a post-synthetic passivation(PSP)strategy using OAM^(+)–I−pairs,which increases the photoluminescence quantum yield of PNCs from 71.9%to 81.7%by reducing surface defects.展开更多
Titanium dioxide(TiO_(2))nanocrystals have garnered significant interest in nanofluid research field due to their controllable morphology,eco-friendly nature,and superior lubrication properties.However,the long-term d...Titanium dioxide(TiO_(2))nanocrystals have garnered significant interest in nanofluid research field due to their controllable morphology,eco-friendly nature,and superior lubrication properties.However,the long-term dispersion stability of TiO_(2) nanocrystals remains a significant challenge.This study demonstrates that the morphology,{001}facet exposure,and consequent surface modifier adsorption density of TiO_(2) nanocrystals are synergistically controlled by modulating the facetspecific adsorption of oleic acid(OA),oleylamine(OM),and dioleamide during solvothermal synthesis.This control mechanism directly governs both dispersion stability and interfacial lubrication behavior.Crucially,the high-density modifier layer establishes a steric stabilization barrier,which ensures colloidal stability.The optimized TiO_(2) nanocrystals(TiO_(2)-OAOM)exhibit colloidal stability for over 5 months and enhance the antiwear properties of the base oil by 10-fold.Furthermore,synergistic interactions between TiO_(2)-OAOM and zinc dialkyl dithiophosphate(ZDDP)are confirmed in multiple friction pairs.These interactions promote the hardness and wear resistance of the tribo-film,thereby improving lubrication performance and suppressing metal transfer.This study provides a novel strategy for the co-optimization of dispersion stability and tribological properties of nanocrystals through surface engineering,offering novel insights into the design of nanofluids and a potent solution for lubrication challenges on lowhardness metals.展开更多
Trivalent europium is a well-known phosphorescent probe widely used in lighting devices and displays,bioassay markers,and anti-counterfeiting phosphors.Double halide perovskite nanocrystals(DHP NCs)have emerged in rec...Trivalent europium is a well-known phosphorescent probe widely used in lighting devices and displays,bioassay markers,and anti-counterfeiting phosphors.Double halide perovskite nanocrystals(DHP NCs)have emerged in recent years as attractive host lattices for various luminescent lanthanide dopants owing to the diverse range of trivalent substitutional sites.However,the effect of the DHP NC composition on the Eu^(3+)emission properties has not been systematically investigated.In this work,we prepared a series of DHP NCs containing Eu^(3+)by employing a modified colloidal hot injection procedure.The nanocrystals exhibit finely tunable Eu^(3+)5D0-^(7)F_(J)emission peaks,owing to the different dependence of the electric and magnetic dipole f-f transitions on the coordination symmetry of Eu^(3+).A variation in the values of the Eu^(3+)asymmetry factor,defined as^(7)F_(2)/^(7)F_(1)peak intensity ratio,between 1.0 and 2.5 was observed for different NC compositions,compared to ca.5 for Eu^(3+)in an aqueous solution.The asymmetry factor was also found to be dependent on the Eu^(3+)doping concentration for a given DHP NC host lattice.The sensitivity of the relative intensities of Eu^(3+)emission peaks on the DHP NC composition,together with the dual emission of these NCs,is promising for various anti-counterfeiting applications.展开更多
Recent breakthroughs in hot carrier(HC)cooling dynamics within halide perovskite nanocrystals(NCs)have positioned them as promising candidates for next-generation optoelectronic applications.Therefore,it is of great i...Recent breakthroughs in hot carrier(HC)cooling dynamics within halide perovskite nanocrystals(NCs)have positioned them as promising candidates for next-generation optoelectronic applications.Therefore,it is of great importance to systematically summarize advances in understanding and controlling HC relaxation mechanisms.Here,we offer an overview of advances in the understanding of the HC cooling process in perovskite NCs,with a focus on influences of excitation energy,excitation intensity,composition,size,dimensionality,doping,and core-shell structure on the HC cooling times.Finally,we propose suggestions for future investigations into the HC cooling process in perovskite NCs.展开更多
Nitric oxide(NO),which generally originates from vehicle exhaust and industrial flue gases,is one of the most serious air pollutants.In this case,the electrochemical NO reduction reaction(NORR)not only removes the atm...Nitric oxide(NO),which generally originates from vehicle exhaust and industrial flue gases,is one of the most serious air pollutants.In this case,the electrochemical NO reduction reaction(NORR)not only removes the atmospheric pollutant NO but also produces valuable ammonia(NH_(3)).Hence,through the synthesis and modification of Fe_(3)C nanocrystal cata-lysts,the as-obtained optimal sample of Fe_(3)C/C-900 was adopted as the NORR catalyst at ambient conditions.As a result,the Fe_(3)C/C-900 catalyst showed an NH_(3)Faraday efficiency of 76.5%and an NH_(3)yield rate of 177.5μmol·h^(-1)·cm^(-2)at the working potentials of-0.8 and-1.2 V versus reversible hydrogen electrode(vs.RHE),respectively.And it delivered a stable NORR activity during the electrolysis.Moreover,we attribute the high NORR properties of Fe_(3)C/C-900 to two aspects:one is the enhanced intrinsic activity of Fe_(3)C nanocrystals,including the lowering of the energy barrier of rate-limiting step(*NOH→*N)and the inhibition of hydrogen evolution;on the other hand,the favorable dispersion of active components,the effective adsorption of gaseous NO,and the release of liquid NH_(3)products facilitated by the porous carbon substrate.展开更多
