Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
1.
J Colloid Interface Sci ; 679(Pt B): 383-390, 2024 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-39461127

RESUMO

The insufficient solar light response ability of the photocatalyst, rapid recombination of interface charges, and lack of active sites significantly inhibit the efficiency of photocatalytic CO2 reduction. Addressing these challenges simultaneously is a very challenging task. Herein, an interface engineering coupled surface polarization strategy is proposed to optimize the CO2 photoreduction performance. The copper tetracarboxyphenylporphyrin (CuTCPP) modified BiOBr/Bi19S27Br3 (BBS) heterostructure was developed. The built-in electric field formed between BiOBr and Bi19S27Br3 interfaces induces the effective interfacial charge separation, while the surface polarization of CuTCPP induces the transfer of electrons from the conduction band (CB) of BBS to the CB of CuTCPP. Benefiting from this unique configuration and abundant active sites in CuTCPP, greatly improved photocatalytic CO2 reduction performance can be realized. Without adding cocatalysts and sacrificial agents, the optimized CO generation performance of CuTCPP-BiOBr/Bi19S27Br3 (BBS-CT) is 3.5 times higher than that of BBS. This work provides valuable insights of interface engineering coupled surface polarization strategy for collaborative improve the photocatalytic CO2 reduction performance.

2.
Front Endocrinol (Lausanne) ; 15: 1411657, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39224125

RESUMO

Objective: The aim of this study is to assess the effectiveness of foot skin protection technology in elderly patients with diabetic peripheral neuropathy. Methods: The foot skin protection technology was developed based on a comprehensive literature review and preliminary research conducted by our research team. Subsequently, 88 elderly patients with diabetic peripheral neuropathy and experiencing foot skin problems were recruited from two community health service centers in Shanghai. Using a random number table, the participants were randomly assigned to either the control group or the experimental group. Patients in the experimental group received foot skin protection technology interventions, while those in the control group received standard community nursing guidance for a duration of 3 months. The incidence, severity, and discomfort associated with foot skin problems were evaluated before and after the intervention period in both groups. Results: The incidence, severity, and discomfort of foot skin problems notably reduced in the experimental group (all P< 0.05). Conclusion: The foot skin protection technology demonstrates significant potential in enhancing foot skin condition.


Assuntos
Pé Diabético , Neuropatias Diabéticas , Humanos , Masculino , Idoso , Feminino , Neuropatias Diabéticas/prevenção & controle , Pé Diabético/prevenção & controle , Pessoa de Meia-Idade , China/epidemiologia , , Idoso de 80 Anos ou mais
3.
Poult Sci ; 103(2): 103270, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38056054

RESUMO

This experiment aims to evaluate the effect of bile acids (BAs) in alleviating fatty liver disease induced by a high-fat diet (HFD) in broilers, and the modulation of the gut microbiota involved in this process. A total of 192 one-day-old Arbor Acres (AA) commercial male broilers were randomly divided into 4 groups and treated with the following diet: a basal-fat diet (BFD), a basal-fat diet plus bile acids (BFD + BAs), an HFD, and a high-fat diet plus bile acids (HFD + BAs). Bile acids were supplemented at the early growth stage (3-7 d), middle stage (17-21 d), and late stage (31-35 d). Results showed that BAs treatment had a significant effect on body weight on 14 d and 35 d, and increased the breast muscle weight and its index, but decreased the liver weight and abdominal fat weight on 35 d (P < 0.05). The supplementation of BAs significantly improved the serum lipid profile and decreased the level of triglycerides (TG), total cholesterol (TCHO), and nonesterified fatty acids (NEFA) on 35 d (P < 0.05). Dietary BAs supplementation significantly alleviated the hepatic TG deposition induced by HFD (P < 0.05), which was accompanied by upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and lipoprotein lipase (LPL) gene expression (P < 0.05). Moreover, the expression levels of hepatic gene adipose triglyceride lipase (ATGL), peroxisome proliferator-activated receptor α (PPARα), and apolipoprotein B (APOB) were greatly increased by BAs treatment. The analysis of 16S rRNA sequencing showed that the microbial diversity of the cecal digesta was increased by BAs in broilers with elevated abundances of Firmicutes, Lactobacillus, Anaerostipes, Sellimonas, and CHKCI002 and decreased abundances of Barnesiella and Akkermansia genus (P < 0.05). Hepatic TG content was positively correlated with the abundance of Oscillospiraceae, but it was negatively correlated with the abundance of Lactobacillus in cecal digesta (P < 0.05). These results indicate that dietary BAs can improve growth performance and alleviate fatty liver disease induced by an HFD via modulating gut microbiota in broilers.


