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1.
Small ; 20(22): e2309176, 2024 May.
Article in English | MEDLINE | ID: mdl-38150625

ABSTRACT

Metal nanoclusters providing maximized atomic surface exposure offer outstanding hydrogen evolution activities but their stability is compromised as they are prone to grow and agglomerate. Herein, a possibility of blocking metal ion diffusion at the core of cluster growth and aggregation to produce highly active Ru nanoclusters supported on an N, S co-doped carbon matrix (Ru/NSC) is demonstrated. To stabilize the nanocluster dispersion, Ru species are initially coordinated through multiple Ru─N bonds with N-rich 4'-(4-aminophenyl)-2,2:6',2''-terpyridine (TPY-NH2) ligands that are subsequently polymerized using a Schiff base. After the pyrolysis of the hybrid composite, highly dispersed ultrafine Ru nanoclusters with an average size of 1.55 nm are obtained. The optimized Ru/NSC displays minimal overpotentials and high turnover frequencies, as well as robust durability both in alkaline and acidic electrolytes. Besides, outstanding mass activities of 3.85 A mg-1 Ru at 50 mV, i.e., 16 fold higher than 20 wt.% Pt/C are reached. Density functional theory calculations rationalize the outstanding performance by revealing that the low d-band center of Ru/NSC allows the desorption of *H intermediates, thereby enhancing the alkaline HER activity. Overall, this work provides a feasible approach to engineering cost-effective and robust electrocatalysts based on carbon-supported transition metal nanoclusters for future energy technologies.

2.
Small ; 20(27): e2311196, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38308074

ABSTRACT

Tin sulfide (Sn2S3) has been recognized as a potential anode material for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) due to its high theoretical capacities. However, the sluggish ion diffusion kinetics, low conductivity, and severe volume changes during cycling have limited its practical application. In this study, Sn2S3 quantum dots (QDs) (≈1.6 nm) homogeneously embedded in an N, S co-doped carbon fiber network (Sn2S3-CFN) are successfully fabricated by sequential freeze-drying, carbonization, and sulfidation strategies. As anode materials, the Sn2S3-CFN delivers high reversible capacities and excellent rate capability (300.0 mAh g-1 at 10 A g-1 and 250.0 mAh g-1 at 20 A g-1 for SIBs; 165.3 mAh g-1 at 5 A g-1 and 100.0 mAh g-1 at 10 A g-1 for PIBs) and superior long-life cycling capability (279.6 mAh g-1 after 10 000 cycles at 5 A g-1 for SIBs; 166.3 mAh g-1 after 5 000 cycles at 2 A g-1 for PIBs). According to experimental analysis and theoretical calculations, the exceptional performance of the Sn2S3-CFN composite can be attributed to the synergistic effect of the conductive carbon fiber network and the Sn2S3 quantum dots, which contribute to the structural stability, reversible electrochemical reactions, and superior electron transportation and ions diffusion.

3.
Chemistry ; 27(6): 2104-2111, 2021 Jan 26.
Article in English | MEDLINE | ID: mdl-33174628

ABSTRACT

A general and simple strategy is realized for the first time for the preparation of metal sulfide (Mx Sy ) nanoparticles immobilized into N/S co-doped carbon (NSC) through a one-step pyrolysis method. The organic ligand 1,5-naphthalenedisulfonic acid in the metal-organic framework (MOF) precursor is used as a sulfur source, and metal ions are sulfurized in situ to form Mx Sy nanoparticles, resulting in the formation of Mx Sy /NSC (M=Fe, Co, Cu, Ni, Mn, Zn) composites. Benefiting from the Mx Sy nanoparticles and conductive carbon, a synergistic effect of the composite is achieved. For instance, the composite of Fe7 S8 /NSC as an anode displays excellent long-term cycling stability in lithium/sodium ion batteries. At 5 A g-1 , large capacities of 645 mA h g-1 and 426.6 mA h g-1 can be retained after 1500 cycles for the lithium-ion battery and after 1000 cycles for the sodium-ion battery, respectively.