In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering （S...In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering （SAXS）, transmission electron microscopy （TEM） along with other physical techniques. The study includes growth kinetics of gold nanocrystals formed by the reduction of HAuCl4 by tetrakis（hydroxymethyl） phosphonium chloride in aqueous solution, of CdSe nanocrystals formed by the reaction of cadmium stearate and selenium under solvothermal conditions, and of ZnO nanorods formed by the reaction of zinc acetate with sodium hydroxide under solvothermal conditions in the absence and presence of capping agents. The growth of gold nanocrystals does not follow the diffusion-limited Ostwald ripening, and instead follows a Sigmoidal rate curve. The heat change associated with the growth determined by isothermal titration calorimetry is about 10 kcal·mol^-1 per I nm increase in the diameter of the nanocrystals. In the case of CdSe nanocrystals also, the growth mechanism deviates from diffusion-limited growth and follows a combined model containing both diffusion and surface reaction terms. Our study of the growth kinetics of uncapped and poly（vinyl pyrollidone） （PVP）-capped ZnO nanorods has yielded interesting insights. We observe small nanocrystals next to the ZnO nanorods after a lapse of time in addition to periodic focusing and defocusing of the width of the length distribution. These observations lend support to the diffusion-limited growth model for the growth of uncapped ZnO nanorods. Accordingly, the time dependence on the length of uncapped nanorods follows the L3 law as required for diffusion-limited Ostwald ripening. The PVP-capped nanorods, however, show a time dependence, which is best described by a combination of diffusion （L^3） and surface reaction （L^2） terms.展开更多
Tin oxide nanociystals with diameters smaller than 10 nm were synthesized using Na2SnO3 and CO2 as reactants and cetyltrimethylammonium bromide（CTAB） as stabilizer under mild conditions.As a mild acidic gas,CO2 is f...Tin oxide nanociystals with diameters smaller than 10 nm were synthesized using Na2SnO3 and CO2 as reactants and cetyltrimethylammonium bromide（CTAB） as stabilizer under mild conditions.As a mild acidic gas,CO2 is favorable for the accurate adjustment of pH value of Na2SnO3 solution.Stannate salt is stable,cheap and easy in operation.The effects of Na2SnO3concentration,CTAB concentration,aging temperature,and aging time on the nanociystals were studied.It was found that,with the increasing Na2SnO3 concentration,aging temperature and aging time,SnO2 nanociystals size decreases.The formation of SnO2nanociystals can be interpreted by electrostatic-interaction mechanism.SnO2 nanociystals show high photocatalytic activities in the degradation of Rhodamine B solution.The catalytic activity of small nanocrystals is higher than that of large ones.展开更多
Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcinatio...Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated.The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity.The experimental results show that concentration quenching occurs when the mole fraction of Tm3+is above 0.2%.The optimal Tm3+and Yb3+doped molar fractions are 0.2%and 2%,respectively.The strong blue(490 nm)and the weak red(653 nm)emissions from the prepared nanocrystals were observed under 980 nm laser excitation,and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3+,respectively.Power-dependent study reveals that the 1G4 levels of Tm3+can be populated by three-step energy transfer process.The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature.The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH-groups and the enlarged nanoerystal size.展开更多
A novel nanoadsorbent for the removal of heavy metal ions is reported.Cotton was first hydrolyzed to obtain cellulose nanocrystals（CNCs）.CNCs were then chemically modified with succinic anhydride to obtain SCNCs.The...A novel nanoadsorbent for the removal of heavy metal ions is reported.Cotton was first hydrolyzed to obtain cellulose nanocrystals（CNCs）.CNCs were then chemically modified with succinic anhydride to obtain SCNCs.The sodic nanoadsorbent（NaSCNCs） was further prepared by treatment of SCNCs with saturated NaHCO 3 aqueous solution.Batch experiments were carried out with SCNCs and NaSCNCs for the removal of Pb 2＋ and Cd 2＋.The effects of contact time,pH,initial adsorption concentration,coexisting ions and the regeneration performance were investigated.Kinetic studies showed that the adsorption equilibrium time of Pb 2＋ and Cd 2＋ was reached within 150 min on SCNCs and 5 min on NaSCNCs.The adsorption capacities of Pb 2＋ and Cd 2＋ on SCNCs and NaSCNCs increased with increasing pH.The adsorption isotherm was well fitted by the Langmuir model.The maximum adsorption capacities of SCNCs and NaSCNCs for Pb 2＋ and Cd 2＋ were 367.6 mg/g,259.7 mg/g and 465.1 mg/g,344.8 mg/g,respectively.SCNCs and NaSCNCs showed high selectivity and interference resistance from coexisting ions for the adsorption of Pb 2＋.NaSCNCs could be efficiently regenerated with a mild saturated NaCl solution with no loss of capacity after two recycles.The adsorption mechanisms of SCNCs and NaSCNCs were discussed.展开更多