Assuntos
Microbioma Gastrointestinal , Hepatopatia Gordurosa não Alcoólica , Masculino , Animais , Dieta Hiperlipídica/efeitos adversos , Dieta Hiperlipídica/veterinária , Galinhas/fisiologia , Ácidos e Sais Biliares/metabolismo , RNA Ribossômico 16S , Fígado/metabolismo , Hepatopatia Gordurosa não Alcoólica/veterinária , Suplementos Nutricionais/análise , Triglicerídeos/metabolismo
4.
Chemosphere ; 344: 140347, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37793552

RESUMO

Photocatalytic degradation of pollutants is considered a promising approach for wastewater treatment, but is hampered by low efficiency and limited understanding of degradation pathways. A novel oxygen-doped porous g-C3N4/oxygen vacancies-rich BiOCl (OCN/OVBOC) heterostructure was prepared for photocatalytic degradation of bisphenol A (BPA). The synergistic defect and doping engineering favor the formation of strong bonded interface for S-scheme mechanism. Among them, 0.3 OCN/OVBOC showed the most excellent degradation rate, which was 8 times and 4 times higher than that of pure g-C3N4 and BiOCl, respectively. This excellent performance is mainly attributed to the significantly enhanced charge separation via strong bonded interface and redox capability of the S-scheme heterojunction structure, by tuning the coordination excitation and electron localization of the catalyst via O doping and vacancies. This work provides important insights into the role of synergistic defect and doping engineering in facilitating the formation of strong bonded S-scheme heterojunction and ultimately sheds new light on the design of efficient photocatalysts.


Assuntos
Elétrons , Poluentes Ambientais , Oxigênio , Porosidade
5.
Phys Chem Chem Phys ; 25(27): 17907-17911, 2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37376900

RESUMO

Quasi-one-dimensional materials are usually characterized by optical response spectroscopy methods, which show significant polarization dependence. Herein, we report a systematical investigation of polarized Raman scattering on the (110) crystal surface of the layered (TaSe4)2I compound. Taking into account group theory analysis of the crystal structure and the Raman tensor transformation technique, the vibrational mode of the Raman peaks can be differentiated by the angular dependence of the Raman peak intensity in parallel and vertical polarization Raman scattering tests. Moreover, density functional perturbation theory (DFPT) calculation confirmed the form of the Raman tensor of the (110) crystal surface, which was consistent with the result of the Raman tensor transformation technique, and the Raman spectrum and phonon dispersion curve calculations were also performed based on the Vienna ab initio simulation package (VASP). This new method provides useful insight for accurately identifying the lattice vibration behavior in new 2D layered structures.

