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1.
Nucleic Acids Res ; 52(D1): D1380-D1392, 2024 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-37889076

RESUMEN

DNA methylation plays a crucial role in tumorigenesis and tumor progression, sparking substantial interest in the clinical applications of cancer DNA methylation biomarkers. Cancer-related whole-genome bisulfite sequencing (WGBS) data offers a promising approach to precisely identify these biomarkers with differentially methylated regions (DMRs). However, currently there is no dedicated resource for cancer DNA methylation biomarkers with WGBS data. Here, we developed a comprehensive cancer DNA methylation biomarker database (MethMarkerDB, https://methmarkerdb.hzau.edu.cn/), which integrated 658 WGBS datasets, incorporating 724 curated DNA methylation biomarker genes from 1425 PubMed published articles. Based on WGBS data, we documented 5.4 million DMRs from 13 common types of cancer as candidate DNA methylation biomarkers. We provided search and annotation functions for these DMRs with different resources, such as enhancers and SNPs, and developed diagnostic and prognostic models for further biomarker evaluation. With the database, we not only identified known DNA methylation biomarkers, but also identified 781 hypermethylated and 5245 hypomethylated pan-cancer DMRs, corresponding to 693 and 2172 genes, respectively. These novel potential pan-cancer DNA methylation biomarkers hold significant clinical translational value. We hope that MethMarkerDB will help identify novel cancer DNA methylation biomarkers and propel the clinical application of these biomarkers.


Asunto(s)
Biomarcadores de Tumor , Carcinogénesis , Metilación de ADN , Bases de Datos Genéticas , Humanos , Biomarcadores de Tumor/genética , Metilación de ADN/genética , Secuenciación Completa del Genoma , Carcinogénesis/genética , Elementos de Facilitación Genéticos
2.
Proc Natl Acad Sci U S A ; 120(8): e2218405120, 2023 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-36787368

RESUMEN

Most metals adopt simple structures such as body-centered cubic (BCC), face-centered cubic (FCC), and hexagonal close-packed (HCP) structures in specific groupings across the periodic table, and many undergo transitions to surprisingly complex structures on compression, not expected from conventional free-electron-based theories of metals. First-principles calculations have been able to reproduce many observed structures and transitions, but a unified, predictive theory that underlies this behavior is not yet in hand. Discovered by analyzing the electronic properties of metals in various lattices over a broad range of sizes and geometries, a remarkably simple theory shows that the stability of metal structures is governed by electrons occupying local interstitial orbitals and their strong chemical interactions. The theory provides a basis for understanding and predicting structures in solid compounds and alloys over a broad range of conditions.

3.
Chemphyschem ; 25(20): e202400232, 2024 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-39031895

RESUMEN

Near-infrared (NIR) light has characteristics of invisibility to human eyes, less background interference, low light scattering, and strong cell penetration. Therefore, NIR luminescent materials have significant applications in imaging, sensing, energy, information storage and display. The development of NIR luminescent materials thus has emerged as a highly dynamic area of research in the realm of contemporary materials. To date, NIR luminescent materials are roughly divided into inorganic materials and organic materials. Compared with inorganic materials, organic NIR luminescent materials have become a hot research topic in recent years due to their rich sources, easy control of structure, simple preparation process, low cost, and good film-forming properties. Among them, iridium(III) [Ir(III)] complexes exhibit excellent properties such as thermal stability, simple synthesis, easy color modulation, short excited state lifetimes, and high brightness, thus becoming one of the ideal luminescent material systems for preparing high-quality organic light-emitting diodes. Therefore, how to obtain Ir(III) complexes with NIR emission and high efficiency through molecular design is a necessary and promising research topic. This work reviews the research progress of representative NIR Ir(III) complexes bearing isoquinoline-, phenazine-, and phthalazine-based ligands reported in recent years and introduces the design strategies and electroluminescent performances of NIR Ir(III) complexes.

