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1.
BMC Pulm Med ; 24(1): 352, 2024 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-39030536

RESUMO

BACKGROUND: This study aimed to investigate risk factors for acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF) based on baseline high-resolution computed tomography (HRCT). METHODS: This prospective observational study enrolled patients with IPF treated at the General Hospital of Ningxia Medical University between January 2019 and January 2021. HRCT-derived quantitative parameters at baseline were analyzed. RESULTS: A total of 102 patients [92 (90.2%) males with a mean age of 67 years] with IPF were included, with a median follow-up of 32 (24-40.5) months. AE occurred in 30 (29.4%) IPF patients. Multivariable logistic regression analysis identified Doppler transthoracic echocardiography suggestive of pulmonary hypertension (PH) (13.43; 95% CI: 4.18-41.09; P < 0.001), honeycombing (OR 1.08; 95% CI: 1.02-1.14; P = 0.013), and whole lung volume (OR 0.99; 95% CI: 0.99-1.00; P = 0.037) as independent risk factors for AE-IPF. The combination of PH, honeycombing, whole lung volume, and the percentage of predicted forced vital capacity (FVC% pred) showed a high area under the curve from receiver operating characteristic curves of 0.888, with a sensitivity of 90% and specificity of 78%. CONCLUSIONS: This study emphasizes that quantitative CT parameters (honeycombing, whole lung volume) may serve as risk factors for AE-IPF. The combination of honeycombing, whole lung volume, FVC% pred, and PH may aid in predicting AE-IPF.


Assuntos
Fibrose Pulmonar Idiopática , Tomografia Computadorizada por Raios X , Humanos , Masculino , Fibrose Pulmonar Idiopática/diagnóstico por imagem , Fibrose Pulmonar Idiopática/fisiopatologia , Idoso , Estudos Prospectivos , Feminino , Fatores de Risco , Pessoa de Meia-Idade , Progressão da Doença , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Modelos Logísticos , Hipertensão Pulmonar/diagnóstico por imagem , Curva ROC
2.
Chem Biodivers ; 21(6): e202400086, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38619074

RESUMO

The endoperoxide group of artemisinins is universally accepted an essential group for their anti-cancer effects. In this study, a series of D-ring-contracted artemisinin derivatives were constructed by combining ring-contracted artemisinin core with fragments of functional heterocyclic molecules or classical CDK4/6 inhibitors to identify more efficacious breast cancer treatment agents. Twenty-six novel hybridized molecules were synthesized and characterized by HRMS, IR, 1H-NMR and 13C NMR. In antiproliferative activities and kinase inhibitory effects assays, we found that the antiproliferative effects of B01 were close to those of the positive control Palbociclib, with GI50 values of 4.87±0.23 µM and 9.97±1.44 µM towards T47D cells and MDA-MB-436 cells respectively. In addition, the results showed that B01 was the most potent compound against CDK6/cyclin D3 kinase, with an IC50 value of 0.135±0.041 µM, and its activity was approximately 1/3 of the positive control Palbociclib.


Assuntos
Antineoplásicos , Artemisininas , Neoplasias da Mama , Proliferação de Células , Quinase 4 Dependente de Ciclina , Quinase 6 Dependente de Ciclina , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores de Proteínas Quinases , Humanos , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Quinase 6 Dependente de Ciclina/metabolismo , Artemisininas/farmacologia , Artemisininas/química , Artemisininas/síntese química , Quinase 4 Dependente de Ciclina/antagonistas & inibidores , Quinase 4 Dependente de Ciclina/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proliferação de Células/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Neoplasias da Mama/metabolismo , Relação Estrutura-Atividade , Linhagem Celular Tumoral , Estrutura Molecular , Feminino , Relação Dose-Resposta a Droga , Simulação de Acoplamento Molecular
3.
Mikrochim Acta ; 191(4): 224, 2024 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-38556528