4.
ACS Appl Bio Mater ; 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38952293

ABSTRACT

Dopamine, alongside norepinephrine and epinephrine, belongs to the catecholamine group, widely distributed across both plant and animal kingdoms. In mammals, these compounds serve as neurotransmitters with roles in glycogen mobilization. In plants, their synthesis is modulated in response to stress conditions aiding plant survival by emitting these chemicals, especially dopamine that relieves their resilience against stress caused by both abiotic and biotic factors. In present studies, there is a lack of robust methods to monitor the operations of dopamine under stress conditions or any adverse situations across the plant's developmental stages from cell to cell. In our study, we have introduced a groundbreaking approach to track dopamine generation and activity in various metabolic pathways by using the simple nitrogen and sulfur co-doped carbon quantum dots (N, S-CQDs). These CQDs exhibit dominant biocompatibility, negligible toxicity, and environmentally friendly characteristics using a quenching process for fluorometric dopamine detection. This innovative nanomarker can detect even small amounts of dopamine within plant cells, providing insights into plant responses to strain and anxiety. Confocal microscopy has been used to corroborate this occurrence and to provide visual proof of the process of binding dopamine with these N, S-CQDs inside the cells.

5.
J Colloid Interface Sci ; 658: 373-382, 2024 Mar 15.
Article in English | MEDLINE | ID: mdl-38113546

ABSTRACT

In this work, potassium acetate (KAc) was added during the synthesis of a Zn-Fe based metal-organic framework (Fe-ZIF-8) to increase the fixed amount of Fe while simultaneously enhancing the number of pores. Electrospinning was utilized to embed KAc-modified Fe-ZIF-8 (Fe-ZIF-8-Ac) into the polyacrylonitrile nanofiber mesh, to obtain a network composite (Fe@NC-Ac) with hierarchical porous structure. Fe@NC-Ac was co-pyrolyzed with thiourea, resulting in Fe, N, S co-doped carbon electrocatalyst. The electrochemical tests indicated that the prepared catalyst displayed relatively remarkable oxygen reduction reaction (ORR) catalytic activity, with an onset potential (Eonset) of 1.08 V (vs. reversible hydrogen electrode, RHE) and a half-wave potential (E1/2) of 0.94 V, both higher than those of the commercial Pt/C (Eonset = 0.95 V and E1/2 = 0.84 V), respectively. Assembled into Zn-air batteries, the optimized catalyst exhibited higher open circuit voltage (1.698 V) and peak power density (90 mW cm-2) than those of the commercial 20 wt% Pt/C (1.402 V and 80 mW cm-2), respectively. This work provided a straightforward manufacturing strategy for the design of hierarchical porous carbon-based ORR catalysts with desirable performance.

6.
Talanta ; 265: 124853, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-37379753

ABSTRACT

A straightforward, rapid, and selective fluorescent probe for determination of tilmicosin has been developed based on novel nitrogen and sulfur co-doped CDs (NS-CD). The NS-CDs were synthesized, for the first time, through green, simple one step microwave pyrolysis in only 90 s using glucose as carbon source and l-cysteine as nitrogen and sulfur source. This proposed synthesis method was energy-efficient and resulted in NS-CDs with high production yield (54.27 wt%) and narrow particle size distribution. Greenness of NS-CDs synthesis method was assessed using EcoScale and was proven to be excellent green synthesis. The produced NS-CDs were applied as a nano-probe for determination of tilmicosin in its marketed formulation and milk based on dynamic quenching mechanism. The developed probe showed a good performance for tilmicosin detection in marketed oral solution and pasteurized milk and linearity range of 9-180 µM and 9-120 µM, respectively.