AIM： To improve the absorption and bioavailability of baicalin using a nanocrystal （or nanosuspension） drug delivery system. METHODS： A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to ...AIM： To improve the absorption and bioavailability of baicalin using a nanocrystal （or nanosuspension） drug delivery system. METHODS： A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to prepare baicalin-nanocrystal dried powders, and the physicochemical properties of baicalin-nanocrystals were characterized by scanning electron microscopy, photon correlation spectroscopy, powder X-ray diffraction, physical stability, and solubility experiments. Furthermore, in situ intestine single-pass perfusion experiments and pharmacokinetics in rats were performed to make a comparison between the microcrystals of baicalin and pure baicalin in their absorption properties and bioavailability in vivo. RESULTS： The mean particle size of baicalin-nanocrystals was 236 nm, with a polydispersity index of 0.173, and a zeta potential value of-34.8 mV, which provided a guarantee for the stability of the reconstituted nanosuspension. X-Ray diffraction results indicated that the crystallinity of baicalin was decreased through the ultrasonic-homogenization process. Physical stability experiments showed that the prepared baicalin-nanocrystals were sufficiently stable. It was shown that the solubility of baicalin in the form of nanocrystals, at 495 ug·mL-1, was much higher than the baicalin-microcrystals and the physical mixture （135 and 86.4 ug·mL- 1, respectively）. In situ intestine perfusion experiments demonstrated a clear advantage in the dissolution and absorption characteristics for baicalin-nanocrystals compared to the other formulations. In addition, after oral administration to rats, the particle size decrease from the micron to nanometer range exhibited much higher in vivo bioavailability （with the AUC（0-t） value of 206.96 ± 21.23 and 127.95 ± 14.41 mg·L-1·h-1, respectively）. CONCLUSION： The nanocrystal drug delivery system using an ultrasonic-homogenization-fluid bed drying process is able to improve the absorption and in vivo bioavailability of baicalin, compared with pure baicalin coarse powder and micronized baicalin.展开更多
Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidatio...Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.展开更多
Nanocrystals,a carrier-free colloidal delivery system in nano-sized range,is an interesting approach for poorly soluble drugs.Nanocrystals provide special features including enhancement of saturation solubility,dissol...Nanocrystals,a carrier-free colloidal delivery system in nano-sized range,is an interesting approach for poorly soluble drugs.Nanocrystals provide special features including enhancement of saturation solubility,dissolution velocity and adhesiveness to surface/cell membranes.Several strategies are applied for nanocrystals production including precipitation,milling,high pressure homogenization and combination methods such as Nano-Edge^(TM),SmartCrystal and Precipitation-lyophilization-homogenization(PLH)technology.For oral administration,many publications reported useful advantages of nanocrystals to improve in vivo performances i.e.pharmacokinetics,pharmacodynamics,safety and targeted delivery which were discussed in this review.Additionally,transformation of nanocrystals to final formulations and future trends of nanocrystals were also described.展开更多
Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suita...Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suitable for intranasal administration to treat Parkinson’s disease(PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of-23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%,which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells.Moreover, PA-NCs conferred desirable protective effect against MPP+-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PANCs is a promising treatment strategy for PD.展开更多
基金supported by the National Key R&D Program of China(Grant No.2023YFA1406200)the National Natural Science Foundation of China(No.12274177 and 12304261)the China Postdoctoral Science Foundation(No.2024M751076)。
文摘Luminescent metal-organic frameworks(MOFs)have garnered significant attention due to their structural tunability and potential applications in solid-state lighting,bioimaging,sensing,anticounterfeiting,and other fields.Nevertheless,due to the tendency of1,4-benzenedicarboxylic acid(BDC)to rotate within the framework,MOFs composed of it exhibit significant non-radiative energy dissipation and thus impair the emissive properties.In this study,efficient luminescence of MIL-140A nanocrystals(NCs)with BDC rotors as ligands is achieved by pressure treatment strategy.Pressure treatment effectively modulates the pore structure of the framework,enhancing the interactions between the N,N-dimethylformamide vip molecules and the BDC ligands.The enhanced host-vip interaction contributes to the structural rigidity of the MOF,thereby suppressing the rotation-induced excited-state energy loss.As a result,the pressure-treated MIL-140A NCs displayed bright blue-light emission,with the photoluminescence quantum yield increasing from an initial 6.8%to 69.2%.This study developed an effective strategy to improve the luminescence performance of rotor ligand MOFs,offers a new avenue for the rational design and synthesis of MOFs with superior luminescent properties.
