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1.
Nanomicro Lett ; 13(1): 201, 2021 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-34559322

RESUMO

Ultra-thin flexible films have attracted wide attention because of their excellent ductility and potential versatility. In particular, the energy-harvesting films (EHFs) have become a research hotspot because of the indispensability of power source in various devices. However, the design and fabrication of such films that can capture or transform different types of energy from environments for multiple usages remains a challenge. Herein, the multifunctional flexible EHFs with effective electro-/photo-thermal abilities are proposed by successive spraying Ag microparticles and MXene suspension between on waterborne polyurethane films, supplemented by a hot-pressing. The optimal coherent film exhibits a high electrical conductivity (1.17×104 S m-1), excellent Joule heating performance (121.3 °C) at 2 V, and outstanding photo-thermal performance (66.2 °C within 70 s under 100 mW cm-1). In addition, the EHFs-based single-electrode triboelectric nanogenerators (TENG) give short-circuit transferred charge of 38.9 nC, open circuit voltage of 114.7 V, and short circuit current of 0.82 µA. More interestingly, the output voltage of TENG can be further increased via constructing the double triboelectrification layers. The comprehensive ability for harvesting various energies of the EHFs promises their potential to satisfy the corresponding requirements.

2.
Chem Commun (Camb) ; 57(75): 9610-9613, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34546262

RESUMO

In situ Raman and electrochemical results reveal that Na+ adsorbs on the surface/defective sites of N/P-HCNF and inserts randomly into its turbostratic nanodomains in the dilute state without a staged formation, which can facilitate fast Na+ diffusion kinetics for efficient sodium storage.

3.
J Colloid Interface Sci ; 607(Pt 2): 1103-1108, 2021 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-34571297

RESUMO

Titanium niobate (TiNb2O7, TNO) possesses attractive discharge voltage and reversibility, which is considered to be an ideal anode material of lithium ion battery (LIB). However, its rate capability is strictly limited by their poor conductivity. To improve this issue faced by traditional TNO electrodes, a hierarchical conductive optimization strategy has been proposed and fabricated by a facile spray drying approach. For the construction, TiNb2O7@ultrathin carbon layer (TNO@C) is entangled into carbon nanotubes network to synthesize a highly conductive porous TNO@C/CNTs microsphere. This ultrathin carbon layer and evenly intertwined carbon nanotubes can ensure the superior charge transfer pathway, facilitating the transportation of electrons and Li ions. Additionally, CNTs can provide robust mechanical strength framework, beneficial to the structural stability of composite microspheres. As expected, the TNO@C/CNTs exhibits elevated conductivity and cyclic durability with charge capacities of 343.3 mAh·g-1 at 0.25 C after 300 cycles and 274.9 mAh·g-1 at 10 C after 1000 cycles. This study intends to explore the effect of the attached carbon materials on the TNO-based electrode conductivity and LIBs performances.

4.
ACS Appl Mater Interfaces ; 13(33): 39126-39134, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34383476

RESUMO

The usage of exogenous antioxidant materials to relieve oxidative stress offers an important strategy for the therapy of oxidative stress-induced injuries. However, the fabrication processes toward the antioxidant materials usually require the involvement of extra metal ions and organic agents, as well as sophisticated purification steps, which might cause tremendous environmental stress and induce unpredictable side effects in vivo. To address these issues, herein, we proposed a novel strategy to fabricate green nanoparticles for efficiently modulating oxidative stress, which was facilely prepared from tea polyphenol extracts (originated from green tea) via a green enzymatic polymerization-based chemistry method. The resulting nanoparticles possessed a uniform spherical morphology and good stability in water and biomedium and demonstrated excellent radical scavenging properties. These nanoparticle scavengers could effectively prevent intracellular oxidative damage, accelerate wound recovery, and protect the kidneys from reactive oxygen species damaging in the acute kidney injury model. We hope this work will inspire the further development of more types of green nanoparticles for antioxidant therapies via similar synthetic strategies using green biomass materials.