Subject(s)
Fluorescent Dyes , Quantum Dots , Carbon , Microwaves , Nitrogen , Sulfur
7.
Nanomaterials (Basel) ; 13(3)2023 Jan 21.
Article in English | MEDLINE | ID: mdl-36770405

ABSTRACT

S-doping emerged as a promising approach to further improve the catalytic performance of carbon-based materials for organic synthesis. Herein, a facile and gram-scale strategy was developed using zeolitic imidazole frameworks (ZIFs) as a precursor for the fabrication of the ZIF-derived N, S co-doped carbon-supported zinc single-atom catalyst (CNS@Zn1-AA) via the pyrolysis of S-doped ZIF-8, which was modified by aniline, ammonia and thiourea and prepared by one-pot ball milling at room temperature. This catalyst, in which Zn is dispersed as the single atom, displays superior activity in N-alkylation via the hydrogen-borrowing strategy (120 °C, turnover frequency (TOF) up to 8.4 h-1). S-doping significantly enhanced the catalytic activity of CNS@Zn1-AA, as it increased the specific surface area and defects of this material and simultaneously increased the electron density of Zn sites in this catalyst. Furthermore, this catalyst had excellent stability and recyclability, and no obvious loss in activity after eight runs.

8.
Food Chem ; 372: 131142, 2022 Mar 15.
Article in English | MEDLINE | ID: mdl-34600193

ABSTRACT

To determine the glutathione (GSH) content in vegetables, an "on-off-on" fluorescence probe was developed by a synthesis of nitrogen and sulfur co-doped carbon dots (N,S-CDs) using the microwave pyrolysis considering citric acid and L-cysteine as precursors. The fluorescence of N,S-CDs was quenched by adding Cu2+ at a concentration of 20-200 µmol/L due to the inner filter effect. The quenched fluorescence of N,S-CDs@Cu2+ system was recovered by adding the GSH at a concentration of 10-150 µmol/L due to the sulfhydryl-metal compound mechanism. By observing the GSH concentrations measured by our N,S-CDs@Cu2+ system vs. a traditional fluorescent chelating method, the two measurements provided the GSH data with a good consistence by showing the RSD range of 1.86%-2.27%. This indicates the validation and novelty of our N,S-CDs@Cu2+ system as being a powerful fluorescent probe for effectively and efficiently determining the GSH in vegetables.


Subject(s)
Glutathione , Quantum Dots , Carbon , Fluorescent Dyes , Nitrogen , Spectrometry, Fluorescence , Sulfur , Vegetables
9.
Nanomaterials (Basel) ; 12(17)2022 Sep 02.
Article in English | MEDLINE | ID: mdl-36080084

ABSTRACT

A composite of Mo2C nanoparticles dispersed onto a nitrogen and sulfur co-doped carbon scaffold (Mo2C/N,S-C) was prepared by a simple and environmentally friendly method of one-pot annealing of MoCl5, urea, and lignosulfonate under a N2 atmosphere at 700 °C. Lignosulfonate, a by-product of the sulfite pulping process, was employed as a feedstock to fabricate the S-doped carbon scaffold and carbide simultaneously, and urea acted as a nitrogen source for N-doping to carbon. The as-prepared Mo2C/N,S-C catalyst showed high performance for the hydrogen evolution reaction (HER), with a small overpotential of 105 mV at 10 mAcm-2, and good stability for 3000 cycles. The improved HER performance of the Mo2C/N,S-C originated from the interplay between the highly active Mo2C nanoparticles and the N,S co-doped carbon scaffold with its high electrical conductivity and large surface area. Furthermore, N,S co-doping to carbon improved the hydrophilicity of the catalyst surface, thus further enhancing the HER activity.