基金supported by the National Natural Science Foundation of China(No.52062019)the Natural Science Research Project of Higher Education Institutions in Jiangsu Province,China(No.24KJA430013)the Natural Science Foundation of Jiangsu Province for Youths,China(No.BK20230662)。
文摘All-inorganic perovskite CsPbX_(3)(X=Cl,Br,I)nanocrystals(NCs)have emerged as promising candidates for light-emitting diode(LED)displays due to their outstanding photophysical properties.However,their practical application remains hindered by poor stability and the inherent toxicity of Pb2+.In this study,we present a two-step heating method to synthesize CsPb_(1-x)Zn_(x)Br_(3)NCs with enhanced optoelectronic performance and uniform dispersion.The optimized Zn^(2+)-doped NCs achieve a photoluminescence quantum yield(PLQY)of 86%,with a reduction in lattice spacing from 0.384 to 0.365 nm,attributed to increased perovskite lattice formation energy and effective surface passivation.To further improve stability,a silica(SiO_(2))shell is introduced via surface modification with(3-aminopropyl)triethoxysilane(APTES),forming CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)core–shell NCs.At an optimal APTES/B-site metal ion molar ratio of 1.8,the PLQY increases to 96%.The SiO2encapsulation significantly enhances environmental stability,with coated NCs retaining 43%of their initial photoluminescence(PL)intensity after immersion in water for 36 h,compared to only 5%for uncoated NCs.Furthermore,after ethanol treatment for 210 min,the coated NCs retain 39%of their initial PL intensity,while the uncoated counterparts retain merely7%.The enhanced stability and luminescence performance of CsPb_(0.7)Zn_(0.3)Br_(3)@SiO_(2)NCs make them highly promising for LED applications.White light-emitting diodes(WLEDs)fabricated using these NCs exhibit a color rendering index(CRI)of 78.2,a correlated color temperature(CCT)of 5470 K,and a luminous efficiency(LE)of 54.2 lm/W,demonstrating significant potential for next-generation display and lighting technologies.
基金Project supported by the National Natural Science Foundation of China(61805134,11974229,22303044)Fundamental Research Program of Shanxi Province(202203021221121)+3 种基金China Postdoctoral Science Foundation(2022M711898)Natural Science Fo undation of Shandong Province(ZR2023QB135)Postdoctoral Innovation Project of Shandong Province(SDCX-ZG-202201004)Graduate Innovation Project in Shanxi Province(2024KY450)。
文摘Owing to their unique optical properties and nontoxicity,lead-free halide double perovskite nanocrystals are of interest for widespread applications.Herein,the colloid synthesis and photoluminescenc e property of Ag^(+)-Eu^(3+)codoped Cs_(2)NaInCl_(6)nanocrystals were investigated.The pe rovskite nanocrystals exhibit a broad warm-white photo luminescence with correlated color temperature(CCT)of 3447 K and color rendering index(CRI)of 90.2,and the means of codoping would improve its optical performance.A fast energy transfer and a long-lived self-trapped excitons state are unveiled by the femtosecond transient absorption spectra.The fast energy transfer from the self-trapped excitons of host nanocrystals to the Eu^(3+)ions is helpful to achieve a broad photoluminescence,and the quantum yield of Cs_(2)NaInCl_(6):0.05Ag^(+)-Eu^(3+)anocrystals can be enha nced to 69.5%.There is a large exciton binding energy and strong electron-phonon interaction in the codoped perovskite nanocrystals.The efficient and excellent air-stable double perovskite nanocrystals would be considered as a single-component phosphor for warm-white lighting.
基金National Natural Science Foundation of China(grant number 52341301)the Basic Scientific Research Project of Liaoning Provincial Department of Education,China(grant number LJKMZ20220767)Outstanding Young Talent Projects of Shenyang University of Chemical Technology,China(grant number 2019YQ003).
文摘The utilization of cellulose nanocrystals(CNCs),a renewable and eco-friendly nanomaterial,has emerged as the favored option for sustainable fillers.This paper presents diverse methods for CNCs preparation,including acid hydrolysis,oxidation,mechanical method,enzymatic hydrolysis,solvent method and hybrid approach.The strategies for modifying CNCs can be summarized as encompassing physical adsorption through non-covalent bond interactions and chemical modifications via covalent bonding.Moreover,the applications of CNCs in sensing systems,electronic skin devices,packaging materials,electronics industries,stabilizers and cosmetics are discussed with a particular emphasis on their contribution to enhancing polymer matrix properties.Lastly,future prospects for the advancement of CNCs are explored with a focus on its potential impact on sustainability efforts.
基金support from the National Key Research and Development Program of China(2022YFE0206000)the National Natural Science Foundation of China(U2001219,51973064)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2023B1515040003,2024A1515010262)the Natural Science Foundation of Guangdong Province(2023B1212060003)the Open Project Program of Wuhan National Laboratory for Optoelectronics(NO.2021WNLOKF014)the State Key Lab of Luminescent Materials and Devices,South China University of Technology(Skllmd-2023-05).
文摘Formamidinium lead bromide(FAPbBr_(3))perovskite nanocrystals(NCs)are promising for display and lighting due to their ultra-pure green emission.However,the thermal quenching will exacerbate their performance degradation in practical applications,which is a common issue for halide perovskites.Here,we reported the heat-resistant FAPbBr_(3)NCs prepared by a ligand-engineered room-temperature synthesis strategy.An aromatic amine,specificallyβ-phenylethylamine(PEA)or 3-fluorophenylethylamine(3-F-PEA),was incoporated as the short-chain ligand to expedite the crystallization rate and control the size distribution of FAPbBr_(3)NCs.Employing this ligand engineering approach,we synthesized high quality FAPbBr_(3)NCs with uniform grain size and reduced long-chain alkyl ligands,resulting in substantially suppressed thermal quenching and enhanced carrier transportation in the perovskite NCs films.Most notably,more than 90%of the room temperature PL intensity in the 3-F-PEA modified FAPbBr_(3)NCs film was preserved at 380 K.Consequently,we fabricated ultra-pure green EL devices with a room temperature external quantum efficiency(EQE)as high as 21.9%at the luminance of above 1,000 cd m^(-2),and demonstrated less than 10%loss in EQE at 343 K.This study introduces a novel room temperature method to synthesize efficient FAPbBr_(3)NCs with exceptional thermal stability,paving the way for advanced optoelectronic device applications.