Assuntos
Injúria Renal Aguda/prevenção & controle , Antioxidantes/química , Nanopartículas/química , Estresse Oxidativo/efeitos dos fármacos , Polifenóis/química , Chá/química , Células 3T3 , Células A549 , Animais , Antioxidantes/farmacologia , Catecóis/química , Sobrevivência Celular/efeitos dos fármacos , Feminino , Sequestradores de Radicais Livres/metabolismo , Química Verde , Peroxidase do Rábano Silvestre/química , Células Endoteliais da Veia Umbilical Humana , Humanos , Peróxido de Hidrogênio/química , Camundongos , Espécies Reativas de Oxigênio/metabolismo , Nanomedicina Teranóstica , Cicatrização/efeitos dos fármacos
5.
Angew Chem Int Ed Engl ; 60(41): 22411-22416, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34347339

RESUMO

We report the synthesis and structure of tertiary chiral nanostructures with 100 % optical purity. A novel synthetic strategy, using chiral reducing agent, R and S-BINAPCuBH4 (BINAP is 2,2'-Bis(diphenylphosphino)-1,1'-binaphthyl), is developed to access to atomically precise, intrinsically chiral [Au7 Ag6 Cu2 (R- or S-BINAP)3 (SCH2 Ph)6 ]SbF6 nanoclusters in one-pot synthesis. The clusters represent the first tri-metallic superatoms with inherent chirality and fair stability. Both metal distribution (primary) and ligand arrangement (secondary) of the enantiomers exhibited perfect mirror images, and unprecedentedly, the self-assembly driven by the C-H⋅⋅⋅F interaction between the phenyl groups of the superatom moieties and SbF6 - anions induced the formation of bio-mimic left- and right-handed helices, achieving the tertiary chiral nanostructures. DFT calculations revealed the connections between the molecular details and chiral optical activity.

6.
Chem Commun (Camb) ; 2021 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-34318801

RESUMO

The introduction of oxygen vacancies (OVs) into Nb2O5 can not only provide more active sites for lithium storage but also change the electronic structure of Nb2O5 to boost electron/ion transport kinetics. Consequently, the defective Nb2O5-x exhibits high lithium storage capacity, superior rate capability, and cycling stability.

7.
Artigo em Inglês | MEDLINE | ID: mdl-34101415

RESUMO

Flexible and multifunctional textiles have potential applications in self-cleaning and portable electronic product applications, but the current problem that needs to be solved is to maintain their inherent breathability and flexibility while expanding other functional applications. Herein, we adopt the layer-by-layer assembly method to develop a multifunctional textile with superior asymmetric superhydrophobicity, excellent electromagnetic interference (EMI) shielding, outstanding photothermal conversion, and solar water evaporation. The synergistic effect of SiO2 nanoparticles/poly(dimethylsiloxane) (PDMS) and 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES) endows the textile with a water contact angle of 160°. MXene provides high conductivity (1200 S/m) and EMI shielding effects (36 dB) for multifunctional textiles. In addition, the multifunctional textile exhibits excellent photothermal conversion, and satisfactory solar water evaporation efficiency (80%) and rate (1.22 kg/(m2 h)) under 1 sun. Therefore, the prepared multifunctional textile has great potential in multiscene applications.

8.
J Am Chem Soc ; 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34133156

RESUMO

Wide-bandgap semiconductors exhibiting a bandgap of ∼1.7-1.9 eV have generated great interest recently due to their important applications in tandem solar cells as top cells and emerging indoor photovoltaics. However, concerns about the stability and toxicity especially in indoor application limit the choice of these materials. Here we report a new member of this family, germanium monosulfide (GeS); this material displays a wide bandgap of 1.7 eV, nontoxic and earth-abundant constituents, and high stability. We find that the little success of GeS solar cells to date is primarily attributed to the challenge in fabricating high-quality polycrystalline GeS films, wherein the high thermal expansion coefficient (α = 3.1 × 10-5 K-1) combined with high crystallization temperature (375 °C) of GeS induces large tensile strain in the GeS film that peels off GeS from the substrate. By introducing a high-α buffer layer between GeS and substrate, we achieve a high-quality polycrystalline GeS thin film that compactly adheres to substrate with no voids. Solar cells fabricated by these GeS films show a power conversion efficiency of 1.36% under AM 1.5G illumination (100 mW cm-2). The unencapsulated devices are stable when stored in ambient atmosphere for 1500 h. Their efficiencies further increase to 3.6% under indoor illumination of 1000 lux.