10.
J Colloid Interface Sci ; 611: 255-264, 2022 Apr.
Article in English | MEDLINE | ID: mdl-34953458

ABSTRACT

Carbon dots (CDs) have been widely used in recent years because of their excellent water solubility and abundant surface functional groups. However, compared with quantum dots or biological probes, the quantum yield of CDs is lower, and the fluorescence mainly concentrated in the blue-green range, which significantly limits the biological applications of CDs. Heteroatoms doping is the most common method to improve the luminescence of CDs. In this work, nitrogen and sulfur co-doped luminescent CDs were successfully synthesized by microwave assisted method using glutathione (GSH) and p-phenylenediamine (PPD) as raw materials. It can emit bright green fluorescence in ethanol solution, and the maximum emission wavelength is 535 nm when excited at 374 nm, and the absolute quantum yield is as high as 63%. Iron ion (Fe3+) can interact with the functional groups on the surface of the CDs to form CDs/Fe3+, which is a non-fluorescence complex, and Fe3+ can be reduced to ferrous ion (Fe2+). In other words, the reaction mechanism of CDs and Fe3+ is a combination of dynamic quenching and static quenching. The fluorescence of CDs quenched by Fe3+ can be restored by thiol, because there is a stronger binding force between sulfhydryl (-SH) on the surface of thiol and Fe3+, which enables CDs to be released. In addition, the CDs has good biocompatibility and stability, indicating that it has excellent potential in bioimaging. This discovery will expand the application of CDs in the fields of biosensing and imaging.


Subject(s)
Carbon , Quantum Dots , Fluorescent Dyes , Iron , Nitrogen , Sulfhydryl Compounds , Sulfur
11.
Environ Sci Pollut Res Int ; 29(37): 56684-56695, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35347616

ABSTRACT

Sunlight active blue emissive zirconium, nitrogen, and sulfur co-doped carbon dots (Zr-N-S-CDs) have been synthesized by microwave-induced pyrolysis for achieving efficient photocatalytic degradation of pollutant malachite green dye (MG) in water. Surface morphology studies using high-resolution transmission electron microscopy confirmed the formation of spherical-shaped CDs with an absorbance peak at 350 nm and emission peak at 437 nm in UV-vis and fluorescence spectroscopy, respectively. Surface functional groups, elemental composition, and metal/non-metal co-doping were confirmed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. To understand the photocatalytic performance of Zr-N-S-CDs, various parameters, such as the source of energy, concentration of dye, catalyst dosage, and change in pH, were investigated. MG dye (20 ppm) at a pH 7 with 0.5 mg/mL of Zr-N-S-CDs could be photodegraded efficiently in 90 min under sunlight (99%) compared to dark and artificial light conditions. Moreover, real-time analysis of degradation rate could be conveniently calculated by integrating the colorimetric responses of MG dye with RGB values obtained by the "Color Picker" app of a smartphone. The degradation rate obtained using a smartphone (97.89%) was found to be in agreement with the UV-vis spectroscopy (99%), thus, providing a new, handy, and instrument-free route for speedy and quantitative estimation of the degradation of hazardous MG dye by Zr-N-S-CDs.


Subject(s)
Carbon , Water , Carbon/chemistry , Coloring Agents , Nitrogen/chemistry , Photoelectron Spectroscopy , Rosaniline Dyes , Smartphone , Sulfur/chemistry , Water/chemistry , Zirconium/chemistry
12.
Sci Total Environ ; 805: 150340, 2022 Jan 20.
Article in English | MEDLINE | ID: mdl-34818762

ABSTRACT

Oxygen reduction reaction (ORR) electrocatalysts have been considered as one of the key components in microbial fuel cells (MFCs). Heteroatom-doped carbon quantum dots (CQDs) derived from biomass have attracted wide attention due to their rich functional groups, excellent properties, and environmental friendliness. Herein, orange-peels-derived N, S co-doped carbon quantum dots (N, S-CQDs) are in-situ anchored on copper-vacancy-rich Cu nanowires/Cu foam (V-Cu NWs/CF), obtaining the N, S-CQDs/Cu2O-Cu NWs, to catalyze ORR in MFCs. The interaction between N, S-CQDs and V-Cu NWs/CF from the N, S-CQDs/Cu2O-Cu NWs is bridged by the C-S-Cu bond, which is demonstrated to be the active site towards ORR and plays an important role in promoting electron transfer by in-situ Raman and X-ray photoelectron spectroscopy characterizations. In MFCs, the maximum power density (924.5 ± 32.5 mW·m-2) of N, S-CQDs/Cu2O-Cu NWs is 1.34 times that of Pt/C (686.5 ± 28.0 mW·m-2), and its long-term stability also outperforms the Pt/C. This study provides inspiration for synthesis of efficient ORR electrocatalysts with metal-ligand active sites creating by heteroatom-doped CQDs and cationic-metal-vacancy-rich materials.