基金support from the National Natural Science Foundation of China(Nos.U1905213 and 52303132)the Natural Science Foundation of Hubei Province(No.2024AFB142)the Scientific Research Fund Project of Wuhan Institute of Technology(No.K2023109).
文摘Lead halide perovskite(LHP)nanocrystals(NCs)suffer from poor stability against environmental factors(heat,moisture,oxygen,etc.),which seriously hinders their practical application.Constructing a core-shell structure could be an effective approach to improve the stability and optical properties of the LHP NCs.Herein,a novel strategy of water-triggered phase transformation and phospholipid(DSPE)micelle encapsulation is proposed,generating highly luminescent water-dispersed CsPbBr_(3)@CsPb_(2)Br5@DSPE core-shell-shell nanocrystals.The epitaxial growth of the CsPb_(2)Br5 shell is induced by the in-situ reconstruc-tion of the CsPbBr_(3) surface by water erosion,and the lattice mismatch with the CsPbBr_(3) core is small(3.8%).The further amphipathic phospholipid encapsulation guarantees their excellent water dispersity and stability.Revealed by the femtosecond transient absorption spectroscopy,the dense CsPb_(2)Br5@DSPE shell effectively passivates the surface of the CsPbBr_(3) core,thus improving its stability and luminescence performance.The resulting CsPbBr_(3)@CsPb_(2)Br5@DSPE nanoparticles exhibit excellent performance as fluo-rescent probes for bioimaging,aqueous inks for high-resolution pattering,and light conversion layers for LEDs,demonstrating their promising potential in multiple applications.
文摘Composites derived from metal-organic frameworks(MOFs)show promise as catalysts for the photocat-alytic reduction of CO_(2).However,their potential is hindered by constraints such as limited light absorp-tion and sluggish electron transfer and separation,impacting the overall efficiency of the photocatalytic process.In this study,TiO_(2)nanocrystals,modified with Ptx+,underwent laser etching were encapsulated within the traditional MOF-ZIF-8 framework.This enhanced the adsorption capabilities for CO_(2)reactants and solar light,while also facilitating directed electron transfer and the separation of photogenerated charges.The finely-tuned catalyst demonstrates impressive CH_(4) selectivity at 9.5%,with yields of 250.24μmol g^(-1)h^(-1)for CO and 25.43μmol g^(-1)h^(-1)for CH_(4),utilizing water as a hole trap and H^(+)source.This study demonstrates the viability of achieving characteristics related to the separation of photogen-erated charges in TiO_(2)nanocrystals through laser etching and MOF composite catalysts.It offers novel perspectives for designing MOF-based catalysts with enhanced performance in artificial photosynthesis.
基金supported by the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(Nos.RS-2023-00207907 and RS-2024-00444458).
文摘Lead-halide perovskite nanocrystals(PNCs)exhibit exceptional optical properties with size-and dimensiontunable optical bandgaps,making them promising for diverse optoelectronic applications.The dimensionality of PNCs has been controlled by tuning the oleic acid(OA)/oleylamine(OLA)feed ratio in conventional injection-based synthesis.Although the emerging bimolecular nucleophilic substitution(S_(N)2)-based heatup synthesis enables the production of high-quality and monodisperse PNCs,achieving dimensional tunability by altering the OA/OLA feed ratio remains challenging in this approach.Herein,we present an integrated strategy for controlling the dimensionality and surface properties of CsPbI_(3)-PNCs based on the S_(N)2-based heat-up method.Our approach focuses on the regulation of OLA protonation and oleylammonium(OAM^(+))latticeforming behavior.Using chemical analysis,we identify the protonation routes of OLA in S_(N)2 reactions and demonstrate that adjusting the acid–base and S_(N)2 reactions involving OA and OLA can reduce OLA protonation and the subsequent formation of OAM^(+).Furthermore,by enhancing the competitive lattice-forming behavior of Cs^(+)over OAM+,we suppress excessive surface termination by OAM^(+).These approaches achieve dimensional tunability between two-dimensional(2D)nanoplatelets and three-dimensional(3D)nanocubes in the S_(N)2-based heat-up synthesis,along with subsequent spectral control of optical features.To independently optimize their surface passivation,we employ a post-synthetic passivation(PSP)strategy using OAM^(+)–I−pairs,which increases the photoluminescence quantum yield of PNCs from 71.9%to 81.7%by reducing surface defects.
基金supported by Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0470202)International Partnership Program of Chinese Academy of Sciences(No.307GJHZ2022034GC)Key Project of the Henan Province Science and Technology Research and Development Joint Funds(No.235101610007).