10.
Nanomicro Lett ; 13(1): 64, 2021 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-34138311

RESUMO

In recently years, high-performance wearable strain sensors have attracted great attention in academic and industrial. Herein, a conductive polymer composite of electrospun thermoplastic polyurethane (TPU) fibrous film matrix-embedded carbon black (CB) particles with adjustable scaffold network was fabricated for high-sensitive strain sensor. This work indicated the influence of stereoscopic scaffold network structure built under various rotating speeds of collection device in electrospinning process on the electrical response of TPU/CB strain sensor. This structure makes the sensor exhibit combined characters of high sensitivity under stretching strain (gauge factor of 8962.7 at 155% strain), fast response time (60 ms), outstanding stability and durability (> 10,000 cycles) and a widely workable stretching range (0-160%). This high-performance, wearable, flexible strain sensor has a broad vision of application such as intelligent terminals, electrical skins, voice measurement and human motion monitoring. Moreover, a theoretical approach was used to analyze mechanical property and a model based on tunneling theory was modified to describe the relative change of resistance upon the applied strain. Meanwhile, two equations based from this model were first proposed and offered an effective but simple approach to analyze the change of number of conductive paths and distance of adjacent conductive particles.

11.
Nat Commun ; 12(1): 2608, 2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-33972558

RESUMO

The oxygen evolution reaction (OER) is the bottleneck that limits the energy efficiency of water-splitting. The process involves four electrons' transfer and the generation of triplet state O2 from singlet state species (OH- or H2O). Recently, explicit spin selection was described as a possible way to promote OER in alkaline conditions, but the specific spin-polarized kinetics remains unclear. Here, we report that by using ferromagnetic ordered catalysts as the spin polarizer for spin selection under a constant magnetic field, the OER can be enhanced. However, it does not applicable to non-ferromagnetic catalysts. We found that the spin polarization occurs at the first electron transfer step in OER, where coherent spin exchange happens between the ferromagnetic catalyst and the adsorbed oxygen species with fast kinetics, under the principle of spin angular momentum conservation. In the next three electron transfer steps, as the adsorbed O species adopt fixed spin direction, the OER electrons need to follow the Hund rule and Pauling exclusion principle, thus to carry out spin polarization spontaneously and finally lead to the generation of triplet state O2. Here, we showcase spin-polarized kinetics of oxygen evolution reaction, which gives references in the understanding and design of spin-dependent catalysts.

12.
Artigo em Inglês | MEDLINE | ID: mdl-34018300

RESUMO

A photocharge/discharge strategy is proposed to initiate the WO3 photoelectrode and suppress the main charge recombination, which remarkably improves the photoelectrochemical (PEC) performance. The photocharged WO3 surrounded by a 8-10 nm overlayer and oxygen vacancies could be operated more than 25 cycles with 50 h durability without significant decay on PEC activity. A photocharged WO3 /CuO photoanode exhibits an outstanding photocurrent of 3.2 mA cm-2 at 1.23 VRHE with a low onset potential of 0.6 VRHE , which is one of the best performances of p-n heterojunction structure. Using nonadiabatic molecular dynamics combined with time-domain DFT, we clarify the prolonged charge carrier lifetime of photocharged WO3 , as well as how electronic systems of photocharged WO3 /CuO semiconductors enable the effective photoinduced electrons transfer from WO3 into CuO. This work provides a feasible route to address excessive defects existed in photoelectrodes without causing extra recombination.

13.
Artigo em Inglês | MEDLINE | ID: mdl-33840190

RESUMO

Low acid endurance of layered double hydroxides (LDHs) limits their uranium(VI) [U(VI)] adsorption capability from harsh industrial wastewater. Here, we demonstrate magnesium-cobalt LDHs (Mg-Co LDHs) anchored in situ onto the pore channel of dendritic fibrous nanosilica (DFNS) via an interface-constrained strategy. The synergy of Mg-Co LDHs and DFNS not only improves the endurance of the Mg-Co LDH under harsh acidic conditions but also increases the number of active sites of DFNS. Thus, DFNS@Mg-Co LDH shows a high U(VI) uptake capacity (1143 mg g-1) at pH = 3 and C0 = 598.7 mg L-1, which is about 4.8-fold higher than that of pristine DFNS. The DFNS@Mg-Co LDH exhibits excellent U(VI) uptake in various background water circumstances due to its acid endurance and highly selective adsorption. This interface-constrained strategy provides LDH materials with durability under extremely acidic conditions along with a high adsorption capacity, which is promising for uranium capture from various water fields.