Subject(s)
Bioelectric Energy Sources , Nanowires , Quantum Dots , Carbon , Catalytic Domain , Copper , Electrodes
13.
J Colloid Interface Sci ; 624: 680-690, 2022 Oct 15.
Article in English | MEDLINE | ID: mdl-35691232

ABSTRACT

It is still challengeable but significant to rationally develop dual-metal single-atom catalysts with rich accessible active sites and excellent intrinsic catalytic activity towards oxygen reduction reaction (ORR). Herein, we present a novel dual-metal single-atom catalyst, Fe and Zn single atoms homogenously anchored on carbon nanotubes inlaid N, S-doped hollow carbon polyhedrons (FeZn-NSC), synthesized by facile iron-salt impregnation and high-temperature pyrolysis for zeolitic imidazolate framework-8. Due to the synergistic effects of the hierarchical porous nanoarchitecture with high specific surface area (795.48 m2 g-1), N, S co-doped hollow carbon polyhedrons, in-situ grown highly conductive carbon nanotubes, and high loading of dual-metal single-atoms of Fe (3.12 wt%) and Zn (3.71 wt%), the optimized FeZn-NSC delivers outstanding ORR performance with high half-wave potential of 0.87 V, low Tafel slope of 44.7 mV dec-1, long-term durability, and strong tolerance of methanol crossover. This work provides a strategy to rationally design and facilely synthesize dual-metal single-atom catalysts with high ORR activity.

14.
Spectrochim Acta A Mol Biomol Spectrosc ; 252: 119506, 2021 May 05.
Article in English | MEDLINE | ID: mdl-33561684

ABSTRACT

Azithromycin (AZM)1 is one of the most widely used antibiotics. AZM abuse is easy to cause great harm to human body, so developing a rapid and sensitive method to detect AZM is of great importance. Herein, 3-aminothiophenol as only reaction precursor, nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs)2 were fabricated by one-step hydrothermal carbonization method. All characteristics demonstrate that N,S-CQDs possess good water solubility, high fluorescence stability and low cytotoxicity. Without being disturbed by amino acids and drugs, the most interesting finding is that AZM can efficiently quench the fluorescence of N,S-CQDs by a synergistic effect of electrostatic interaction and static quenching. A fluorescent probe for the detection of AZM was constructed with high selectivity and good sensitivity, achieving two linear ranges of 2.5-32.3 µM and 37.2-110 µM and a limit of detection of 0.76 µM. The proposed fluorescent method was used for the detection of AZM in cells with fulfilling results. More importantly, the fluorescent probe was successfully used to the detection of AZM in tablets and human urine with recovery rate and relative standard deviations of 98.2-104.8% and 0.04-3.46%, respectively, which was confirmed by the standard method of HPLC-UV. This finding illustrates the usefulness and feasibility of N,S-CQDs as an effective fluorescent probe for the detection of AZM in tablets and human urine, which is helpful for supervising and guiding pharmacy.


Subject(s)
Quantum Dots , Azithromycin , Carbon , Humans , Nitrogen , Tablets
15.
J Colloid Interface Sci ; 604: 368-377, 2021 Dec 15.
Article in English | MEDLINE | ID: mdl-34265691

ABSTRACT

Transition metal sulfides, as an important class of inorganics, have been shown to be potential high-performance electrode candidates for lithium-ion batteries (LIBs) in account of their high activity towards lithium storage, rich types and diverse structures. Despite these advantages, structure degradation related with volume variations upon electrochemical cycling restricts their further development. In this present study, a unique hybrid structure with ultrafine heazlewoodite nanoparticles (less than 10 nm) in-situ confined in nitrogen and sulfur dual-doped carbon (Ni3S2@NSC) was constructed though a facile pyrolysis process, using a novel Ni-based metal chelates as the precursor. Specifically, enhanced structure stability, shortened Li+ migration distance and improved reaction dynamics can be obtained simultaneously in the designed structure, thereby allowing to realize high lithium storage performance. Consequently, a remarkable reversible capacity of 955.9 mAh g-1 (0.1 A g-1 after 100 cycles) and a superior long-term cycling stability up to 1200 cycles (863.7 mAh g-1 at 1.0 A g-1) are obtained. Importantly, the fundamental understanding on the improved lithium storage of Ni3S2@NSC based on the synergistic coupling reveals that the combination between Ni3S2 and NSC at the hetero-interface through the doped sulfur atoms contributes to the integrity of electrode and improved kinetics.

16.
Materials (Basel) ; 14(13)2021 Jun 23.
Article in English | MEDLINE | ID: mdl-34201568

ABSTRACT

In this paper we report the synthesis of a N, S co-doped metal free carbon cryogel obtained from a marine biomass derived precursor using urea as nitrogen source. Natural carrageenan intrinsically contains S and inorganic salt. The latter also serves as an activating agent during the pyrolytic step. The overall 11.6 atomic % surface heteroatom concentration comprises 5% O, 4.6% N and 1% S. The purified and annealed final carbon (CA) has a hierarchical pore structure of micro-, meso- and macropores with an apparent surface area of 1070 m2/g. No further treatment was applied. The gas adsorption potential of the samples was probed with H2, CO2 and CH4, while the electrocatalytic properties were tested in an oxygen reduction reaction. The atmospheric CO2 and CH4 storage capacity at 0 °C in the low pressure range is very similar to that of HKUST-1, with the CO2/CH4 selectivity below 20 bar, even exceeding that of the MOF, indicating the potential of CA in biogas separation. The electrocatalytic behavior was assessed in an aqueous KOH medium. The observed specific gravimetric capacitance 377 F/g was exceeded only in B, N dual doped and/or graphene doped carbons from among metal free electrode materials. The CA electrode displays almost the same performance as a commercial 20 wt% Pt/C electrode. The oxygen reduction reaction (ORR) exhibits the 4-electron mechanism. The 500-cycle preliminary stability test showed only a slight increase of the surface charge.

17.
Mater Sci Eng C Mater Biol Appl ; 118: 111478, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33255057

ABSTRACT

The fluorescent boron, nitrogen and sulfur co-doped carbon dots (BNSCDs) were prepared by simple hydrothermal reaction of 4-carboxyphenylboronic acid and 2,5-diaminobenzenesulfonic acid at 200 °C for 8 h. The fluorescence of the BNSCDs could be quenched by Fe3+ based on the electron transfer between Fe3+ and BNSCDs, so a label-free, good selectivity and high sensitivity method for Fe3+determination was established with linear range and LOD of 1.5-692 µmol/L and 87 nmol/L, respectively. And then the fluorescent probe was employed for detection of Fe3+ in tap water, coal gangue, fly ash and food samples successfully. Moreover, the as-prepared BNSCDs could serve as a novel pH fluorescent probe in the range of pH 1.60-7.00, which could be attributed to the proton transfer of carboxyl groups on the surface of BNSCDs. More importantly, the pH fluorescent probe possesses fast, real-time and low toxicity, applying for intracellular pH fluorescence imaging in HIC, HIEC, LO2 and SMMC7721 cells. In view of its simplicity, timely response and outstanding compatibility, the as-fabricated BNSCDs show the potential applications in water quality and solid waste monitoring, food detection, real-time measuring of intracellular pH change in vitro.