RESUMO

A sandwich plasmonic coupled surface enhanced Raman spectroscopy (SERS) tape is proposed prepared by peeling the chemical printed silver nanocorals (AgNCs) from Cu sheet with adhesive tape, which can sample targets from food surface and sandwich them between substrates and Cu sheet for SERS detection. The solid-to-solid transformation method for fabricating SERS tapes can effectively avoid the weakening of tape stickiness during the preparation process. The sandwich plasmonic coupled structure of AgNC substrate, targets, and Cu sheet display excellent SERS activity (EF = 1.62 × 107) for sensitive determination of analytes. In addition, due to the high heat conductivity of Cu sheet, the thermal effect of laser irradiation during SERS detection cannot damage the AgNC tapes, which ensures the reproducibility of subsequent quantification. The sandwich plasmonic coupled SERS tape is demonstrated to quantify malachite green (MG) and methyl parathion (MP) with good linear coefficients (> 0.98) by two typical calibration plots under different concentration ranges. The limit of detection (LOD) of the method is 0.17 ng/cm2 and 0.48 µg/cm2 (S/N = 3) for MG and MP. This method can realize the quantitative determination of MP and MG on the surface of fruits and fish scale with recoveries of 93-113%. The satisfactory detection results demonstrate the proposed sandwich plasmonic coupled AgNC tape can be successfully applied to SERS-based point-of-care testing (POCT) for pesticide residue determination, which will provide a new path for designing and constructing SERS tapes.


Assuntos
Resíduos de Praguicidas , Animais , Resíduos de Praguicidas/análise , Reprodutibilidade dos Testes , Análise Espectral Raman/métodos , Frutas/química
4.
Angew Chem Int Ed Engl ; : e202412139, 2024 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-39039693

RESUMO

Ru-based pyrochlores (e.g., Y2Ru2O7-d) are promised to replace IrO2 in polymer electrolyte membrane (PEM) electrolyzers. It is significant to reveal the cliff attenuation on the oxygen evolution reaction (OER) performance of these pyrochlores. In this work, we monitor the structure changes and electrochemical behavior of Y2Ru2O7-d over the OER process, and it is found that the reason of decisive OER inactivation is derived from an insulator transition occurred within Y2Ru2O7-d due to its inner ²perfecting² lattice induced by continuous atom rearrangement. Therefore, a stabilization strategy of the Ir-substituted Y2Ru2O7-d is proposed to alleviate this undesirable behavior. The double-exchange interaction between Ru and Ir in [RuO6] and [IrO6] octahedra leads the charge redistribution with simultaneous spin configuration adjustment. The electronic state in newly formed octahedrons centered with Ru 4d3 (with the state of eg'2--a1g-1 eg0) and Ir 5d6 (eg'4a1g-2 eg0) relieves the uneven electron distributions in [RuO6] orbital. The attenuated Jahn-Teller effect alleviates atom rearrangement, represented as the mitigation of insulator transition, surface reconstruction, and metal dissolution. As results, the Ir-substituted Y2Ru2O7-d presents the greatly improved OER stability and PEM durability. This study unveils the OER degradation mechanism and stabilization strategy for material design of Ru-based OER catalysts for electrochemical applications.

5.
Small ; 19(10): e2206698, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36642791

RESUMO

Pyrochlore ruthenate (Y2 Ru2 O7-δ ) is highlighted as a promising oxygen evolution reaction (OER) catalyst for water splitting in polymer electrolyte membrane electrolyzers. However, an efficient electronic modulation strategy for Y2 Ru2 O7-δ is required to overcome its electrochemical inertness. Herein, a surface manipulation strategy involving implanting MoOx moieties on nano Y2 Ru2 O7-δ (Mo-YRO) using wet chemical peroxone method is demonstrated. In contrast to electronic structure regulation by intramolecular charge transfer (i.e., substitutional strategies), the heterogeneous Mo-O-Ru micro-interfaces facilitate efficient intermolecular electron transfer from [RuO6 ] to MoOx . This eliminates the bandgap by inducing Ru 4d delocalization and band alignment rearrangement. The MoOx modifiers also alleviate distortion of [RuO6 ] by shortening Ru-O bond and enlarging Ru-O-Ru bond angle. This electronic and geometric structure tailoring enhances the OER performance, showing a small overpotential of 240 mV at 10 mA cm-2 . Moreover, the electron-accepting MoOx moieties provide more electronegative surfaces, which serve as a protective "fence" to inhibit the dissolution of metal ions, thereby stabilizing the electrochemical activity. This study offers fresh insights into the design of new-based pyrochlore electrocatalysts, and also highlights the versatility of surface engineering as a way of optimizing electronic structure and catalytic performance of other related materials.