4.
Health Qual Life Outcomes ; 21(1): 56, 2023 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-37280621

RESUMEN

BACKGROUND: It is significant for the healthy outcome of patients with psoriasis (PSO) to improve their self-management efficacy. A standardized assessment tool, however, was lacking. Therefore, we aimed to develop a self-management efficacy questionnaire for patients with PSO (SMEQ-PSO) and evaluate its psychometric properties. METHODS: A cross-sectional study developing clinical evaluation tool was conducted from October 2021 to August 2022. In the process of developing SMEQ-PSO, three phases were involved: item generation, item evaluation, and psychometric evaluation. RESULTS: The SMEQ-PSO with five dimensions and 28 items was developed. The questionnaire's content validity index was 0.976. Exploratory factor analysis indicated a five-factor structure (self-efficacy of psychosocial adaptation, self-efficacy of daily life management, self-efficacy of skin management, self-efficacy of disease knowledge management and self-efficacy of disease treatment management) that explained 62.039% of the total variance. Confirmatory factor analysis indicated appropriate fit of the five-factor model. The overall Cronbach'α coefficient was 0.930, the test-retest reliability was 0.768 and the split half reliability coefficients was 0.952. CONCLUSIONS: The 28-item SMEQ-PSO is a reliable and valid tool that can be used to assess the self-management efficacy among patients with PSO and provide personalized interventions based on their individual circumstances to improve their health outcomes.


Asunto(s)
Psoriasis , Automanejo , Humanos , Autoeficacia , Psicometría/métodos , Reproducibilidad de los Resultados , Estudios Transversales , Calidad de Vida , Psoriasis/terapia , Psoriasis/psicología , Encuestas y Cuestionarios
5.
BMC Nurs ; 22(1): 259, 2023 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-37550733

RESUMEN

BACKGROUND: The benefits of home-based cardiac rehabilitation exercise are well-established and depend on long-term adherence. However, there is no uniform and recognized cardiac rehabilitation criterion to assess home-based cardiac rehabilitation exercise adherence for patients with cardiovascular disease. This study aimed to develop a home-based cardiac rehabilitation exercise adherence scale and to validate its psychometric properties among patients with chronic heart failure. METHODS: The dimensions and items of the scale were created based on grounded theory research, literature content analysis, and defined by a Delphi survey. Item analysis was completed to assess the discrimination and homogeneity of the scale. Factor analysis was adopted to explore and validate the underlying factor structure of the scale. Content validity and calibration validity were evaluated using the Delphi survey and correlation analysis, respectively. Reliability was evaluated by Cronbach's α coefficients, split-half reliability coefficients, and test-retest reliability coefficients. RESULTS: A scale covering four dimensions and 20 items was developed for evaluating home-based cardiac rehabilitation exercise adherence. The content validity index of the scale was 0.986. In exploratory factor analysis, a four-factor structure model was confirmed, explaining 75.1% of the total variation. In confirmatory factor analysis, the four-factor structure was supported by the appropriate fitting indexes. Calibration validity of the scale was 0.726. In terms of reliability, the Cronbach's α coefficient of the scale was 0.894, and the Cronbach's α coefficients of dimensions ranged from 0.848 to 0.914. The split-half reliability coefficient of the scale was 0.695. The test-retest reliability coefficient of the scale was 0.745. CONCLUSION: In this study, a home-based cardiac rehabilitation exercise adherence scale was developed and its appropriate psychometric properties were confirmed.

6.
Angew Chem Int Ed Engl ; 62(41): e202309739, 2023 Oct 09.
Artículo en Inglés | MEDLINE | ID: mdl-37626014

RESUMEN

Highly efficient near-infrared (NIR) emitters have significant applications in medical and optoelectronic fields, but the development stays a great challenge due to the energy gap law. Here, we report two NIR phosphorescent Ir(III) complexes which display emission peaks around 730 nm with a narrow full width at half maximum of only 43 nm. Therefore, pure NIR luminescence can be obtained without having a very long emission wavelength, thus alleviating the restriction of the energy gap law, and obtaining impressively high photoluminescence quantum yield up to 0.70. More importantly, the pure NIR organic light-emitting diode (OLED) fabricated by the solution-processed mothed shows outstanding device performance with the highest external quantum efficiency of 16.43 %, which sets a new record for solution-processed NIR-OLEDs based on different emitters. This work sheds light on the development of Ir(III) complexes with narrowband emissions as highly efficient pure NIR-emitters.