文摘Titanium dioxide(TiO_(2))nanocrystals have garnered significant interest in nanofluid research field due to their controllable morphology,eco-friendly nature,and superior lubrication properties.However,the long-term dispersion stability of TiO_(2) nanocrystals remains a significant challenge.This study demonstrates that the morphology,{001}facet exposure,and consequent surface modifier adsorption density of TiO_(2) nanocrystals are synergistically controlled by modulating the facetspecific adsorption of oleic acid(OA),oleylamine(OM),and dioleamide during solvothermal synthesis.This control mechanism directly governs both dispersion stability and interfacial lubrication behavior.Crucially,the high-density modifier layer establishes a steric stabilization barrier,which ensures colloidal stability.The optimized TiO_(2) nanocrystals(TiO_(2)-OAOM)exhibit colloidal stability for over 5 months and enhance the antiwear properties of the base oil by 10-fold.Furthermore,synergistic interactions between TiO_(2)-OAOM and zinc dialkyl dithiophosphate(ZDDP)are confirmed in multiple friction pairs.These interactions promote the hardness and wear resistance of the tribo-film,thereby improving lubrication performance and suppressing metal transfer.This study provides a novel strategy for the co-optimization of dispersion stability and tribological properties of nanocrystals through surface engineering,offering novel insights into the design of nanofluids and a potent solution for lubrication challenges on lowhardness metals.
基金financially supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)(Nos.RGPIN-2020-04958 and STPGP 521224-2018)Scholars at Risk(SAR)Network for a research fellowship(SAR-Ukraine Fellowship)
文摘Trivalent europium is a well-known phosphorescent probe widely used in lighting devices and displays,bioassay markers,and anti-counterfeiting phosphors.Double halide perovskite nanocrystals(DHP NCs)have emerged in recent years as attractive host lattices for various luminescent lanthanide dopants owing to the diverse range of trivalent substitutional sites.However,the effect of the DHP NC composition on the Eu^(3+)emission properties has not been systematically investigated.In this work,we prepared a series of DHP NCs containing Eu^(3+)by employing a modified colloidal hot injection procedure.The nanocrystals exhibit finely tunable Eu^(3+)5D0-^(7)F_(J)emission peaks,owing to the different dependence of the electric and magnetic dipole f-f transitions on the coordination symmetry of Eu^(3+).A variation in the values of the Eu^(3+)asymmetry factor,defined as^(7)F_(2)/^(7)F_(1)peak intensity ratio,between 1.0 and 2.5 was observed for different NC compositions,compared to ca.5 for Eu^(3+)in an aqueous solution.The asymmetry factor was also found to be dependent on the Eu^(3+)doping concentration for a given DHP NC host lattice.The sensitivity of the relative intensities of Eu^(3+)emission peaks on the DHP NC composition,together with the dual emission of these NCs,is promising for various anti-counterfeiting applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.62475169 and 62174079)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2025A1515011195)+2 种基金the Guangdong Provincial Quantum Science Strategic Initiative(Grant No.GDZX2404006)the Shenzhen Science and Technology Program(Grant Nos.JCYJ20240813143212016 and JCYJ20231122200233001)the Post-doctoral Later-stage Foundation Project of Shenzhen Polytechnic University(Grant No.6024271003K)。
文摘Recent breakthroughs in hot carrier(HC)cooling dynamics within halide perovskite nanocrystals(NCs)have positioned them as promising candidates for next-generation optoelectronic applications.Therefore,it is of great importance to systematically summarize advances in understanding and controlling HC relaxation mechanisms.Here,we offer an overview of advances in the understanding of the HC cooling process in perovskite NCs,with a focus on influences of excitation energy,excitation intensity,composition,size,dimensionality,doping,and core-shell structure on the HC cooling times.Finally,we propose suggestions for future investigations into the HC cooling process in perovskite NCs.
基金supported by the Guangxi Natural Science Fund for Distinguished Young Scholars(2024GXNSFFA010008)Shenzhen Science and Technology Program(JCYJ20230807112503008).
文摘Nitric oxide(NO),which generally originates from vehicle exhaust and industrial flue gases,is one of the most serious air pollutants.In this case,the electrochemical NO reduction reaction(NORR)not only removes the atmospheric pollutant NO but also produces valuable ammonia(NH_(3)).Hence,through the synthesis and modification of Fe_(3)C nanocrystal cata-lysts,the as-obtained optimal sample of Fe_(3)C/C-900 was adopted as the NORR catalyst at ambient conditions.As a result,the Fe_(3)C/C-900 catalyst showed an NH_(3)Faraday efficiency of 76.5%and an NH_(3)yield rate of 177.5μmol·h^(-1)·cm^(-2)at the working potentials of-0.8 and-1.2 V versus reversible hydrogen electrode(vs.RHE),respectively.And it delivered a stable NORR activity during the electrolysis.Moreover,we attribute the high NORR properties of Fe_(3)C/C-900 to two aspects:one is the enhanced intrinsic activity of Fe_(3)C nanocrystals,including the lowering of the energy barrier of rate-limiting step(*NOH→*N)and the inhibition of hydrogen evolution;on the other hand,the favorable dispersion of active components,the effective adsorption of gaseous NO,and the release of liquid NH_(3)products facilitated by the porous carbon substrate.