6.
Opt Express ; 31(11): 17569-17579, 2023 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-37381487

RESUMO

Holography is an advanced imaging technology where image information can be reconstructed without a lens. Recently, multiplexing techniques have been widely adapted to realize multiple holographic images or functionalities in a meta-hologram. In this work, a reflective four-channel meta-hologram is proposed to further increase the channel capacity by simultaneously implementing frequency and polarization multiplexing. Compared to the single multiplexing technique, the number of channels achieves a multiplicative growth of the two multiplexing techniques, as well as allowing meta-devices to possess cryptographic characteristics. Specifically, spin-selective functionalities for circular polarizations can be achieved at lower frequency, while different functionalities can be obtained at higher frequency under different linearly polarized incidences. As an illustrative example, a four-channel joint-polarization-frequency-multiplexing meta-hologram is designed, fabricated, and characterized. The measured results agree well with the numerically calculated and full-wave simulated ones, which provides the proposed method with great potential in numerous opportunities such as multi-channel imaging and information encryption technology.

7.
BMC Infect Dis ; 23(1): 35, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36670360

RESUMO

BACKGROUND: Escherichia fergusonii is a rare opportunistic pathogen in humans and animals, especially with biofilm. METHODS: In one case, E. fergusonii with biofilm was detected in the bile, and silver staining was used to prove it had biofilm. The clinical characteristics and drug susceptibility of eight cases of E. fergusonii retrieved from the literature were also summarized. RESULTS: This is a case of E. fergusonii with biofilm, which has not been reported in China. The 8 cases retrieved from the literature did not specify whether they had biofilm, but we analyzed their clinical characteristics and drug susceptibility. All patients were treated with antimicrobial drugs. 8 cases showed sensitivity to piperacillin/tazobactam and imipenem in 6 cases (75%), but poor sensitivity to levofloxacin and ciprofloxacin. CONCLUSION: The silver staining method proved biofilm in this case, which is the first case of E. fergusonii with biofilm in China.


Assuntos
Antibacterianos , Anti-Infecciosos , Animais , Humanos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Escherichia , Biofilmes , Testes de Sensibilidade Microbiana
8.
Opt Express ; 30(16): 28954-28965, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-36299081

RESUMO

A visible light depth modulation based on a metasurface consisting of TiO2 nanorings and SiO2 substrate is proposed to significantly enhance the saturation and structural colors' gamut. Compared with the nanostructure of the TiO2 nanodisks, the developed TiO2 nanorings can enhance monochromatic excitation by inhibiting the multipole mode, particularly electric quadrupole (EQ) mode at a shorter wavelength. Furthermore, when TiO2 nanorings are combined with a refractive index matching layer - water, reflection bandwidth, and background reflection are reduced, and the brightness and color purity are significantly enhanced. The novel and unique nanostructures developed can generate a significant gamut of 140% sRGB and 103% Adobe RGB. Additionally, the color structure based on the TiO2 nanoring metasurface is sensitive to the surrounding medium's refractive index and can be employed in sensor display and other fields, as well as to amplify color information in high resolution display and imaging applications.