6.
Adv Mater ; 35(30): e2205346, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36807321

RESUMO

The importance of catalysts today as workhorses in most modern industrial fields cannot be downplayed. As a result, rational design and engineering of targeted catalysts have emerged as key objectives and are dependent on in-depth understanding of complex catalytic dynamics. Synchrotron radiation (SR) light sources with rich advanced experimental methods are being recognized as a comprehensive characterization platform, which can draw a full picture on such multiparameter-involved catalysis under actual working conditions. Herein, the recent progress of catalytic dynamics process studied by the means of various SR techniques is summarized. In particular, SR-based spectroscopic, scattering, and imaging investigations on true catalysts are first introduced with the potential of in situ and operando characterizations. Apparently, the limitations from single SR technique naturally prompt a simple combination of SR techniques to better understand the whole catalysis process. Moreover, the discrepancies among various online testing facilities and batches of samples, along with random/systematic errors introduced by traditional intermittent/asynchronous measurement make it imperative to develop more prolific systems, complementary of multiple SR techniques for deep probing of dynamic catalytic processes. It is believed that the booming new light sources can further enrich the current multiple SR techniques, and thus may realize the true visualization on future catalytic dynamic processes.

7.
Adv Mater ; 34(50): e2207691, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36193772

RESUMO

CO2 electrocatalytic reduction (CO2 ER) to multicarbon (C2+ ) products is heavily pursued because of their commercial values, and the efficiency and selectivity have both attracted tremendous attention. A flow-cell is a device configuration that can greatly enhance the conversion efficiency but requires catalysts to possess high electrical conductivity and gas permeability; meanwhile, the catalysts should enable the reaction pathway to specific products. Herein, it is reported that V-doped Cu2 Se nanotubes with a hierarchical structure can be perfectly compatible with flow-cells and fulfil such a task, achieving CO2 electroreduction to ethanol with high efficiency and selectivity. As revealed by the experimental characterization and theoretical calculation, the substitutional vanadium doping alters the local charge distribution of Cu2 Se and diversifies the active sites. The unique active sites promote the formation of bridge *COB and its further hydrogenation to *COH, and, as such, the subsequent coupling of *COH and *COL eventually generates ethanol. As a result, the optimal Cu1.22 V0.19 Se nanotubes can electrocatalyze CO2 to ethanol with a Faradaic efficiency of 68.3% and a partial current density of -207.9 mA cm-2 for the single liquid product of ethanol at -0.8 V in a flow-cell. This work provides insights into the materials design for steering the reaction pathway toward C2+ products, and opens an avenue for flow-cell CO2 ER toward a single C2+ liquid fuel.

8.
Angew Chem Int Ed Engl ; 61(36): e202209268, 2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-35833916

RESUMO

It is highly desired yet challenging to steer the CO2 electroreduction reaction (CO2 ER) toward ethanol with high selectivity, for which the evolution of reaction intermediates on catalytically active sites holds the key. Herein, we report that K doping in Cu2 Se nanosheets array on Cu foam serves as a versatile way to tune the interaction between Cu sites and reaction intermediates in CO2 ER, enabling highly selective production of ethanol. As revealed by characterization and simulation, the electron transfer from K to Se can stabilize CuI species which facilitate the adsorption of linear *COL and bridge *COB intermediates to promote C-C coupling during CO2 ER. As a result, the optimized K11.2% -Cu2 Se nanosheets array can catalyze CO2 ER to ethanol as a single liquid product with high selectivity in a potential area from -0.6 to -1.2 V. Notably, it offers a Faradaic efficiency of 70.3 % for ethanol production at -0.8 V with as is stable for 130 h.

9.
J Hazard Mater ; 437: 129327, 2022 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-35709622

RESUMO

Metal nanostructures with high atom utilization, abundant active sites, and special electron structures should be beneficial to the electrochemical monitoring of hydroquinone (HQ), a highly toxic environmental pollutant. However, traditional nanostructures, especially non-noble metals generally suffer from severe aggregation, or consist of a mixture of nanoparticles and nanoclusters, resulting in low detection sensitivity. Herein, we precisely control the size of Mo-based nanostructures spanning four scales (viz. Mo2C nanoparticles, Mo2C nanodots, Mo nanoclusters and Mo single atoms) anchored on N, P, O co-doped carbon support. The detection sensitivity of four samples toward the HQ follows the orders of Mo single atoms>Mo2C nanodots>Mo nanoclusters>Mo2C nanoparticles. The catalytic ability of four catalysts is investigated, also showing the same order. The supported Mo single atoms show superior electro-sensing performance for HQ with wide linear range (0.02-200 µM) and low detection limit (0.005 µM), surpassing most previously reported catalysts. Moreover, the coexistence of dihydroxybenzene isomers of catechol (CC) and resorcinol (RC) does not interfere with the detection of HQ on the Mo single-atom sensor. This work opens up a polyoxometalate-based confinement pyrolysis approach to constructing ultrafine metal-based nanostructures spanning multiple-scales for efficient electrochemical applications.