文摘In this article, we report the results of our detailed investigations of the growth kinetics of zero-dimensional nanocrystals as well as one-dimensional nanorods by the combined use of small angel X-ray scattering （SAXS）, transmission electron microscopy （TEM） along with other physical techniques. The study includes growth kinetics of gold nanocrystals formed by the reduction of HAuCl4 by tetrakis（hydroxymethyl） phosphonium chloride in aqueous solution, of CdSe nanocrystals formed by the reaction of cadmium stearate and selenium under solvothermal conditions, and of ZnO nanorods formed by the reaction of zinc acetate with sodium hydroxide under solvothermal conditions in the absence and presence of capping agents. The growth of gold nanocrystals does not follow the diffusion-limited Ostwald ripening, and instead follows a Sigmoidal rate curve. The heat change associated with the growth determined by isothermal titration calorimetry is about 10 kcal·mol^-1 per I nm increase in the diameter of the nanocrystals. In the case of CdSe nanocrystals also, the growth mechanism deviates from diffusion-limited growth and follows a combined model containing both diffusion and surface reaction terms. Our study of the growth kinetics of uncapped and poly（vinyl pyrollidone） （PVP）-capped ZnO nanorods has yielded interesting insights. We observe small nanocrystals next to the ZnO nanorods after a lapse of time in addition to periodic focusing and defocusing of the width of the length distribution. These observations lend support to the diffusion-limited growth model for the growth of uncapped ZnO nanorods. Accordingly, the time dependence on the length of uncapped nanorods follows the L3 law as required for diffusion-limited Ostwald ripening. The PVP-capped nanorods, however, show a time dependence, which is best described by a combination of diffusion （L^3） and surface reaction （L^2） terms.
基金Projects (20676016,21076024) supported by the National Natural Science Foundation of China
文摘Tin oxide nanociystals with diameters smaller than 10 nm were synthesized using Na2SnO3 and CO2 as reactants and cetyltrimethylammonium bromide（CTAB） as stabilizer under mild conditions.As a mild acidic gas,CO2 is favorable for the accurate adjustment of pH value of Na2SnO3 solution.Stannate salt is stable,cheap and easy in operation.The effects of Na2SnO3concentration,CTAB concentration,aging temperature,and aging time on the nanociystals were studied.It was found that,with the increasing Na2SnO3 concentration,aging temperature and aging time,SnO2 nanociystals size decreases.The formation of SnO2nanociystals can be interpreted by electrostatic-interaction mechanism.SnO2 nanociystals show high photocatalytic activities in the degradation of Rhodamine B solution.The catalytic activity of small nanocrystals is higher than that of large ones.
基金Foundation item:Projects(10704090,10774140,11047147)supported by the National Natural Science Foundation of ChinaProjects(KJ090514,KJTD201016)supported by the Natural Science Foundation of Chongqing Municipal Education Commission,China
文摘Lutetium oxide nanocrystals codoped with Tm3+and Yb3+were synthesized by the reverse-like co-precipitation method,using ammonium hydrogen carbonate as precipitant.Effects of the Tm3+,Yb3+molar fractions and calcination temperature on the structural and upconversion luminescent properties of the Lu2O3 nanocrystals were investigated.The XRD results show that all the prepared nanocrystals can be readily indexed to pure cubic phase of Lu2O3 and indicate good crystallinity.The experimental results show that concentration quenching occurs when the mole fraction of Tm3+is above 0.2%.The optimal Tm3+and Yb3+doped molar fractions are 0.2%and 2%,respectively.The strong blue(490 nm)and the weak red(653 nm)emissions from the prepared nanocrystals were observed under 980 nm laser excitation,and attributed to the 1G4→3H6 and IG4→3F4 transitions of Tm3+,respectively.Power-dependent study reveals that the 1G4 levels of Tm3+can be populated by three-step energy transfer process.The upconversion emission intensities of 490 nm and 653 nm increase gradually with the increase of calcination temperature.The enhancement of the upconversion luminescence is suggested to be the consequence of reducing number of OH-groups and the enlarged nanoerystal size.
基金supported by the National Basic Research Program (973) of China (No. 2011CB933700) of Ministry of Science and Technology of China
文摘A novel nanoadsorbent for the removal of heavy metal ions is reported.Cotton was first hydrolyzed to obtain cellulose nanocrystals（CNCs）.CNCs were then chemically modified with succinic anhydride to obtain SCNCs.The sodic nanoadsorbent（NaSCNCs） was further prepared by treatment of SCNCs with saturated NaHCO 3 aqueous solution.Batch experiments were carried out with SCNCs and NaSCNCs for the removal of Pb 2＋ and Cd 2＋.The effects of contact time,pH,initial adsorption concentration,coexisting ions and the regeneration performance were investigated.Kinetic studies showed that the adsorption equilibrium time of Pb 2＋ and Cd 2＋ was reached within 150 min on SCNCs and 5 min on NaSCNCs.The adsorption capacities of Pb 2＋ and Cd 2＋ on SCNCs and NaSCNCs increased with increasing pH.The adsorption isotherm was well fitted by the Langmuir model.The maximum adsorption capacities of SCNCs and NaSCNCs for Pb 2＋ and Cd 2＋ were 367.6 mg/g,259.7 mg/g and 465.1 mg/g,344.8 mg/g,respectively.SCNCs and NaSCNCs showed high selectivity and interference resistance from coexisting ions for the adsorption of Pb 2＋.NaSCNCs could be efficiently regenerated with a mild saturated NaCl solution with no loss of capacity after two recycles.The adsorption mechanisms of SCNCs and NaSCNCs were discussed.