9.
BMC Pulm Med ; 22(1): 438, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36424599

RESUMO

BACKGROUND: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have considerably high mortality and re-hospitalisation rate. Diaphragmatic dysfunction (DD) is common in COPD patients. However, whether diaphragmatic dysfunction is related to acute exacerbation is yet to be elucidated. This study aimed to evaluate the diaphragm function by magnetic resonance imaging (MRI) in COPD patients and assess whether the impact of DD may help predict AECOPD. METHODS: 20 healthy adult volunteers and 80 COPD patients were enrolled. The diaphragms function parameters were accessed by MRI. Patients were guided to start self-management by the Telehealth-based monitoring system following the enrolment. Events of acute exacerbation of COPD were recorded by the system and confirmed by healthcare providers. Binary univariate and multivariate logistic regression analyses were performed to investigate the factors associated with the frequency of AECOPD. Receiver operating characteristic (ROC) curves were further used to assess the value of prediction indexes. RESULTS: Fifty-nine COPD patients completed a one-year follow-up based on the Telehealth-based monitoring system. The clinical outcomes showed that the diaphragm function parameters at the end of maximal breathing were lower in the COPD group than in the healthy control group (P < 0.05). ANOVA showed significant differences among Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages for diaphragm function parameters, including chest wall motion, lung area, upper-lower diameter, and the diaphragm thickening fraction at the end of maximal breathing (P < 0.05). Moreover, significant differences in diaphragm function parameters were observed between patients with infrequent AECOPD (n = 28) and frequent AECOPD (n = 31) based on the frequency of AECOPD (P < 0.05). The diaphragm thickening fraction and the chest wall motion were associated with AECOPD after adjusting for age, sex, BMI, and lung functions, and the combination of predictions showed better accuracy in predicting the frequency of AECOPD. CONCLUSIONS: In COPD patients, diaphragm function parameters correlate with the severity of airflow limitation. The diaphragm thickening fraction and the chest wall motion were associated with the frequency of AECOPD and can predict it.


Assuntos
Doença Pulmonar Obstrutiva Crônica , Telemedicina , Adulto , Humanos , Diafragma/diagnóstico por imagem , Estudos Prospectivos , Imageamento por Ressonância Magnética
10.
Chem Soc Rev ; 50(23): 12985-13011, 2021 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-34751683

RESUMO

Applications of phthalocyanines (Pcs) in electrocatalysis-including the oxygen reduction reaction (ORR), the carbon dioxide reduction reaction (CO2RR), the oxygen evolution reaction (OER), and the hydrogen evolution reaction (HER)-have attracted considerable attention recently. Pcs and their derivatives are more attractive than many other macrocycles as electrocatalysts since, although they are structurally related to natural porphyrin complexes, they offer the advantages of low cost, facile synthesis and good chemical stability. Moreover, their high tailorability and structural diversity mean Pcs have great potential for application in electrochemical devices. Here we review the structure and composition of Pcs, methods of synthesis of Pcs and their analogues, as well as applications of Pc-based heterogeneous electrocatalysts. Optimization strategies for Pc-based materials for electrocatalysis of ORR, CO2RR, OER and HER are proposed, based on the mechanisms of the different electrochemical reactions. We also discuss the structure/composition-catalytic activity relationships for different Pc materials and Pc-based electrocatalysts in order to identify future practical applications. Finally, future opportunities and challenges in the use of molecular Pcs and Pc derivatives as electrocatalysts are discussed.


Assuntos
Hidrogênio , Oxigênio , Catálise , Indóis
11.
Opt Express ; 29(20): 32491-32504, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34615318

RESUMO

Dynamic color modulation in the composite structure of a graphene microelectromechanical system (MEMS)-photonic crystal microcavity is investigated in this work. The designed photonic crystal microcavity has three resonant standing wave modes corresponding to the three primary colors of red (R), green (G) and blue (B), forming strong localization of light in three modes at different positions of the microcavity. Once graphene is added, it can govern the transmittance of three modes. When graphene is located in the antinode of the standing wave, it has strong light absorption and therefore the structure's transmittance is lower, and when graphene is located in the node of the standing wave, it has weak light absorption and therefore the structure's transmittance is higher. Therefore, the graphene absorption of different colors of light can be regulated dynamically by applying voltages to tune the equilibrium position of the graphene MEMS in the microcavity, consequently realizing the output of vivid monochromatic light or multiple mixed colors of light within a single pixel, thus greatly improving the resolution. Our work provides a route to dynamic color modulation with graphene and provides guidance for the design and manufacture of high resolution, fast modulation and wide color gamut interferometric modulator displays.