Assuntos
Hidroquinonas , Nanoestruturas , Ânions , Carbono/química , Eletrodos , Polieletrólitos , Pirólise
10.
Adv Mater ; 34(28): e2202367, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35522089

RESUMO

Light utilization largely governs the performance of CO2 photoconversion, whereas most of the materials that are implemented in such an application are restricted in a narrow spectral absorption range. Plasmonic metamaterials with a designable regular pattern and facile tunability are excellent candidates for maximizing light absorption to generate substantial hot electrons and thermal energy. Herein, a concept of coupling a Au-based stacked plasmonic metamaterial with single Cu atoms in alloy, as light absorber and catalytic sites, respectively, is reported for gas-phase light-driven catalytic CO2 hydrogenation. The metamaterial structure works in a broad spectral range (370-1040 nm) to generate high surface temperature for photothermal catalysis, and also induces strong localized electric field in favor of transfer of hot electrons and reduced energy barrier in CO2 hydrogenation. This work unravels the significant role of a strong localized electric field in photothermal catalysis and demonstrates a scalable fabrication approach to light-driven catalysts based on plasmonic metamaterials.

12.
Mater Horiz ; 8(2): 612-618, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34821278

RESUMO

Cocatalyst design is a key approach to acquire high solar-energy conversion efficiency for photocatalytic hydrogen evolution. Here a new in situ vapor-phase (ISVP) growth method is developed to construct the cocatalyst of 2D PtS nanorectangles (a length of ∼7 nm, a width of ∼5 nm) on the surface of g-C3N4 nanosheets. The 2D PtS nanorectangles/g-C3N4 nanosheets (PtS/CN) show an unusual metal sulfide-support interaction (MSSI), which is evidenced by atomic resolution HAADF-STEM, synchrotron-based GIXRD, XPS and DFT calculations. The effect of MSSI contributes to the optimization of geometrical structure and energy-band structure, acceleration of charge transfer, and reduction of hydrogen adsorption free energy of PtS/CN, thus yielding excellent stability and an ultrahigh photocatalytic H2 evolution rate of 1072.6 µmol h-1 (an apparent quantum efficiency of 45.7% at 420 nm), up to 13.3 and 1532.3 times by contrast with that of Pt nanoparticles/g-C3N4 nanosheets and g-C3N4 nanosheets, respectively. This work will provide a new platform for designing high-efficiency photocatalysts for sunlight-driven hydrogen generation.

13.
J Am Chem Soc ; 143(43): 18103-18113, 2021 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-34606266

RESUMO

Reducing the lateral scale of two-dimensional (2D) materials to one-dimensional (1D) has attracted substantial research interest not only to achieve competitive electronic applications but also for the exploration of fundamental physical properties. Controllable synthesis of high-quality 1D nanoribbons (NRs) is thus highly desirable and essential for further study. Here, we report the implementation of supervised machine learning (ML) for the chemical vapor deposition (CVD) synthesis of high-quality quasi-1D few-layered WTe2 NRs. Feature importance analysis indicates that H2 gas flow rate has a profound influence on the formation of WTe2, and the source ratio governs the sample morphology. Notably, the growth mechanism of 1T' few-layered WTe2 NRs is further proposed, which provides new insights for the growth of intriguing 2D and 1D tellurides and may inspire the growth strategies for other 1D nanostructures. Our findings suggest the effectiveness and capability of ML in guiding the synthesis of 1D nanostructures, opening up new opportunities for intelligent materials development.