7.
Phys Chem Chem Phys ; 24(27): 16884-16890, 2022 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-35789236

RESUMEN

Clathrates are inclusion compounds featured with host framework cages and trapped guest atoms or small molecules. Recently, the first boron-carbon (B-C) clathrate SrB3C3 was successfully synthesized at high pressures near 50 GPa. Upon the substitution of guest atoms, clathrates exhibit tunable applications. For example, LaB3C3 possesses an indirect band gap of near 1.3 eV, whereas the ScB3C3 clathrate is ferroelectric with an above-room-temperature Curie temperature of ∼370 K. To the best of our knowledge, however, there is no report on the investigation of B-C framework clathrates with non-equivalent B : C ratios. By using first-principles swarm-intelligence structure searching computations, we identified two metastable I4/mmm SrB2C4 and LaB4C2 clathrates at 50 GPa, and the framework cage contains six quadrilaterals and eight hexagons with a trapped guest metal located at the center. Their dynamic and enthalpy stabilities may be retained at ambient pressure. Moreover, the possible clathrates are extended by the substitution of the guest atoms with other metals in groups 2, 3, and 4, showing a tunable superconducting critical temperature (Tc) and considerable Vickers hardness (Hv). Intriguingly, a metal-to-semiconductor transition occurs in MB2C4 as the atomic number order of alkaline earth metals increases (M: Mg → Ca → Sr → Ba). The estimated Tc value for I4/mmm SrB4C2 is 19.2 K, while SrB2C4 and BaB2C4 are evaluated as superhard materials with Hv values of 43.6 and 41.2 GPa under ambient conditions, respectively.

8.
Support Care Cancer ; 30(12): 10043-10050, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36350381

RESUMEN

BACKGROUND: Serum lipid management is an important health management goal for breast cancer patients with endocrine therapy, and serum lipid knowledge is a substantial factor influencing patients' serum lipid management behavior. The aim of this study was to explore the relationship between family support, serum lipid knowledge and quality of life in breast cancer women with endocrine therapy. METHODS: Through convenience sampling, 301 women who had been treated in the First Affiliated Hospital of China Medical University and Liaoning Cancer Hospital were selected to fill in the questionnaire of knowledge-attitude-practice (KAP) on serum lipids, family support questionnaire (FSQ), and the functional assessment of cancer therapy-breast cancer (FACT-B). Pearson correlation coefficient was used to analyze the correlation between the three. Multiple linear regression model was used to analyze the influencing factors of quality of life in breast cancer patients with endocrine therapy. RESULTS: The average score of KAP on serum lipids was 42.62 ± 7.333, the average score of family support was 12.55 ± 2.390, and the average score of quality of life was 97.13 ± 21.347, all above the medium level. Family support of breast cancer women with endocrine therapy was positively correlated with serum lipid knowledge and quality of life. Disease stage, family support, and serum lipid knowledge were the influencing factors of quality of life of breast cancer women with endocrine therapy. CONCLUSION: Good family support is associated with better serum lipid knowledge in breast cancer women with endocrine therapy. Therefore, interventions that aim to improve the level of family support may be one way to improve the knowledge level of serum lipid, prevent cardiovascular and cerebrovascular diseases, and improve the quality of life.


Asunto(s)
Neoplasias de la Mama , Calidad de Vida , Humanos , Femenino , Encuestas y Cuestionarios , Quimioterapia Adyuvante/efectos adversos , Lípidos/uso terapéutico
9.
Adv Funct Mater ; 30(31): 2001920, 2020 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-32774197

RESUMEN

The 2D semiconductor indium selenide (InSe) has attracted significant interest due its unique electronic band structure, high electron mobility, and wide tunability of its band gap energy achieved by varying the layer thickness. All these features make 2D InSe a potential candidate for advanced electronic and optoelectronic applications. Here, the discovery of new polymorphs of InSe with enhanced electronic properties is reported. Using a global structure search that combines artificial swarm intelligence with first-principles energetic calculations, polymorphs that consist of a centrosymmetric monolayer belonging to the point group D 3d are identified, distinct from well-known polymorphs based on the D 3h monolayers that lack inversion symmetry. The new polymorphs are thermodynamically and kinetically stable, and exhibit a wider optical spectral response and larger electron mobilities compared to the known polymorphs. Opportunities to synthesize these newly discovered polymorphs and viable routes to identify them by X-ray diffraction, Raman spectroscopy, and second harmonic generation experiments are discussed.