12.
Chemistry ; 27(42): 10987-10997, 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34008878

RESUMO

Exploring high-performance non-precious-metal electrocatalysts for the oxygen reduction reaction (ORR) is critical. Herein, a scalable and cost-effective strategy is reported for the construction of one-dimensional carbon nanofiber architectures with simultaneous decoration of single Fe-Nx sites and highly dispersed Fe/Fe3 C nanoparticles for efficient ORR, through the FeIII -complex-assisted electrospinning of gelatin nanofibers with subsequent pre-oxidation and carbonization. Results show that the presence of a FeIII complex enables the 1D gelatin nanofibers to be well retained during the pre-oxidation process. Owing to the distinct 1D nanofiber structure and the synergistic effect of Fe/Fe3 C and Fe-Nx sites, the resulting electrocatalyst is highly active for ORR with a half-wave potential of 0.885 V (outperforming commercial Pt/C) and a superior electrochemical stability in alkaline electrolytes. Similarly, it also shows a high power density (144.7 mW cm-2 ) and a superior stability in Zn-air batteries. This work opens a path for the design and synthesis of 1D carbon electrocatalyst for efficient ORR catalysis.

13.
Eur Spine J ; 30(2): 524-533, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32876731

RESUMO

OBJECTIVE: To propose a novel classification and scoring system called the posterior ligament-bone injury classification and severity score (PLICS) that offers a quantitative score to guide the need for posterior stabilization in addition to anterior reconstruction for subaxial cervical fracture dislocations (SCFDs). METHODS: A total of 456 patients with SCFDs were prospectively included. Patients with PLICS ≥ 7 together with extremely unstable lateral mass fracture (EULMF) were classified as high-risk group, and the other patients were classified as low-risk group. For patients in the low-risk group, anterior-only reconstruction was performed; for patients in the high-risk group, additional posterior lateral mass fixation and fusion was performed after anterior reconstruction. Clinical outcome evaluation included using the visual analogue score (VAS), the Neck Disability Index (NDI), and the American Spinal Injury Association (ASIA) impairment scale. The change in the local sagittal alignment kyphosis Cobb angle was also recorded. RESULTS: A total of 370 patients (81.1%) completed the minimal 12-month follow-ups, including 321 patients of low-risk group and 49 patients of high-risk group. Compared with the average VAS score preoperatively, the score at 12-month follow-up was significantly improved (from 6.1 + 0.3 to 1.1 + 0.2 in the low-risk group, P < 0.001; from 6.4 + 0.2 to 1.4 + 0.2 in the high-risk group, P < 0.001). The average NDI score at the 12-month follow-up was statistically low in the low-risk group (8.8 + 2.5 vs 13.8 + 3.4, P = 0.034). At least more than one grade improvement in the ASIA scale was observed in 80.5% of all patients. The local kyphosis Cobb angle at the injured segment averaged improved in both groups. CONCLUSION: A PLICS score ≥ 7 together with EULMF can be the threshold for posterior stabilization in addition to anterior reconstruction for the patients with SCFDs.