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(Nos.20101561,NCET-11-0114)the Beijing Natural Science Foundation(No.7122176)
文摘AIM： To improve the absorption and bioavailability of baicalin using a nanocrystal （or nanosuspension） drug delivery system. METHODS： A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to prepare baicalin-nanocrystal dried powders, and the physicochemical properties of baicalin-nanocrystals were characterized by scanning electron microscopy, photon correlation spectroscopy, powder X-ray diffraction, physical stability, and solubility experiments. Furthermore, in situ intestine single-pass perfusion experiments and pharmacokinetics in rats were performed to make a comparison between the microcrystals of baicalin and pure baicalin in their absorption properties and bioavailability in vivo. RESULTS： The mean particle size of baicalin-nanocrystals was 236 nm, with a polydispersity index of 0.173, and a zeta potential value of-34.8 mV, which provided a guarantee for the stability of the reconstituted nanosuspension. X-Ray diffraction results indicated that the crystallinity of baicalin was decreased through the ultrasonic-homogenization process. Physical stability experiments showed that the prepared baicalin-nanocrystals were sufficiently stable. It was shown that the solubility of baicalin in the form of nanocrystals, at 495 ug·mL-1, was much higher than the baicalin-microcrystals and the physical mixture （135 and 86.4 ug·mL- 1, respectively）. In situ intestine perfusion experiments demonstrated a clear advantage in the dissolution and absorption characteristics for baicalin-nanocrystals compared to the other formulations. In addition, after oral administration to rats, the particle size decrease from the micron to nanometer range exhibited much higher in vivo bioavailability （with the AUC（0-t） value of 206.96 ± 21.23 and 127.95 ± 14.41 mg·L-1·h-1, respectively）. CONCLUSION： The nanocrystal drug delivery system using an ultrasonic-homogenization-fluid bed drying process is able to improve the absorption and in vivo bioavailability of baicalin, compared with pure baicalin coarse powder and micronized baicalin.
基金financially supported by the National Natural Science Foundation of China(No.22008135)the China Postdoctoral Science Foundation(No.2020M670345)。
文摘Today,nanocrystals enclosed by high-index facets(HIFs)are attracting widely attentions of researchers due to their tremendous potential in the field of catalysis,especially in electrocatalysis,such as electro-oxidation of small organic molecule(such as formic acid,methanol,and ethanol),oxygen reduction reaction(ORR),hydrogen evolution reaction(HER),as well as the oxygen evolution reaction(OER).However,the practical applications of nanocrystals enclosed by HIFs still face many limitations in preparations of advanced electrocatalysts,including preparation strategy,limited life-time and stability.The development of advanced electrocatalysts enclosed with HIFs is crucial for solving these problems if the large-scale application of them is to be realized.Herein,we firstly detailedly demonstrate the identification methods of nanocrystals enclosed by HIFs,and then preparation strategies are elaborated in detail in this review.Current advanced nanocrystals enclosed by HIFs in electrocatalytic application are also summarized and we present representative achievements to further reveal the relationship of excellent electrocatalytic performance and nanocrystals with HIFs.Finally,we predict the remaining challenges and present our perspectives with regards of design strategies of improving electrocatalytic performance of Ptbased catalysts in the future.
基金the Thailand Research Fund through Thai Basic Research Grant(BRG5680020 to V.B.J.)the Royal Golden Jubilee Ph.D.Program and Mahidol。
文摘Nanocrystals,a carrier-free colloidal delivery system in nano-sized range,is an interesting approach for poorly soluble drugs.Nanocrystals provide special features including enhancement of saturation solubility,dissolution velocity and adhesiveness to surface/cell membranes.Several strategies are applied for nanocrystals production including precipitation,milling,high pressure homogenization and combination methods such as Nano-Edge^(TM),SmartCrystal and Precipitation-lyophilization-homogenization(PLH)technology.For oral administration,many publications reported useful advantages of nanocrystals to improve in vivo performances i.e.pharmacokinetics,pharmacodynamics,safety and targeted delivery which were discussed in this review.Additionally,transformation of nanocrystals to final formulations and future trends of nanocrystals were also described.
基金the Guangdong Provincial Natural Science Foundation of China(2018A030310623)the Guangdong Provincial Medical Scientific Research Foundation of China(A2019027)the Guangzhou Science Technology and Innovation Commission Technology Research Projects(201805010005)。
文摘Paeoniflorin(PA) is an anti-Parkinson Chinese medicine with inferior bioavailability and difficulty in delivery to the brain. This research is to develop an efficacious PA nanocrystal formulation(PA-NCs) that is suitable for intranasal administration to treat Parkinson’s disease(PD). PA-NCs were fabricated through an antisolvent precipitation method using TPGS as the stabilizer. The rod-shaped PA-NCs had particle size of 139.6 ± 1.3 nm and zeta potential of-23.2 ± 0.529 mV. A molecular dynamics simulation indicated that van der Waals forces are the primary drivers of interactions between PA and TPGS. In the ex vivo nasal mucosa permeation assay, the cumulative drug release at 24 h was 87.14% ± 5.34%,which was significantly higher than that of free PA. PA-NCs exhibited substantially improved cellular uptake as well as permeability on Calu-3 cells as compared to PA alone. FRET imaging analysis demonstrated that intact NCs could be internalized into Calu-3 cells.Moreover, PA-NCs conferred desirable protective effect against MPP+-induced SH-SY5Y cellular damage. Pharmacokinetic studies revealed a higher PA concentration in the brain following intranasal delivery of PA-NCs. In summary, the intranasal administration of PANCs is a promising treatment strategy for PD.