10.
Phys Chem Chem Phys ; 22(4): 2122-2129, 2020 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-31907508

RESUMEN

The two-dimensional (2D) atomically thin layered materials have attracted significant attention for constructing next-generation integrated electronic and optoelectronic devices. A special class of 2D materials composed of quasi one-dimensional (1D) atomic chains that show intriguing properties are less studied. Here, two Se-containing 2D layered materials α-Se and Sb2Se3 that have quasi-1D atomic chains are investigated via first-principles electronic structure calculations. Results shows that the electronic properties of n-monolayers (n-MLs) stacked α-Se and Sb2Se3 exhibit distinct layer-dependence electronic properties. The band gap of 2D α-Se remarkably decreases with increasing thickness, whereas the band gap of 2D Sb2Se3 show negligible change with thickness. The evolution of lattice phonon frequencies with thickness also show similar distinction. The underpinnings of the diverse electronic properties are attributed to the different electronic coupling among the layers of α-Se and Sb2Se3 that results in different van der Waals interactions among chains/layers. Our study demonstrates the rich diversity in the properties of 2D layered materials composed of lower-dimensional structural motifs.

11.
J Am Chem Soc ; 141(4): 1599-1605, 2019 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-30608679

RESUMEN

Graphene and phosphorene are two major types of atomically thin two-dimensional materials under extensive investigation. However, the zero band gap of graphene and the instability of phosphorene greatly restrict their applications. Here, we make first-principle unbiased structure search calculations to identify a new buckled graphene-like PC6 monolayer with a number of desirable functional properties. The PC6 monolayer is a direct-gap semiconductor with a band gap of 0.84 eV, and it has an extremely high intrinsic conductivity with anisotropic character (i.e., its electron mobility is 2.94 × 105 cm2 V-1 s-1 along the armchair direction, whereas the hole mobility reaches 1.64 × 105 cm2 V-1 s-1 along the zigzag direction), which is comparable to that of graphene. On the other hand, PC6 shows a high absorption coefficient (105 cm-1) in a broad band, from 300 to 2000 nm. Additionally, its direct band gap character can remain within a biaxial strain of 5%. All these appealing properties make the predicted PC6 monolayer a promising candidate for applications in electronic and photovoltaic devices.

12.
Chem Rec ; 19(8): 1710-1728, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30637911

RESUMEN

Color-tuning for phosphorescent emitters in organic light-emitting diodes (OLEDs) across the entire visible spectrum is prerequisite to fulfil flexible full-color displays and white solid-state lighting. Heteroleptic 2-phenylpyridine-type (ppy-type) Ir(III) and Pt(II) complexes as phosphorescent emitters have been well exploited in the electroluminescence (EL) field due to their outstanding EL performance. Furthermore, the photophysical characters of these heteroleptic Ir(III) and Pt(II) complexes are generally dominated by the nature of cyclometalating ppy-type ligands. Accordingly, either sophisticated modification or judicious combination of different cyclometalating ppy-type ligands will provide a wonderful platform to tune their emission color. In this personal account, we put a special emphasis on our contributions to the novel color-tuning strategies in these heteroleptic ppy-type Ir(III) and Pt(II) complexes. In addition, afforded by our novel color-tuning strategies, ambipolar character or enhanced electron injection/transport (EI/ET) features can be furnished to bring high EL performances.

13.
Nano Lett ; 18(12): 7538-7545, 2018 12 12.
Artículo en Inglés | MEDLINE | ID: mdl-30480455

RESUMEN

Nanostructuring is an extremely promising path to high-performance thermoelectrics. Favorable improvements in thermal conductivity are attainable in many material systems, and theoretical work points to large improvements in electronic properties. However, realization of the electronic benefits in practical materials has been elusive experimentally. A key challenge is that experimental identification of the quantum confinement length, below which the thermoelectric power factor is significantly enhanced, remains elusive due to lack of simultaneous control of size and carrier density. Here we investigate gate-tunable and temperature-dependent thermoelectric transport in γ-phase indium selenide (γ-InSe, n-type semiconductor) samples with thickness varying from 7 to 29 nm. This allows us to properly map out dimension and doping space. Combining theoretical and experimental studies, we reveal that the sharper pre-edge of the conduction-band density of states arising from quantum confinement gives rise to an enhancement of the Seebeck coefficient and the power factor in the thinner InSe samples. Most importantly, we experimentally identify the role of the competition between quantum confinement length and thermal de Broglie wavelength in the enhancement of power factor. Our results provide an important and general experimental guideline for optimizing the power factor and improving the thermoelectric performance of two-dimensional layered semiconductors.

14.
J Am Chem Soc ; 139(19): 6718-6725, 2017 05 17.
Artículo en Inglés | MEDLINE | ID: mdl-28430435

RESUMEN

The long-term chemical instability and the presence of toxic Pb in otherwise stellar solar absorber APbX3 made of organic molecules on the A site and halogens for X have hindered their large-scale commercialization. Previously explored ways to achieve Pb-free halide perovskites involved replacing Pb2+ with other similar M2+ cations in ns2 electron configuration, e.g., Sn2+ or by Bi3+ (plus Ag+), but unfortunately this showed either poor stability (M = Sn) or weakly absorbing oversized indirect gaps (M = Bi), prompting concerns that perhaps stability and good optoelectronic properties might be contraindicated. Herein, we exploit the electronic structure underpinning of classic Cu[In,Ga]Se2 (CIGS) chalcopyrite solar absorbers to design Pb-free halide perovskites by transmuting 2Pb to the pair [BIB + CIII] such as [Cu + Ga] or [Ag + In] and combinations thereof. The resulting group of double perovskites with formula A2BCX6 (A = K, Rb, Cs; B = Cu, Ag; C = Ga, In; X = Cl, Br, I) benefits from the ionic, yet narrow-gap character of halide perovskites, and at the same time borrows the advantage of the strong Cu(d)/Se(p) → Ga/In(s/p) valence-to-conduction-band absorption spectra known from CIGS. This constitutes a new group of CuIn-based Halide Perovskite (CIHP). Our first-principles calculations guided by such design principles indicate that the CIHPs class has members with clear thermodynamic stability, showing direct band gaps, and manifesting a wide-range of tunable gap values (from zero to about 2.5 eV) and combination of light electron and heavy-light hole effective masses. Materials screening of candidate CIHPs then identifies the best-of-class Rb2[CuIn]Cl6, Rb2[AgIn]Br6, and Cs2[AgIn]Br6, having direct band gaps of 1.36, 1.46, and 1.50 eV, and theoretical spectroscopic limited maximal efficiency comparable to chalcopyrites and CH3NH3PbI3. Our finding offers a new routine for designing new-type Pb-free halide perovskite solar absorbers.

15.
Phys Chem Chem Phys ; 18(2): 1326-40, 2016 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-26658552

RESUMEN

By means of first-principles DFT computations, we systematically investigate the geometries, stabilities, electronic and magnetic properties of fully and partially hydrogenated zigzag BNC nanoribbons (fH-zBNCNRs and pH-zBNCNRs) with interfacial N-C or B-C connections. It is revealed that in the lowest-lying configuration of hybrid fH-zBNCNRs, the constituent C and BN segments can possess respective chair and boat conformations and both of them are connected by the chair mode, independent of the N-C/B-C interface. Changing the ribbon width and the ratio of BN to C can endow these fH-zBNCNR systems with abundant electronic and magnetic properties involving nonmagnetic (NM) semiconductivity, ferromagnetic (FM) metallicity, antiferromagnetic (AFM) metallicity as well as AFM half-metallicity. Besides, manipulating the hydrogenation pattern and ratio can also result in rich electronic and magnetic behaviors in pH-zBNCNRs, where NM semiconductivity, AFM semiconductivity, AFM metallicity and even AFM spin gapless semiconductor are observed. Additionally, the origin of the magnetism in these hydrogenated zBNCNRs is analyzed in detail. Finally, all of these hydrogenated BNC structures can possess a favorable formation energy, large binding energy per hydrogen atom and high thermal stability, indicating the great possibility of their experimental realization by hydrogenating pristine zBNCNRs. These valuable insights can be advantageous for promoting hybrid BNC-based nanomaterials in the applications of spintronics and multifunctional nanodevices.

16.
Angew Chem Int Ed Engl ; 55(38): 11442-6, 2016 09 12.
Artículo en Inglés | MEDLINE | ID: mdl-27529769

RESUMEN

A facile synthetic route is presented that produces a porous Ga-In bimetallic oxide nanophotocatalyst with atomically thin pore walls. The material has an unprecedented electronic structure arising from its ultrathin walls. The bottom of the conduction band and the top of the valence band of the material are distributed on two opposite surfaces separated with a small electrostatic potential difference. This not only shortens the distance by which the photogenerated charges travel from the sites where they are generated to the sites where they catalyze the reactions, but also facilitates charge separations in the material. The porous structure within the walls results in a large density of exposed surface reactive/catalytic sites. Because of these optimized electronic and surface structures, the material exhibits superior photocatalytic activity toward the hydrogen evolution reaction (HER).

17.
J Am Chem Soc ; 137(44): 14023-6, 2015 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-26352297

RESUMEN

Elaborate design of highly active and stable catalysts from Earth-abundant elements has great potential to produce materials that can replace the noble-metal-based catalysts commonly used in a range of useful (electro)chemical processes. Here we report, for the first time, a synthetic method that leads to in situ growth of {2̅10} high-index faceted Ni3S2 nanosheet arrays on nickel foam (NF). We show that the resulting material, denoted Ni3S2/NF, can serve as a highly active, binder-free, bifunctional electrocatalyst for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Ni3S2/NF is found to give ∼100% Faradaic yield toward both HER and OER and to show remarkable catalytic stability (for >200 h). Experimental results and theoretical calculations indicate that Ni3S2/NF's excellent catalytic activity is mainly due to the synergistic catalytic effects produced in it by its nanosheet arrays and exposed {2̅10} high-index facets.

18.
Phys Chem Chem Phys ; 17(37): 24038-47, 2015 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-26312553

RESUMEN

On the basis of first-principle computations, we first propose a simple and effective strategy through surface-adsorbing a poly(vinylidene fluoride) (PVDF) polymer via noncovalent interactions to tune the electronic and magnetic behaviors of zigzag SiC nanoribbons (zSiCNRs). It is revealed that depositing the strong electron-withdrawing PVDF polymer with a permanent dipole moment can induce the evident change of the electrostatic potential in the substrate zSiCNRs, like applying an electric field. As a result, this kind of noncovalent surface-modification by a polymer can break the magnetic degeneracy of zSiCNRs independent of the adsorption type and position, and sole ferromagnetic metallicity and even antiferromagnetic half-metallicity can be achieved. Moreover, all PVDF-modified zSiCNR systems can exhibit considerable adsorption energies in the range of -0.436 to -1.315 eV, indicating that these joint systems possess high structural stabilities. These intriguing findings will be advantageous for promoting excellent SiC-based nanomaterials in the applications of spintronics and multifunctional nanodevices in the near future.

19.
Phys Chem Chem Phys ; 17(2): 941-50, 2015 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-25407886

RESUMEN

By means of first-principles computations, we first propose a simple and effective strategy through the molecular charge transfer via noncovalent π-π interaction to modulate the electronic and magnetic properties of zigzag SiC nanoribbons (zSiCNRs). This charge transfer is induced by adsorbing the electron-withdrawing/donating tetracyanoquinodimethane (TCNQ) or tetrathiafulvalene (TTF) molecules on the surface of the pristine zSiCNR. It is revealed that all the TCNQ- and TTF-modified zSiCNR-systems can exhibit considerable adsorption energies in the range from -137.2 to -184.0 kJ mol(-1) and from -71.3 to -76.9 kJ mol(-1), respectively, indicating that these zSiCNR-complexes possess high structure stabilities. This kind of a molecular charge transfer via π-π interaction can break the magnetic degeneracy of zSiCNRs, and the sole ferromagnetic (FM) metallicity and even antiferromagnetic (AFM) half-metallicity can be achieved. These intriguing findings will be advantageous for promoting SiC-based nanomaterials in the application of spintronics and multifunctional nanodevices in the near future.

20.
Angew Chem Int Ed Engl ; 54(37): 10752-7, 2015 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-26212796

RESUMEN

In our efforts to obtain electrocatalysts with improved activity for water splitting, meticulous design and synthesis of the active sites of the electrocatalysts and deciphering how exactly they catalyze the reaction are vitally necessary. Herein, we report a one-step facile synthesis of a novel precious-metal-free hydrogen-evolution nanoelectrocatalyst, dubbed Mo2 C@NC that is composed of ultrasmall molybdenum carbide (Mo2 C) nanoparticles embedded within nitrogen-rich carbon (NC) nanolayers. The Mo2 C@NC hybrid nanoelectrocatalyst shows remarkable catalytic activity, has great durability, and gives about 100 % Faradaic yield toward the hydrogen-evolution reaction (HER) over a wide pH range (pH 0-14). Theoretical calculations show that the Mo2 C and N dopants in the material synergistically co-activate adjacent C atoms on the carbon nanolayers, creating superactive nonmetallic catalytic sites for HER that are more active than those in the constituents.

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