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1.
Chem Commun (Camb) ; 55(77): 11642, 2019 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-31512684

RESUMO

Correction for 'Synthesis of hydrophobic and hydrophilic TiO2 nanofluids for transformable surface wettability and photoactive coating' by Jie Hu et al., Chem. Commun., 2019, 55, 9275-9278.

2.
ACS Appl Mater Interfaces ; 11(36): 32957-32968, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31424192

RESUMO

The development of lithium-ion batteries using transition metal oxides has recently become more attractive, due to their higher specific capacities, better rate capability, and high energy densities. Herein, the in situ growth of advanced mesoporous CuO/O-doped g-C3N4 nanospheres is carried out in a two step hydrothermal process at 180 °C and annealing in air at 300 °C. When used as an anode material, the CuO/O-doped g-C3N4 nanospheres achieve a high reversible discharge specific capacity of 738 mAhg-1 and a capacity retention of ∼75.3% after 100 cycles at a current density 100 mAg-1 compared with the pure CuO (412 mAhg-1, 47%) and O-doped g-C3N4 (66 mAhg-1, 53%). Even at high current density 1 Ag-1, they exhibit a reversible discharge specific capacity of 503 mAhg-1 and capacity retention ∼80% over 500 cycles. The excellent electrochemical performance of the CuO/O-doped g-C3N4 nanocomposite is attributed to the following factors: (I) the in situ growing CuO/O-doped g-C3N4 avoids CuO nanoparticle aggregation, leading to the improved lithium ion transfer and electrolyte penetration inside the CuO/O-doped g-C3N4 anode, thus promoting the utilization of CuO; (II) the porous structure provides efficient space for Li+ transfer during the insertion/extraction process to avoid large volume changes; (III) the O-doping g-C3N4 decreases its band gap, ensuring the increased electrical conductivity of CuO/O-doped g-C3N4; and (IV) the strong interaction between CuO and O-doped g-C3N4 ensures the stability of the structure during cycling.

3.
Chem Commun (Camb) ; 55(63): 9275-9278, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31259354

RESUMO

Two modified TiO2 nanofluids were developed, with either hydrophobic or hydrophilic properties. The hydrophobic TiO2 nanofluid, embedded in an organo-silyl salt, could be transformed into a hydrophilic TiO2 nanofluid by exchange of the chloride with an organo-sulphonate ion. Both modified TiO2 nanofluids exhibited high fluidity, thermal stability and photoactivity.

4.
J Colloid Interface Sci ; 551: 111-118, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078096

RESUMO

Photocatalytic hydrogen (H2) production based on semiconductors is important to utilize solar light for clean energy and environment. Herein, we report a visible light responsive heterostructure, designed and constructed by molybdenum disulfide quantum dots (MoS2-QDs) in-situ seeds-directing growth and self-assemble of zinc indium sulfide (ZnIn2S4) nanosheet to ensure their full contact through a simple one-step solvothermal method for highly improved visible light H2 production. The MoS2-QDs in-situ seeds-directing ZnIn2S4 heterostructure not only builds heterojunctions between MoS2 and ZnIn2S4 to spatially separate the photogenerated electrons and holes, but also serves as the active sites trapping photogenerated electrons to facilitate H2 evolution. As a result, MoS2-QDs/ZnIn2S4 exhibits high photocatalytic activity for H2 production, and the optimized 2 wt% MoS2-QDs/ZnIn2S4 (2MoS2-QDs/ZnIn2S4) heterostructure exhibits the highest H2 evolution rate of 7152 umol·h-1·g-1 under visible light, ∼9 times of pure ZnIn2S4. Our strategy here could shed some lights on developing noble-metal free heterostructures for highly efficient photocatalytic H2 production.