Assuntos
Fratura-Luxação , Fraturas da Coluna Vertebral , Fusão Vertebral , Algoritmos , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/lesões , Vértebras Cervicais/cirurgia , Fixação Interna de Fraturas , Humanos , Ligamentos , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento
14.
Angew Chem Int Ed Engl ; 60(40): 21899-21904, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34331724

RESUMO

The development of active and stable platinum (Pt)-based oxygen reduction reaction (ORR) electrocatalysts with good resistance to poisoning is a prerequisite for widespread practical application of fuel cells. An effective strategy for enhancing the electrocatalytic performance is to tune or control the physicochemical state of the Pt surface. Herein, we show a general surface-engineering approach to prepare a range of nanostructured Pt alloys by coating with alloy PtBi shells. FePt@PtBi core-shell nanoparticles showed the best ORR performance with a mass activity of 0.96 A mgPt -1 and a specific activity of 2.06 mA cm-2 , respectively 7 times and 11 times those of the corresponding values for benchmark Pt/C. Moreover, FePt@PtBi shows much better tolerance to methanol and carbon monoxide than conventional Pt-based electrocatalysts. The observed comprehensive enhancement in ORR performance of FePt@PtBi can be attributed to the increased compressive strain of the Pt surface due to in-plane shearing resulting from the presence of the large Bi atoms in the surface-structured PtBi overlayers, as well as charge displacement via Pt-Bi bonding which mitigates crossover issues.

15.
J Am Chem Soc ; 142(41): 17524-17530, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-32942851

RESUMO

Two-dimensional (2D) conjugated aromatic networks (CAN) have been fabricated by ball milling of polymeric cobalt phthalocyanine precursors edge-functionalized with different aromatic acid anhydride substituents. The optimal CAN, obtained by using tetraphenylphthalic anhydride, consists of uniform and thin (2.9 nm) layers with a high BET surface (92 m2 g-1), resulting in well-defined Co-N4 active sites with a high degree of exposure. Thence, this material exhibits excellent electrocatalytic oxygen reduction reaction (44 mA mgcat.-1). Compared to a benchmark Pt/C catalyst, this value denotes 1.2- and 6.0-fold enhancements, respectively, in terms of the mass of Pt and total Pt/C. When utilized as air electrode catalysts in Zn-air batteries, this material provides a maximum areal power density (137 mW cm-2) and mass power density (0.68 W mgcat.-1), values which also clearly surpass those of benchmark Pt/C catalyst. This support-free and pyrolysis-free strategy developed in this work delivers a novel route for the applications of 2D materials in clean energy conversion and storage.

16.
Small ; 16(51): e2005048, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33314718

RESUMO

Strengthening the interfacial interaction in heterogeneous catalysts can lead to a dramatic improvement in their performance and allow the use of smaller amounts of active noble metal, thus decreasing the cost without compromising their activity. In this work, a facile phase-segregation method is demonstrated for synthesizing platinum-tin oxide hybrids supported on carbon black (PtSnO2 /C) in situ by air annealing PtSn alloy nanoparticles on carbon black. Compared with a control sample formed by preloading SnO2 on carbon support followed by deposition of Pt nanoparticles, the phase-segregation-derived PtSnO2 /C exhibits a more strongly coupled PtSnO2 interface with lattice overlap of Pt (111) and SnO2 (200), along with enhanced electron transfer from SnO2 to Pt. Furthermore, the PtSnO2 active sites show a strong ability to degrade reactive oxygen species. As a result, the PtSnO2 /C nanohybrids exhibit both excellent activity and stability as a catalyst for the oxygen reduction reaction, with an overall performance which is superior to both the control sample and commercial Pt/C catalyst. This phase-segregation method can be expected to be applicable in the preparation of other strongly coupled nanohybrids and offers a new route to high-performance heterogeneous catalysts for low-cost energy conversion devices.

17.
Appl Opt ; 59(28): 9003-9009, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33104589

RESUMO

Black phosphorus (BP) is an important two-dimensional material that plays a key role in new photoelectric devices. In this work, a triple-band BP-based absorber was proposed, in which a monolayer BP is coupled with the missing angle rectangular structure. Due to the critical coupling of the guided resonance, the BP absorber achieves a triple-band absorption. The results showed that the absorption spectra at 2901.76 nm, 3810.71 nm, and 4676.97 nm under TM polarization achieve a high absorption of 95.45%, 98.68%, and 98.06%, respectively. In addition, the absorption peak and resonance wavelength can be flexibly adjusted by the electron doping of BP, the geometrical parameters of the structure, and the refractive index of the dielectric substrate. Because of the anisotropy properties of BP, the structure exhibits polarization-dependent absorption characteristics. Thus, the missing angle rectangular structure will provide a potential to design mid-infrared absorbers and shows a significant practical application in many photoelectric devices such as photodetectors, modulators, and optical switches.