Subject(s)
Citrus sinensis , Quantum Dots , Boron , Carbon , Fluorescent Dyes , Hydrogen-Ion Concentration , Nitrogen , Spectrometry, Fluorescence , Sulfur
18.
Nanomicro Lett ; 11(1): 63, 2019 Aug 01.
Article in English | MEDLINE | ID: mdl-34138003

ABSTRACT

Metallic Sn has provoked tremendous progress as an anode material for sodium-ion batteries (SIBs). However, Sn anodes suffer from a dramatic capacity fading, owing to pulverization induced by drastic volume expansion during cycling. Herein, a flexible three-dimensional (3D) hierarchical conductive network electrode is designed by constructing Sn quantum dots (QDs) encapsulated in one-dimensional N,S co-doped carbon nanofibers (NS-CNFs) sheathed within two-dimensional (2D) reduced graphene oxide (rGO) scrolls. In this ingenious strategy, 1D NS-CNFs are regarded as building blocks to prevent the aggregation and pulverization of Sn QDs during sodiation/desodiation, 2D rGO acts as electrical roads and "bridges" among NS-CNFs to improve the conductivity of the electrode and enlarge the contact area with electrolyte. Because of the unique structural merits, the flexible 3D hierarchical conductive network was directly used as binder- and current collector-free anode for SIBs, exhibiting ultra-long cycling life (373 mAh g-1 after 5000 cycles at 1 A g-1), and excellent high-rate capability (189 mAh g-1 at 10 A g-1). This work provides a facile and efficient engineering method to construct 3D hierarchical conductive electrodes for other flexible energy storage devices.

19.
Anal Chim Acta ; 1047: 179-187, 2019 Jan 24.
Article in English | MEDLINE | ID: mdl-30567648

ABSTRACT

Reliable and simple detection methods for chemotherapeutic agent contaminants, such as methotrexate, are required to minimize their possible toxic threat. However, detecting them remains a challenging in environmental and biological analysis. Here, we developed a fluorescent N, S co-doped carbon quantum dots (N, S co-doped CQDs) probe to detect methotrexate on the basis of the inner filter effect of fluorescence. Under optimized conditions, the fluorescent probe exhibits high sensitivity and specific selectivity with a linear detection range from 0.4 µg/mL to 41.3 µg/mL and a low detection limit of 12 ng/mL (S/N = 3). Further, this N, S co-doped CQDs fluorescent probe can be used to analyze extracellular fluids and wastewater samples satisfactorily, thereby showing a remarkable potential for broad applications in biological molecule determination and environmental analysis.


Subject(s)
Carbon/chemistry , Fluorescent Dyes/chemistry , Methotrexate/analysis , Quantum Dots/chemistry , A549 Cells , Energy Transfer , Fluorescence , Humans , Limit of Detection , Spectrometry, Fluorescence/methods , Wastewater/analysis
20.
Front Chem ; 6: 78, 2018.
Article in English | MEDLINE | ID: mdl-29755966

ABSTRACT

Highly porous carbon with large surface areas is prepared using cotton as carbon sources which derived from discard cotton balls. Subsequently, the sulfur-nitrogen co-doped carbon was obtained by heat treatment the carbon in presence of thiourea and evaluated as Lithium-ion batteries anode. Benefiting from the S, N co-doping, the obtained S, N co-doped carbon exhibits excellent electrochemical performance. As a result, the as-prepared S, N co-doped carbon can deliver a high reversible capacity of 1,101.1 mA h g-1 after 150 cycles at 0.2 A g-1, and a high capacity of 531.2 mA h g-1 can be observed even after 5,000 cycles at 10.0 A g-1. Moreover, excellently rate capability also can be observed, a high capacity of 689 mA h g-1 can be obtained at 5.0 A g-1. This superior lithium storage performance of S, N co-doped carbon make it as a promising low-cost and sustainable anode for high performance lithium ion batteries.

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