14.
Angew Chem Int Ed Engl ; 60(23): 12897-12903, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33719174

RESUMO

Surface ligands play critical roles in determining the surface properties of metal clusters. However, modulating the properties and controlling the surface structure of clusters through surface-capping-agent displacement is challenging. Herein, [Ag14 (SPh(CF3 )2 )12 (PPh3 )4 (DMF)4 ] (Ag14 -DMF; DMF=N,N-dimethylformamide), with weakly coordinated DMF ligands on surface silver sites, was synthesized by a mixed-ligands strategy. Owing to the high surface reactivity of Ag14 -DMF, the surface ligands are labile, easily dissociated or exchanged by other ligands. Based on the enhanced surface reactivity, easy modulation of the optical properties of Ag14 by reversible "on-off" DMF ligation was realized. When chiral amines were introduced to as-prepared products, all eight surface ligands were replaced by amines and the racemic Ag14 clusters were converted to optically pure homochiral Ag14 clusters as evidenced by circular dichroism (CD) activity and single-crystal X-ray diffraction (SCXRD). This work provides a new insight into modulation of the optical properties of metal clusters and atomically precise homochiral clusters for specific applications are obtained.

15.
Artigo em Inglês | MEDLINE | ID: mdl-33538165

RESUMO

A solar steam generation method has been widely investigated as a sustainable method to achieve seawater desalination and sewage treatment. However, oil pollutants are usually emitted in real seawater or wastewaters, which can cause serious fouling problems to disturb the solar evaporation performance. In this work, a mussel-inspired, low-cost, polydopamine-filled cellulose aerogel (PDA-CA) has been rationally designed and fabricated with both superhydrophilicity and underwater superoleophobicity. The resulting PDA-CA device could also achieve a high solar evaporation rate of 1.36 kg m-1 h-1 with an 86% solar energy utilize efficiency under 1 sun illumination. In addition, the PDA-CA not only exhibited promising antifouling capacity for long-term water evaporation but also engaged in the effective adsorption of organic dye contaminants. These promising features of PDA-CA may offer new opportunities for developing multifunctional photothermal devices for solar-driven water remediation.

16.
Chem Asian J ; 15(22): 3737-3751, 2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-32997441

RESUMO

Rechargeable zinc-air batteries (ZABs) are considered as one of the most promising electrochemical energy devices due to their various unique advantages. Oxygen electrocatalysis, involving the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), determines the overall performance of zinc-air batteries. Therefore, the development of highly efficient bifunctional ORR/OER catalysts is critical for the large-scale application of ZABs. Carbon-based nanomaterials have been widely reported to be efficient electrocatalysts toward both ORR and OER. The enhanced activity of these electrocatalysts are usually attributed to different doping defects, synergistic effects and even the intrinsic carbon defects. Herein, an overview of the defect engineering in carbon-based electrocatalysts for ORR and OER is provided. The different types of intrinsic carbon defects and strategies for the generation of other defects in carbon-based electrocatalysts are presented. The interaction of heteroatoms doped carbon and transition metals (TMs) is also explored. In the end, the existing challenges and future perspectives on defect engineering are discussed.