5.
Nanoscale ; 11(14): 6970-6981, 2019 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-30916057

RESUMO

The lithium-selenium (Li-Se) battery has attracted growing interest recently due to its high energy density and theoretical capacity. However, the shuttle effect and volume change during cycling severely hinder its further application. In this work, we report a metal-organic framework (MOF)-derived nitrogen-doped core-shell hierarchical porous carbon (N-CSHPC) with interconnected meso/micropores to effectively confine Se for high-performance Li-Se batteries. The micropores were located at the ZIF-8-derived core and the ZIF-67-derived shell, while mesopores appeared at the core-shell interface after the pyrolysis of the core-shell ZIF-8@ZIF-67 precursor. Such a special hierarchical porous structure effectively confined selenium and polyselenides to prevent their dissolution from the pores and also alleviated the volume change. In particular, in situ nitrogen doping, which afforded N-CSHPC, not only improved the electrical conductivity of Se but also provided strong chemical adsorption on Li2Se, as confirmed by density functional theory calculations. On the basis of dual-physical confinement and strong chemisorption, Se/N-CSHPC-II (molar ratio of Co source to Zn source of 1.0 in the core-shell ZIF-8@ZIF-67 precursor) exhibited reversible capacities of up to 555 mA h g-1 after 150 cycles at 0.2 C and 462 mA h g-1 after 200 cycles at 0.5 C and even a discharge capacity of 432 mA h g-1 after 200 cycles at 1 C. Our demonstration here suggests that the carefully designed Se/C composite can improve the reversible capacity and cycling stability of Se cathodes for Li-Se batteries.

6.
J Colloid Interface Sci ; 539: 585-597, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30611054

RESUMO

Ternary zinc oxide/bismuth vanadate/three-dimensional ordered macroporous titanium dioxide (ZnO/BiVO4/3DOM TiO2) heterojuncted nanocomposites with cascade electronic band structures were successfully designed and synthesized for visible light photodegradation of two different molecules: Rhodamine B (RhB) and Tartrazine. The photocatalytic active species have been investigated by using electron scavenger (AgNO3) and hole scavenger (Triethanolamine: TEOA). The band edge positions of each component in tenary nanocomposites have been measured by using photoelectrochemical Mott-Schottky method and valence band XPS (VB-XPS) spectroscopy. Within the heterojunction, charges are favorably and spatially separated through the gradient potential at the interfaces. This largely suppresses the recombination of photogenerated electrons and holes. Furthermore, 3DOM inverse opal structure is beneficial for high diffusion efficiency and highly accessible surface area of reactants and light and multiple scattering for light harvesting. Consequently, these heterojuncted nanocomposites exhibit highly enhanced photocatalytic performance compared with pure BiVO4 nanostructure, and binary BiVO4/3DOM TiO2, ZnO/BiVO4 nanocomposites. A detailed mechanism of charge transfer is proposed for these ternary ZnO/BiVO4/3DOM TiO2 nanocomposites on the basis of a large series of spectroscopic and photocatalytic results. Our work demonstrates clearly that coupling multicomponent semiconductors with different energy levels of conduction and valence bands can significantly increase the photogenerated charge carriers through the efficient charge separation across their multiple interfaces. This work gives some new ideas on developing new visible light responsive nanocomposites for highly efficient solar energy utilization.

7.
J Colloid Interface Sci ; 538: 99-107, 2018 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-30500471

RESUMO

Graphitic carbon nitride (g-C3N4) is a visible light active semiconductor. However, low conductivity and high recombination rate of photogenerated electrons and holes limit its application in photocatalysis. In this work, we design and synthesize hierarchically porous zinc oxide/graphitic carbon nitride (ZnO/g-C3N4) microspheres with type-II heterojunction to effectively degrade rhodamine B (RhB) via increasing the charge-separation efficiency. The ultraviolet-visible (UV-Vis) absorption spectra, Mott-Schottky plots and valence band X-ray photoelectron spectroscope confirm the formation of type-II heterojunction between ZnO nanocrystals and g-C3N4 nanosheets. As a result, the 1.5-ZnO/g-C3N4 composite (the mass ratio of zinc acetate dihydrate to g-C3N4 is 1.5) exhibits the highest photocatalytic activity with good stability and higher photocatalytic degradation rate comparing to pure g-C3N4 and pure ZnO. In addition, our results confirm that O2- and h+ are the main active species for ZnO/g-C3N4 in degradation of RhB.