14.
Small ; 16(42): e2003302, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32969149

RESUMO

The relatively high recombination rate of charges remains the most critical limiting factor for solar-driven water splitting for hydrogen generation. Herein, a tandem 0D/2D/2D NbS2 quantum dot/Nb2 O5 nanosheet/g-C3 N4 flake (NSNOCN) system is designed. Owing to the unique spatial-arrangement and elaborate morphology of 0D NbS2 , 2D Nb2 O5 , and 2D g-C3 N4 in the newly designed NSNOCN, plenty of spatial charge-transfer cascades from g-C3 N4 to NbS2 via Nb2 O5 are formed to accelerate separation and transfer of charges significantly, thus contributing to a high photocatalytic H2 generation rate of 13.99 mmol h-1 g-1 (an apparent quantum efficiency of 10.8% at 420 nm), up to 107.6 and 43.7 times by contrast with that of g-C3 N4 and Nb2 O5 , respectively. This work can provide a new platform in the design of artificial photocatalytic systems with high charge-transfer efficiency.

15.
Biosens Bioelectron ; 165: 112373, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32729505

RESUMO

Herein, size-controllable molybdenum carbide nanoparticles (Mo2C NPs) encapsulated by N, P-codoped carbon shells which simultaneously wrapping on the surface of carbon nanotube (Mo2C@NPC/CNT) is synthesized through a molecular-scale cage-confinement pyrolysis route. Such confinement achieves a good coating and protection of Mo2C and the effective control over the size of Mo2C NPs ranging from 2.5 to 10 nm facilitates a rational investigation into their electrochemical sensor behavior at nanometer scales. The optimized structure consisting of Mo2C nanoparticles with size of ~5 nm showed an outstanding electrochemical response toward dopamine (DA) and acetaminophen (AC) with detection limits (S/N = 3) of 0.008 µM for AC and 0.01 µM for DA.


Assuntos
Técnicas Biossensoriais , Nanopartículas , Técnicas Eletroquímicas , Eletrodos , Molibdênio , Pirólise
16.
Nat Commun ; 11(1): 3729, 2020 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-32709904

RESUMO

Two-dimensional (2D) magnets with intrinsic ferromagnetic/antiferromagnetic (FM/AFM) ordering are highly desirable for future spintronic devices. However, the direct growth of their crystals is in its infancy. Here we report a chemical vapor deposition approach to controllably grow layered tetragonal and non-layered hexagonal FeTe nanoplates with their thicknesses down to 3.6 and 2.8 nm, respectively. Moreover, transport measurements reveal these obtained FeTe nanoflakes show a thickness-dependent magnetic transition. Antiferromagnetic tetragonal FeTe with the Néel temperature (TN) gradually decreases from 70 to 45 K as the thickness declines from 32 to 5 nm. And ferromagnetic hexagonal FeTe is accompanied by a drop of the Curie temperature (TC) from 220 K (30 nm) to 170 K (4 nm). Theoretical calculations indicate that the ferromagnetic order in hexagonal FeTe is originated from its concomitant lattice distortion and Stoner instability. This study highlights its potential applications in future spintronic devices.