17.
Adv Sci (Weinh) ; 7(16): 2001013, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32832357

RESUMO

Environmentally benign and potentially cost-effective Sb2Se3 solar cells have drawn much attention by continuously achieving new efficiency records. This article reports a compatible strategy to enhance the efficiency of planar n-i-p Sb2Se3 solar cells through Sb2Se3 surface modification and an architecture with oriented 1D van der Waals material, trigonal selenium (t-Se). A seed layer assisted successive close spaced sublimation (CSS) is developed to fabricate highly crystalline Sb2Se3 absorbers. It is found that the Sb2Se3 absorber exhibits a Se-deficient surface and negative surface band bending. Reactive Se is innovatively introduced to compensate the surface Se deficiency and form an (101) oriented 1D t-Se interlayer. The p-type t-Se layer promotes a favored band alignment and band bending at the Sb2Se3/t-Se interface, and functionally works as a surface passivation and hole transport material, which significantly suppresses interface recombination and enhances carrier extraction efficiency. An efficiency of 7.45% is obtained in a planar Sb2Se3 solar cell in superstrate n-i-p configuration, which is the highest efficiency for planar Sb2Se3 solar cells prepared by CSS. The all-inorganic Sb2Se3 solar cell with t-Se shows superb stability, retaining ≈98% of the initial efficiency after 40 days storage in open air without encapsulation.

18.
Biomater Sci ; 8(18): 4940-4950, 2020 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-32807998

RESUMO

Polydopamine (PDA) is the most typical kind of synthetic melanin, which possesses interesting properties such as antioxidation, photoprotection, metal chelation, and energy dissipation. Over the past few years, PDA has been successfully synthesized via polymerization methods and has demonstrated excellent free radical scavenging ability. The related applications have been rapidly expanded to include sunscreens, anti-inflammatory treatment, and composite material fabrication. Despite great progress, the comprehensive mechanisms of its free radical scavenging behaviors are not fully understood. This article strives to summarize the possible mechanisms, established antioxidant regulation methods and the related biomedical applications of PDA free radical scavengers. We believe this paper can provide insight into the current PDA scavenging systems and offer inspiration towards the design of new melanin-inspired scavengers with a broad range of biomedical applications.


Assuntos
Sequestradores de Radicais Livres , Polímeros , Sequestradores de Radicais Livres/farmacologia , Indóis , Polimerização
19.
ACS Appl Mater Interfaces ; 12(37): 41950-41959, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32809789

RESUMO

Effectively restraining random fluctuation of layer thickness (RFT) during the thin-film epitaxy plays an essential part in improving the quality of low-dimensional materials for device application. While it is already challenging to obtain an ideal growth condition for thickness control, the tangle of RFT with interfacial problems makes it even more difficult to guarantee the properties of heterostructures and the performance of devices. In our research, the RFT of potential barriers and wells within a semiconductor multilayer is demonstrated to correlate with the interfacial grading effect (IFG) and to affect the band offset strongly. Then, the synergetic effect of RFT and IFG that serves as the first domino is shown to impact the subband structure and the electron transport successively. On the basis of an investigation of a quantum cascade structure, statistical results indicate a normal distribution of RFT with a standard deviation of about 1 Å and an extreme value of 3 Å (about one monolayer) for all the layers within 38 cascade periods. The "seemingly negligible" RFT could actually reduce the conduction band offset for tens to hundreds of meV and alter the subband gaps at a rate of 40 meV/monolayer at most. Furthermore, the dependence of different subband gaps on the barrier/well thickness differs from one another. In addition, the distribution of wave function could also be regulated dramatically by RFT to change the type of electron transition and thus the carrier lifetime. Further impacts of RFT and the RFT-modulated subband alignment on electron transport result in two different mechanisms (injection-dominant and extraction-dominant) of electron population inversion (PI), which is manifested by comparatively discussing the results of in situ electron holography and macro performances.

20.
Small ; 16(39): e2001027, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32856390

RESUMO

Lithium-sulfur (Li-S) batteries with a high energy density and long lifespan are considered as promising candidates for next-generation electrochemical energy-storage devices. However, the sluggish redox kinetics of electrochemistry and high solubility of polysulfide during cycling render insufficient sulfur utilization and poor cycling stability. Herein, a facile, template-free procedure based on controlled pyrolysis of polydopamine vesicles is described to prepare N-doped porous carbon cages (NHSC) as a new sulfur host, which significantly improves both the sulfur utilization and cycling stability. As NHSC shows a high pore volume, continuous electron and ion transport paths, and good catalytic activity, encapsulation of S nanoparticles into NHSC endows the resulting S@NHSC electrode with a good energy storage capacity and exceptionally high electrochemical stability. Consequently, a Li-S cell with the S@NHSC as the cathode achieves a high initial capacity of 1280.7 mAh g-1 , and cycling stability over 500 cycles with the capacity decay as low as 0.0373% per cycle.

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