18.
Angew Chem Int Ed Engl ; 59(46): 20423-20427, 2020 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-32692446

RESUMO

High-performance electrocatalysts for the hydrogen evolution reaction (HER) have an important role to play in the development of renewable energy. Platinum remains the most efficient known HER electrocatalyst. Therefore, it is necessary to find ways to maximize Pt utilization in actual practical applications. Herein we demonstrate a facile strategy for synthesizing RuCeOx -supported, selectively loaded, atomic Pt (0.49 wt. %) (denoted Pt/RuCeOx -PA) by photoactivation at ambient temperature and pressure. Through the photoelectron transfer at the Mott-Schottky heterojunction in RuCeOx , Pt atoms became embedded into the RuO2 lattice. The resulting selectively loaded Pt-O-Ru moieties in Pt/RuCeOx -PA give a stronger hydrogen spillover effect than Pt complexes randomly loaded by either chemical activation or thermal activation. As a result, Pt/RuCeOx -PA shows superior HER performance to the materials prepared by random loading and is even better than a commercial Pt/C catalyst with much higher Pt loading (20 wt. %) at high current densities (from 50-600 mA cm-2 ).

19.
Chemistry ; 25(22): 5768-5776, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30740789

RESUMO

An ice/salt-assisted strategy has been developed to achieve the green and efficient synthesis of ultrathin two-dimensional (2D) micro/mesoporous carbon nanosheets (CNS) with the dominant active moieties of Fe-N4 (Fe-N-CNS) as high-performance electrocatalysts for the oxygen reduction reaction (ORR). The strategy involves freeze-drying a mixture of iron porphyrin and KCl salt using ice as template followed by a confined pyrolysis with KCl as an independent sealed nanoreactor to facilitate the formation of 2D carbon nanosheets, N incorporation, and porosity creation. The well-defined assembly of ultrathin 2D carbon nanosheets ensures high utilization of D1 and D3 Fe-N4 active sites, and effectively promotes the mass transport of ORR reactants by virtue of the pronounced mesoporous structure. The resulting Fe-N-CNS electrocatalyst was shown to exhibit superior ORR activity, better electrochemical durability, and methanol tolerance towards ORR in alkaline electrolyte relative to the commercial Pt/C electrocatalyst.

20.
Chemistry ; 25(22): 5652-5657, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30768737

RESUMO

Breaking the electroneutrality of sp2 carbon lattice is a viable way for nanocarbon material to modulate the charge delocalization and to further alter the electrocatalytic activity. Positive charge spreadsheeting is preferable for catalyzing the oxygen reduction reaction (ORR) and other electrochemical reactions. Analogously to the case of intramolecular charge transfer by heteroatom doping, electrons in the conjugated carbon lattice can be redistributed by the intermolecular charge transfer from the nanocarbon material to the polyelectrolyte. A copolymeric electrolyte, epichlorohydrin-dimethylamine copolymer (EDC) was synthesized. The EDC-modified carbon nanotube (CNT) hybrid was subsequently fabricated by sonication treatment and served as a metal-free carbonaceous electrocatalyst with remarkable catalytic activity and stability. The resultant hybrid presents positive charge spreadsheeting on CNT as a result of the interfacial electron transfer from CNT to EDC. DFT calculations were further carried out to reveal that the enhancement of the wrapped EDC polyelectrolyte originates from the synergetic effect of the quaternary ammonium-hydroxyl covalently bonded structure. The CNT-EDC hybrid not only provides an atomically precise regulation to modulate nanocarbon materials from inactive carbonaceous materials into efficient metal-free catalysts, but it also opens new avenues to develop metal-free catalysts with well-defined and highly active sites.

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