8.
Artigo em Inglês | MEDLINE | ID: mdl-30360050

RESUMO

The number of patients suffering from diseases linked with hormone deficiency (e.g. type 1 diabetes mellitus) has significantly increased in recent years. As organ transplantation presents its limits, the design of novel robust devices for cell encapsulation is of great interest. The current study reports the design of a novel hybrid alginate microcapsule reinforced by titania via a biocompatible synthesis from an aqueous stable titania precursor (TiBALDH) and a cationic polyamine (PDDAC) under mild conditions. The biocompatibility of this one-pot synthesis was confirmed by evaluation of the cytotoxicity of the precursor, additive, product and by-product. The morphology, structure and properties of the obtained hybrid microcapsule were characterized in detail. The microcapsule displayed mesoporous, which was a key parameter to allow the diffusion of nutrients and metabolites and to avoid the entry of immune defenders. The hybrid microcapsule also showed enhanced mechanical stability compared to the pure alginate microcapsule, making it an ideal candidate as a cell reservoir. HepG2 model cells encapsulated in the hybrid microcapsules remained intact for 43 days as highlighted by fluorescent viability probes, their oxygen consumption, and their albumin secretion. The study provides a significant progress in the conception of the robust and biocompatible reservoirs of animal cells for cell therapy.

9.
Chem Commun (Camb) ; 54(86): 12250-12253, 2018 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-30318529

RESUMO

A porous TiO2/BaTiO3 heterostructure composite has been developed as a polysulfide mediator for lithium-sulfur batteries. Superior electrochemical performance has been achieved, mainly attributed to the synergy of TiO2 and BaTiO3 with dual affinity to polysulfides from chemical and ferroelectric-induced polarization effects, and enhanced redox kinetics propelled by the TiO2/BaTiO3 heterojunctions.

10.
Front Chem ; 6: 428, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30320061

RESUMO

CuO is a promising anode material for lithium-ion batteries due to its high theoretical capacity, low cost, and non-toxicity. However, its practical application has been plagued by low conductivity and poor cyclability. Herein, we report the facile synthesis of porous defective CuO nanosheets by a simple wet-chemical route paired with controlled annealing. The sample obtained after mild heat treatment (300°C) exhibits an improved crystallinity with low dislocation density and preserved porous structure, manifesting superior Li-ion storage capability with high capacity (~500 mAh/g at 0.2 C), excellent rate (175 mAh/g at 2 C), and cyclability (258 mAh/g after 500 cycles at 0.5 C). The enhanced electrochemical performance can be ascribed to the synergy of porous nanosheet morphology and improved crystallinity: (1) porous morphology endows the material a large contact interface for electrolyte impregnation, enriched active sites for Li-ion uptake/release, more room for accommodation of repeated volume variation during lithiation/de-lithiation. (2) the improved crystallinity with reduced edge dislocations can boost the electrical conduction, reducing polarization during charge/discharge. The proposed strategy based on synergic pore and defect engineering can pave the way for development of advanced metal oxides-based electrodes for (beyond) Li-ion batteries.

11.
Nanoscale ; 10(33): 15505-15512, 2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30090890

RESUMO

Despite their high-energy density, low cost and environmental friendliness, the commercial application of lithium-sulfur batteries (LSBs) has been plagued by their severe capacity decay during long-term cycling caused by polysulfide shuttling. Herein, we demonstrate a synergetic vacancy and heterostructure engineering strategy using a nitrogen-doped graphene/SnS2/TiO2 (denoted as NG/SnS2/TiO2) nanocomposite to enhance the electrochemical performance of LSBs. It is noted that plentiful sulfur vacancy (Vs) defects and nanosized heterojunctions are created on the NG/SnS2/TiO2 composite as proved using electron paramagnetic resonance, transmission electron microscopy and X-ray photoelectron spectroscopy, which can serve as strong adsorption and activation sites for polar polysulfide intermediates, prevent their dissolution/shuttling, and accelerate their redox reaction. The novel NG/SnS2/TiO2-S cathode delivers a high initial capacity of 1064 mA h g-1 at 0.5 C and a high capacity retention rate of 68% after 500 cycles at 0.5 C.

12.
Chemistry ; 24(50): 13246-13252, 2018 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-29926980

RESUMO

Hierarchically dual-mesoporous TiO2 microspheres have been synthesized by a solvothermal process in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4 ]) and diethylenetriamine (DETA) as co-templates. Secondary mesostructured defects in the hierarchical TiO2 microspheres produce oxygen vacancies, which not only significantly enhance photocatalytic activity in the degradation of methylene blue (1.7 times that with P25) and acetone (2.9 times that with P25), but are also beneficial for lithium storage. Moreover, we propose a mechanism to rationalize the role of this dual mesoporosity of the TiO2 microspheres in enhancing molecular diffusion, ion transportation, and electronic transitions.

13.
Chem Sci ; 9(21): 4730-4735, 2018 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-29910923

RESUMO

Single cell surface engineering provides the most efficient, non-genetic strategy to enhance cell stability. However, it remains a huge challenge to improve cell stability in complex artificial environments. Here, a soft biohybrid interfacial layer is fabricated on individual living-cell surfaces by their exposure to a suspension of gold nanoparticles and l-cysteine to form a protecting functional layer to which porous silica layers were bound yielding pores with a diameter of 3.9 nm. The living cells within the bilayered nanoshells maintained high viability (96 ± 2%) as demonstrated by agar plating, even after five cycles of simultaneous exposure to high temperature (40 °C), lyticase and UV light. Moreover, yeast cells encapsulated in bilayered nanoshells were more recyclable than native cells due to nutrient storage in the shell.

14.
Adv Mater ; 30(32): e1802173, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29947064

RESUMO

The homojunction of oxygen/metal vacancies and its interfacial n-p effect on the physiochemical properties are rarely reported. Interfacial n-p homojunctions of TiO2 are fabricated by directly decorating interfacial p-type titanium-defected TiO2 around n-type oxygen-defected TiO2 nanocrystals in amorphous-anatase homogeneous nanostructures. Experimental measurements and theoretical calculations on the cell lattice parameters show that the homojunction of oxygen and titanium vacancies changes the charge density of TiO2 ; a strong EPR signal caused by oxygen vacancies and an unreported strong titanium vacancies signal of 2D 1 H TQ-SQ MAS NMR are present. Amorphous-anatase TiO2 shows significant performance regarding the photogeneration current, photocatalysis, and energy storage, owing to interfacial n-type to p-type conductivity with high charge mobility and less structural confinement of amorphous clusters. A new "homojunction of oxygen and titanium vacancies" concept, characteristics, and mechanism are proposed at an atomic-/nanoscale to clarify the generation of oxygen vacancies and titanium vacancies as well as the interface electron transfer.

15.
Nanoscale ; 10(25): 11861-11868, 2018 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-29897083

RESUMO

Hierarchically porous carbon-supported sulfur material is widely used as a cathode for Li-S batteries because its large surface area and rich porous system provide high sulfur loading, resulting in high specific capacity with stable charge/discharge cycling performance. However, limited attention has been paid to whether the structure of hierarchical porous system affects the final electrochemical performance of Li-S/C batteries. Herein, we present hierarchically structured carbon (WSAC) with varied amounts of mesopores and micropores as a sulfur container for Li-S batteries. It is found that the relationship between electrochemical performance and percentage of microporous volume obeys a volcano distribution, which indicates that the volume percentage of microporous in the meso-microporous structure could be suitably tuned to achieve the desired electrochemical performance. Such S/hierarchically meso-microporous carbon (i.e., WSAC-8) with moderate microporous volume percentage (68.3%) shows high initial specific capacity (1375 mA h g-1) and stable charge/discharge performance (942.6 mA h g-1 after 200 cycles at 0.5C). In particular, WSAC-8 also presented superior capacity behavior at high rate capability, with final capacity as high as 800.1 and 758.7 mA h g-1 for 1C and 2C, respectively.

16.
Chem Asian J ; 13(12): 1609-1615, 2018 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-29635796

RESUMO

Hierarchical MoS2 @TiO2 heterojunctions were synthesized through a one-step hydrothermal method by using protonic titanate nanosheets as the precursor. The TiO2 nanosheets prevent the aggregation of MoS2 and promote the carrier transfer efficiency, and thus enhance the photocatalytic and electrocatalytic activity of the nanostructured MoS2 . The obtained MoS2 @TiO2 has significantly enhanced photocatalytic activity in the degradation of rhodamine B (over 5.2 times compared with pure MoS2 ) and acetone (over 2.8 times compared with pure MoS2 ). MoS2 @TiO2 is also beneficial for electrocatalytic hydrogen evolution (26 times compared with pure MoS2 , based on the cathodic current density). This work offers a promising way to prevent the self-aggregation of MoS2 and provides a new insight for the design of heterojunctions for materials with lattice mismatches.

17.
Chem Asian J ; 13(9): 1119-1123, 2018 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-29573170

RESUMO

Highly dispersed PtPd bimetallic nanocrystals with enhanced catalytic activity and stability were prepared by adjusting the interfacial wettability of the reaction solution on a commercial carbon support. This approach holds great promise for the development of high-performance and low-cost catalysts for practical applications.

18.
J Colloid Interface Sci ; 521: 1-10, 2018 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-29544116

RESUMO

We report three types of conducting polymers (CPs), polyaniline (PANI), polypyrrole (PPY) and poly (3,4-ethylenedioxythiophene) (PEDOT) to modify the surface of the CdS nanorods to probe their photocorrosion inhibition and photocatalytic hydrogen production. Various characterizations, such as high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and density function theory (DFT) calculations have been conducted to reveal the intrinsic structure of the as-constructed CPs@CdS (@ means CPs at the surface of CdS) core-shell nanorods. The results show that the PANI and PPY shells with abundant N and C atoms can significantly enhance the binding energy of Cd and S atoms on the surface of the CdS nanorods. However, there is no obvious enhancement of binding energy at the interface of the PEDOT shell and the CdS nanorods core. Therefore, PANI@CdS and PPY@CdS possess stronger driving force than PEDOT@CdS to inject the photogenerated holes in conducting polymer shells. As a result, the polyaniline (PANI) modified PANI@CdS core-shell nanorods demonstrate the most effectively enhanced hydrogen production rate of ∼9.7 mmol h-1 g-1 and effective photocorrosion inhibition in 30 h without deactivation under visible-light irradiation. The hydrogen production performance of PPY@CdS is not effectively promoted owing to the weak transmittance of light for the PPY shell. The PEDOT shell cannot improve the hydrogen production and stability property of the CdS nanorods. This work could shed some light on conducting polymers modifying metal sulfides nanostructures that is of inconceivable significance for effective photocorrosion inhibition and highly enhanced photocatalytic activities.

19.
Nanoscale ; 10(9): 4515-4522, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29460942

RESUMO

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has attracted much attention for solving the worldwide energy shortage and environmental pollution. In this work, for the first time we report oxygen self-doping of solvothermally synthesized g-C3N4 nanospheres with tunable electronic band structure via ambient air exposure for unprecedentedly enhanced photocatalytic performance. Various measurements, such as XPS, Mott-Schottky plots, and density functional theory (DFT) calculations reveal that such oxygen doping can tune the intrinsic electronic state and band structure of g-C3N4via the formation of C-O-C bond. Our results show that the oxygen doping content can be controlled by the copolymerization of the precursors. As a consequence, the oxygen doped g-C3N4 shows excellent photocatalytic performance, with an RhB photodegradation rate of 0.249 min-1 and a hydrogen evolution rate of 3174 µmol h-1 g-1, >35 times and ∼4 times higher than that of conventional thermally made pure g-C3N4 (0.007 min-1 and 846 µmol h-1 g-1, respectively) under visible light. Our work introduces a new route for the rational design and fabrication of doping modified g-C3N4 photocatalyst for efficient degradation of organic pollutants and H2 production.

20.
Nanoscale ; 10(7): 3112-3129, 2018 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-29393952

RESUMO

Inspired by the characteristics of cells in live organisms, new types of hybrids have been designed comprising live cells and abiotic materials having a variety of structures and functionalities. The major goal of these studies is to uncover hybridization approaches that promote cell stabilization and enable the introduction of new functions into living cells. Single-cells in nanoshells have great potential in a large number of applications including bioelectronics, cell protection, cell therapy, and biocatalysis. In this review, we discuss the results of investigations that have focused on the synthesis, structuration, functionalization, and applications of these single-cells in nanoshells. We describe synthesis methods to control the structural and functional features of single-cells in nanoshells, and further develop their applications in sustainable energy, environmental remediation, green biocatalysis, and smart cell therapy. Perceived limitations of single-cells in nanoshells have been also identified.

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