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1.
Chem Commun (Camb) ; 2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32016238

RESUMO

Herein, we successfully regulated phosphorus vacancies in Co0.68Fe0.32P through Ar-plasma treatment. The Ar-plasma treated Co0.68Fe0.32P exhibits a delicate surface state where the surface Co and Fe ions show an unusual electron loss. The unique surface state enhances the oxygen evolving performance of the phosphide.

2.
J Am Chem Soc ; 2020 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-32003216

RESUMO

The combination of ferroelectric-optical properties in halide perovskites has attracted tremendous interests because of its potential for optoelectronic and energy applications. However, very few reports focus on the ferroelectricity of all-inorganic halide perovskites quantum dots. Herein, we report a excellent ferroelectricity in CsPbBr3 quantum dots (QDs) with a saturation polarization of 0.25 µC/cm2. Differential scanning calorimeter (DSC), X-ray diffraction (XRD), transmission electronic microscopy (TEM) revealed that the mechanism of ferroelectric-paraelectric switching of CsPbBr3 QDs can be attributed to the phase transition from cubic phase (Pm¯3 m) to orthorhombic phase (Pna21). In the orthorhombic CsPbBr3, the distortion of octahedral [PbBr6]4- structural units and the off-center Cs+ generated the slightly separated centres of positive charge and negative charge, resulting in the ferroelectric properties. The variable temperature emission spectrum from 328 K to 78 K exhibits green luminescence and the gradually red shift due to the phase transition. This finding opens up a avenue to explore the ferroelectric-optical properties of inorganolead halide perovskites for high-performance multifunctional materials.

3.
Biosens Bioelectron ; 153: 112045, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31989940

RESUMO

Ionic liquid composite electrodes have been widely utilized for the fabrication of electrochemical biosensors. However, the biosensing electrode modified with ionic conducting solids remains unexplored. Herein, we prepared a superionic conducting potassium ferrite (K2Fe4O7) under hydrothermal conditions for modifying glassy carbon electrode (GCE). The modified electrode (K2Fe4O7/GCE) showed an excellent electrocatalytic activity towards the oxidation of dopamine (DA). The oxidation peak currents increased linearly with increasing DA concentrations in the range of 1 µM-140 µM, and the detection limit is 0.22 µM (S/N = 3). The developed DA sensor exhibited not only good selectivity for the determination of DA without interfering from ascorbic acid (AA), uric acid (UA), glucose and inorganic ions, but also good reproducibility and stability. Furthermore, the sensor was applied to determine DA concentration in bovine serum and obtained a satisfied result. This study provides a new approach for developing electrochemical biosensors based on ionic conducting solid materials.

4.
ACS Appl Mater Interfaces ; 12(5): 5999-6006, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31944658

RESUMO

Removal of CH4 and CO2 from C2H2 streams remains challenging in the chemical industry. Herein, a robust three-dimensional metal-organic framework, Cu-CPAH, was designed and synthesized through a hydrothermal method. Cu-CPAH exhibits highly selective C2H2 adsorption capacity with respect to both CH4 and CO2, which is ascribed to the enrichment of active sites in the framework. Dynamic breakthrough results reveal that Cu-CPAH serves as a solid adsorbent for high-efficiency purification of C2H2 from an equal proportion of C2H2/CO2 or C2H2/CO2/CH4 at room temperature. Discrete Fourier transform simulations confirm that various active sites preferentially interact with C2H2 other than CO2 and CH4, signifying for the first time that the imino functional groups in the cage contribute greatly to the preferential affinity to C2H2 over CO2 and CH4.

5.
Langmuir ; 35(47): 15131-15136, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31682456

RESUMO

The synthesis of intermetallic antimonides usually depends on either the high-temperature alloying technique from high-purity metals or the flux method in highly poisonous Pb-melt. In this paper, we introduced a soft-chemical method to synthesize intermetallic antimonides from ternary chalcogenide precursors under an argon atmosphere below 200 °C. Powder X-ray diffraction and compositional analysis clearly indicate that a new phase of the Ag3Sb nanocrystal was synthesized from the Ag3SbS3 precursors. Three types of trialkylphosphines (TAPs) were applied as desulfurization agents, and the transformation mechanism was elucidated. The capability of the desulfurization agent follows the sequence of triphenylphosphine (TPP) > tributylphosphine (TBP) > trioctylphosphine (TOP). Besides, this TAP-driven desulfurization route to synthesize the intermetallic phase could also be possible for AgSbSe2 and Sb2S3. Therefore, this paper provides an efficient and mild technique for the fabrication of intermetallic nanocrystals.

6.
Nanoscale ; 11(45): 21943-21952, 2019 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-31701977

RESUMO

Exploring highly efficient catalysts for the oxygen reduction/evolution reaction (ORR/OER) is very important in rechargeable Zn-air batteries. N-doped carbon coupled with transition metal-based species are among the most promising cathode catalysts for Zn-air batteries. However, the aggregation of metal-based sites during the synthetic/cycling process is a serious drawback of these catalysts. Herein, in situ encapsulation of ultra-small Co/Co4N nanoparticles into N-doping carbon nanotubes (N-CNTs) anchored on reduced GO (Co/Co4N@N-CNTs/rGO) has been achieved through pyrolyzing a core-shell-structured ZIF-8@ZIF-67-modified GO (ZIF-8@ZIF-67/GO) precursor; the nanoparticles have been further applied as a bifunctional catalyst in Zn-air batteries. Benefitting from its uniform dispersion of Co-based particles, close contact of Co/Co4N species and N-CNTs, and high N content, Co/Co4N@N-CNTs/rGO shows outstanding catalytic activity/stability towards ORR and OER. Moreover, Zn volatilization and rGO introduction in Co/Co4N@N-CNTs/rGO can effectively promote the reactions of Zn-air cells. Hence, the Co/Co4N@N-CNTs/rGO-based conventional Zn-air battery exhibits a fantastic specific capacity of 783 mA h gZn-1, a continuous discharge platform over 6 days, a high-power density of ∼200 mW cm-2 and an ultra-long cycling life of 440 h with a small overpotential of ∼0.8 V. Moreover, a flexible Co/Co4N@N-CNTs/rGO-based Zn-air cell was also designed and revealed outstanding mechanical flexibility and good electrochemical performance, which suggests its potential application prospects in wearable electronic devices.

7.
Chem Commun (Camb) ; 55(99): 14918-14921, 2019 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-31769771

RESUMO

A porous NH2-MOF-76(Eu) (MOF 1) with unexpected non-luminescence was designed and synthesized. It exhibits selective fluorescence recovery for sensing dipicolinic acid (DPA), a biomarker of Bacillus anthracis. Moreover, a new europium-based MOF (MOF 2) with evident channel changes was obtained through a single-crystal to single-crystal phase transition.


Assuntos
Bacillus anthracis/isolamento & purificação , Európio/química , Estruturas Metalorgânicas/química , Transição de Fase , Biomarcadores , Cristalização , Cristalografia por Raios X , Luminescência , Ácidos Picolínicos/análise
8.
Chem Commun (Camb) ; 55(67): 9927-9930, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31334708

RESUMO

Tyrosine phosphorylation regulates the upstream signaling pathway but accounts for less than 0.1% of total phosphorylation in human cells. Herein, molecularly imprinted mesoporous materials were first synthesized to recognize the phosphorylated tyrosine residue from other phosphorylated residues.


Assuntos
Epitopos , Impressão Molecular , Nanopartículas/química , Compostos Organofosforados/química , Dióxido de Silício/química , Tirosina/metabolismo , Adsorção , Cinética , Fosfopeptídeos/química , Fosforilação , Porosidade , Titânio/química
9.
Small ; 15(29): e1902047, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31350826
10.
Anal Chem ; 91(16): 10532-10540, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31310105

RESUMO

Traditionally, molecular information on metabolites, lipids, and proteins is collected from separate individual tissue samples using different analytical approaches. Herein a novel strategy to minimize the potential material losses and the mismatch between metabolomics, lipidomics, and proteomics data has been demonstrated based on internal extractive electrospray ionization mass spectrometry (iEESI-MS). Sequential detection of lipids, metabolites, and proteins from the same tissue sample was achieved without sample reloading and hardware alteration to MS instrument by sequentially using extraction solutions with different chemical compositions. With respect to the individual compound class analysis, the sensitivity, specificity, and accuracy obtained with the integrative information on metabolites, lipids, and proteins from 57 samples of 13 patients for lung cancer prediction was substantially improved from 54.0%, 51.0%, and 76.0% to 100.0%, respectively. The established method is featured by low sample consumption (ca. 2.0 mg) and easy operation, which is important to minimize systematic errors in precision molecular diagnosis and systems biology studies.

11.
Angew Chem Int Ed Engl ; 58(34): 11720-11725, 2019 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-31228315

RESUMO

Surface lattice oxygen in transition-metal oxides plays a vital role in catalytic processes. Mastering activation of surface lattice oxygen and identifying the activation mechanism are crucial for the development and design of advanced catalysts. A strategy is now developed to create a spinel Co3 O4 /perovskite La0.3 Sr0.7 CoO3 interface by in situ reconstruction of the surface Sr enrichment region in perovskite LSC to activate surface lattice oxygen. XAS and XPS confirm that the regulated chemical interface optimizes the hybridized orbital between Co 3d and O 2p and triggers more electrons in oxygen site of LSC transferred into lattice of Co3 O4 , leading to more inactive O2- transformed into active O2-x . Furthermore, the activated Co3 O4 /LSC exhibits the best catalytic activities for CO oxidation, oxygen evolution, and oxygen reduction. This work would provide a fundamental understanding to explain the activation mechanism of surface oxygen sites.

12.
Opt Express ; 27(7): 10185-10192, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-31045163

RESUMO

With a potential trap to mimic the finite-size effect, we predict the generation of dark soliton train in a nonresonant polariton condensate excited with the spatially homogeneous continuous wave (cw) field by exploiting the quantum interference in spatial domain. The number of solitons in the train is demonstrated to be controllable on demand in the domain of material parameters. We show that, similar to dark solitons in conservative systems, these nonlinear excitations have infinite lifetime and remain spatially localized even for the periodically oscillating and colliding state of dark soliton train, which do not depend on the parameters of the condensate. Especially, a final state of anti-dark soliton is observed for all kinds of dark soliton trains with the increase of pump power.

13.
Angew Chem Int Ed Engl ; 58(28): 9404-9408, 2019 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-31106512

RESUMO

Atomic metal species-based catalysts (AMCs) show remarkable possibilities in various catalytic reactions. The coordination configuration of the metal atoms has been widely recognized as the determining factor to the electronic structure and the catalytic activity. However, the synergistic effect between the adjacent layers of the multilayered AMCs is always neglected. We reported an atomic Co and Pt co-trapped carbon catalyst, which exhibits a ultrahigh activity for HER in the wide range of pH (η10 =27 and 50 mV in acidic and alkaline media, respectively) with ultralow metal loadings (1.72 and 0.16 wt % for Co and Pt, respectively), which is much superior to the commercial Pt/C. Theoretical analysis reveals that the atomic metals on the inner graphitic layers significantly alter the electronic structure of the outmost layer, thus tailoring the HER activity. This finding arouses a re-thinking of the intrinsic activity origins of AMCs and suggests a new avenue in the structure design of AMCs.

14.
ACS Appl Mater Interfaces ; 11(19): 17459-17466, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31021071

RESUMO

Spinel Co3O4, consisting of two mixed valence states, Co2+ and Co3+, has attracted enormous interest as a promising electrocatalyst for oxygen evolution reaction (OER). Proper control on the relative proportion of Co2+/Co3+ in cobalt oxide can greatly tune the electronic structure and further optimize its catalytic performance. Herein, a hybrid coupling Co3O4 with black phosphorus (Co3O4@BP) is designed as an efficient catalyst for OER. Electron migration from BP to Co3O4 is achieved in Co3O4@BP, owing to the higher Fermi level of BP than that of Co3O4. Efficient electron transfer can not only create massive active sites with abundant Co2+ but also remarkably suppress the deterioration of BP. Particularly, the Co3O4@BP catalyst outperforms the pristine Co3O4 by over four times and is even 20 times higher than that of bare BP at a potential of 1.65 V versus reversible hydrogen electrode. Our finding provides insightful understanding for electronic engineering in Co3O4@BP by balancing advantages and utilizing drawbacks of Co3O4 and BP.

15.
Nanoscale ; 11(14): 6533-6537, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30906939

RESUMO

Quaternary Cd-Cu-Fe-S nanocrystals (NCs) exhibiting a strong size tunable photoluminescence were synthesized for the first time by tuning the reaction temperature from 120 °C to 210 °C. The preparation procedure involved cadmium acetate, copper acetate, iron chloride, and sulfur powder dissolved in oleylamine as precursors. The wavelength of the emission can be tuned from 640 nm to nearly 1000 nm by only changing the size of the as-prepared NCs from 3.0 nm to 15 nm. Interestingly, these NCs possess a relatively high quantum yield of over 57% without coating any wide band-gap shell materials. The study on the optoelectronic properties of Cd-Cu-Fe-S NCs, where an order of photocurrent was enhanced under AM1.5 illumination, demonstrated their suitability as optically active components to fabricate optoelectronic devices.

16.
Angew Chem Int Ed Engl ; 58(16): 5266-5271, 2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30756450

RESUMO

Herein, we present heterogeneous hollow multi-shelled structures (HoMSs) prepared by exploiting the properties of the metal-organic framework (MOFs) casing. Through accurately controlling the transformation of MOF layer into different heterogeneous casings, we can precisely design HoMSs of SnO2 @Fe2 O3 (MOF) and SnO2 @FeOx -C(MOF), which not only retain properties of the original SnO2 -HoMSs, but also structural information from the MOFs. Tested as anode materials in LIBs, SnO2 @Fe2 O3 (MOF)-HoMSs demonstrate superior lithium-storage capacity and cycling stability to the original SnO2 -HoMSs, which can be attributed to the topological features from the MOF casing. Making a sharp contrast to the electrodes of SnO2 @Fe2 O3 (particle)-HoMSs fabricated by hydrothermal method, the capacity retention after 100 cycles for the SnO2 @Fe2 O3 (MOF)-HoMSs is about eight times higher than that of the SnO2 @Fe2 O3 (particle)-HoMS.

17.
Talanta ; 195: 117-126, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30625521

RESUMO

Photoluminescence(PL) nano-biosensors that can be used for accurately and reliably monitoring pH and vitamin hold a great promise in biology and medicine. Herein, a high quantum yield of 16% saccharomyces-derived N-doped carbon dots (s-N-CDs) was synthesized through a simple and one-pot microwave-assisted hydrothermal approach. The produced s-N-CDs are an excellent multi-functional biosensor for the applications of pH sensing and vitamin probing. Fluorescence intensity and fluorescence lifetime dramatically increases with pH decreasing from 14 to 2. Moreover, the fluorescence intensity presents highly reversible abilty from 13 to 2 without any profound attenuation after ten consecutive circles. More importantly, the CDs prepared herein are sound option for assaying cobalamin (VB 12) based fluorescence resonance energy transfer (FRET) with a superior low detection limit of 2.19 µM.


Assuntos
Técnicas Biossensoriais , Concentração de Íons de Hidrogênio , Vitamina B 12/análise , Carbono/química , Etilenodiaminas , Transferência Ressonante de Energia de Fluorescência , Limite de Detecção , Nanopartículas/química , Nitrogênio/química , Saccharomyces , Vitamina B 12/química , Vitaminas
18.
Adv Mater ; 31(38): e1801430, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30430661

RESUMO

Metal oxide hollow structures with large surface area, low density, and high loading capacity have received great attention for energy-related applications. Acting as oxygen-related catalysts, hollow-structured transition metal oxides offer low overpotential, fast reaction rate, and excellent stability. Herein, recent progress in the oxygen-related catalysis (e.g., oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and metal-air batteries) of hollow-structured transition metal oxides is discussed. Through a comprehensive outline of hollow-structured spinels, perovskites, rutiles, etc., a rational design strategy is provided for an enhanced oxygen-related catalysis performance from the viewpoint of crystal structures. Urgent challenges and further research directions are presented for hollow-structured transition metal oxides toward excellent oxygen-related catalysis.

19.
ChemSusChem ; 12(5): 1000-1010, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30565883

RESUMO

Ni/CeO2 enables either methane decomposition or water electrolysis for pure hydrogen production. Ni/CeO2 , prepared by a sol-gel method with only one heat treatment step, was used to catalyze methane decomposition for the generation of H2 . The solid byproduct, Ni/CeO2 /carbon nanotube (CNT), was further employed as an electrocatalyst in the hydrogen evolution reaction (HER) for H2 production. The Ni/CeO2 catalyst exhibits excellent activity for methane decomposition because CeO2 prevents carbon encapsulation of Ni nanoparticles during the preparation process and forms a special metal-support interface with Ni. The derived CNTs act as antenna to improve conductivity and promote the dispersion of agglomerated Ni/CeO2 . In addition, they provide H2 diffusion paths and prevent Ni/CeO2 from peeling off the HER electrode. Although long-term methane decomposition reduces the HER activity of Ni/CeO2 /CNTs (owing to degradation of the delicate Ni/CeO2 interface), the tunable nature of the synthesis makes this an attractive sustainable approach to synthesize future high-performance materials.

20.
Small ; 15(29): e1803513, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30427576

RESUMO

Identifying the relationship between catalytic performance and material structure is crucial to establish the design principle for highly active catalysts. Deficiency in BO bond covalency induced by lattice distortion severely restricts the oxygen reduction reaction (ORR) performance for ABO3 -type perovskite oxides. Herein, a rearrangement of hybridization mode for BO bond is used to tune the overlap of the electron cloud between B 3d and O 2p through A-stie doping with larger radius ions. The BO bond covalency is strengthened with a BOB bond angle recovered from intrinsic structural distortion. As a result, the adsorption and the reduction process for O2 on the oxide surface can be promoted via shifting the O-2p band center toward the Fermi Level. Simultaneously, the spin electrons in the Mn 3d orbit become more parallel. It will lead to a high electrical conductivity by the enhanced double exchange process and thereof mitigate the ORR efficiency loss. Further density functional theory calculation reveals that a flat [BO2 ] plane will make contribution to the charge transfer process from lattice oxygen to adsorbed oxygen (mediated with B ions). Through such exploration of the effect of crystal structure on the electronic state of perovskite oxides, a novel insight into design of highly active ORR catalysts is offered.

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