17.
Small ; 16(30): e2001686, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32521107

RESUMO

Herein, a supermolecular-scale cage-confinement pyrolysis strategy is proposed to build two dielectric electromagnetic wave absorbents, in which MoO2 nanoparticles are sandwiched uniformly between porous carbon shells and reduced graphene oxide (RGO). Both sandwich structures are derived from hybrid hydrogels doped by two different crosslinkers (with/without oxygen bridge), which can precisely confine Mo source (e.g., PMo12 ). Without adding magnetic components, both absorbents exhibit excellent low frequency absorption performance in combination with electrically tunable ability and enhanced reflection loss value, which is superior over other relative 2D dielectric absorbers and satisfies the requirements of portable electronics. Notably, introducing oxygen bridges in the crosslinker generates a more stable confining configuration, which in turn renders its corresponding derivative exhibiting an extra multifrequency electromagnetic wave absorption trait. The intrinsic electromagnetic wave adjustment mechanism of the ternary hybrid absorbent is also explored. The result reveals that the elevated electromagnetic wave absorbing property is attributed to moderate attenuation constant and glorious impendence matching. The cage-confinement pyrolysis route to fabricate 2D MoO2 -based dielectric electromagnetic wave absorbents opens a new path for the design of electromagnetic wave absorbents used in multi/low frequency.

18.
J Chem Phys ; 152(13): 134704, 2020 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-32268743

RESUMO

In this study, we report an oxygen-doped MoS2 quantum dot (O-MoS2 QD) hybrid electrocatalyst for the hydrogen evolution reaction (HER). The O-MoS2 QDs were prepared with a one-pot microwave method by hydrazine-mediated oxygen-doping. The synthetic method is straightforward, time-saving, and can be applied in large scale preparation. Ultra-small O-MoS2 QDs with the average size of 5.83 nm and 1-4 layers can be uniformly distributed on the surface of reduced graphene oxide (RGO). Benefited from the unique structure and the doping effect of oxygen in the MoS2 QDs and the great number of active sites, the O-MoS2 QD hybrid displayed outstanding electrocatalytic performance toward HER. A low overpotential of 76 mV at 10 mA/cm2 and a Tafel slope of 58 mV/dec were obtained in an acidic solution toward HER. Additionally, the resultant O-MoS2 QD hybrid also exhibited excellent stability and durability toward HER, displaying negligible current density loss after 1000 cycles of cyclic voltammetry. The design and synthesis of the electrocatalyst in this work open up a prospective route to prepare active and stable electrocatalysts toward substituting precious metals for hydrogen generation.

19.
ACS Nano ; 14(1): 595-602, 2020 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-31891248

RESUMO

A carbon microtube aerogel (CMA) with hydrophobicity, strong adsorption capacity, and superb recyclability was obtained by a feasible approach with economical raw material, such as kapok fiber. The CMA possesses a great adsorption capacity of 78-348 times its weight. Attributed to its outstanding thermal stability and excellent mechanical properties, the CMA can be used for many cycles of distillation, squeezing, and combustion without degradation, which suggests a potential practical application in oil-water separation. In addition, the adsorption capacity still retained 98% by distillation, 97% by squeezing, and 90% by combustion after 10 cycles. Therefore, the obtained CMA has a broad prospect as an economical, efficient, and environmentally friendly adsorbent.

20.
Adv Mater ; 32(11): e1906972, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31984566

RESUMO

Developing efficient electrocatalysts for alkaline water electrolysis is central to substantial progress of alkaline hydrogen production. Herein, a Ni5 P4 electrocatalyst incorporating single-atom Ru (Ni5 P4 -Ru) is synthesized through the filling of Ru3+ species into the metal vacancies of nickel hydroxides and subsequent phosphorization treatment. Electron paramagnetic resonance spectroscopy, X-ray-based measurements, and electron microscopy observations confirm the strong interaction between the nickel-vacancy defect and Ru cation, resulting in more than 3.83 wt% single-atom Ru incorporation in the obtained Ni5 P4 -Ru. The Ni5 P4 -Ru as an alkaline hydrogen evolution reaction catalyst achieves low onset potential of 17 mV and an overpotential of 54 mV at a current density of 10 mA cm-2 together with a small Tafel slope of 52.0 mV decade-1 and long-term stability. Further spectroscopy analyses combined with density functional theory calculations reveal that the doped Ru sites can cause localized structure polarization, which brings the low energy barrier for water dissociation on Ru site and the optimized hydrogen adsorption free energy on the interstitial site, well rationalizing the experimental reactivity.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA