Chemical Physics Letters最新文献

The development of earth-abundant transition-metal-based electrocatalysts for hydrogen evolution reaction (HER) is commercial. In this work, Fe (Co) and Ni hydroxide nanocomposites on Ni foam were synthesized as HER catalyst, FeNi-LDH/NF has the overpotentials of 291 mV at 50 mA cm⁻² and 369 mV at 100 mA cm⁻². It is found that FeNi-LDH/NF and CoNi-LDH/NF have large C_dl and ECSA, low R_ct. Therefore, this simple method to prepare FeNi-LDH/NF and CoNi-LDH/NF can enhance the properties of electrocatalysts, which make FeNi-LDH/NF and CoNi-LDH/NF a promising material to replace noble metal-based catalysts.

The unpredictable nature of the interaction of water molecules with carbon surfaces is evident in the wide-ranging behavior observed in simple macroscopic observations such as contact angle. Complex fluid–solid and fluid–fluid interactions can convolute the observed behavior and when coupled with confinement at the nanoscale, large deviations might be expected in predictions via macroscopic properties. However, by delivering a quantitative description of water adsorption in microporous carbon, this study demonstrates that macroscopic features can predict nanoscale behavior of confined water. Furthermore, through introduction of nanocapillarity and nanowetting, an Ising-Model-Modified-Kelvin Analysis (IMMKA) for water adsorption is proposed, interpreted and validated.

In this work, one-pot Zinc-based metal–organic framework ternary composite was prepared with polypyrrole and reduced graphene oxide (rGO/Ppy/Zn-MOF) for high-performance supercapacitor. The as-prepared rGO/Ppy/Zn-MOF composite showed outstanding electrochemical properties. In energy storage application, synthesized rGO/Ppy/Zn-MOF showed excellent specific capacitance, i.e., 175F/g at 1 A/g current density, specific energy i.e. 19.68 Wh kg⁻¹, and specific power of 1792 W kg⁻¹. With cyclic stability at 10 A/g, retaining up to 82 % of its initial capacitance after more than 7000 repetitive charge–discharge cycles. These findings may help to accelerate the development of high-performance supercapacitor.

The electronic structure, dynamic, thermal, and optical characteristics of a hexagonal pure XS (where X = Be, Mg, Ca and Sr) monolayer are studied using DFT. These monolayers are structurally and thermally stable, according to AIMD simulations. At 300 K, there is no structural deformation, indicating XS monolayers are generally stable and preserved. Both BeS and MgS have indirect band gaps, but CaS and SrS have direct band gaps. The optical behaviors have been found to be anisotropic in the light polarized along the parallel directions. These results justify the usage of XS monolayers in thermal, photodetectors and other nanodevice applications.

We used DFT simulations to study the electronic and optical properties of a 2D crystal called 2D Diboron-Porphyrin (2DDP). Our results show that strain can tune 2DDP’s electronic properties from semiconducting to metallic, depending on strain direction. The unstrained system has a 0.6 eV band gap, which increases with strain perpendicular to the BB bond, while parallel strain induces metallic behavior. Additionally, 2DDP’s optical activity spans from infrared to ultraviolet and can be strain-tuned, highlighting its potential for electro-opto-mechanical applications.

Regulated DNA-binding ligands can be employed to design fluorescent probes and new drugs for promising chemical and biological applications. However, predicting the binding affinities of DNA ligands based on energy and geometry remains a challenge. In this work, combined molecular docking, molecular dynamics (MD) simulation, and generalized energy-based fragmentation (GEBF) approaches were performed to predict the three binding complexes between DNA and fluorescent or drug molecules. The GEBF binding energy calculation finds that the predicted optimal complexes would agree with the experimental ones in a minor-groove binder, which is more accurate and effective than molecular mechanics and semi-empirical quantum mechanics. The binding site of the water molecule around DAPI-DNA, which forms hydrogen bond networks with the DAPI ligand, can also be predicted with the GEBF method. The result show that the predicted absorption spectra are closely match the experimental measures when considering the solvent, electrostatic, and polarization interactions. Thus, the theoretical calculations using docking, MD simulations, and GEBF methods can be applied to predict the binding modes and sites of DNA ligands, suggesting that it is helpful for virtual screening and designing new small ligands to recognize DNA with various applications.

Various techniques have been devised so far to enhance cancer treatment efficacy and address drug conflicts. We explored Borophene (B₃₆) as a nanocarrier for the anti-cancer drugs carmustine (CMT) and nitrosourea (NU) in vacuum and liquid phases using density functional theory. Both drugs were placed at perpendicular and parallel positions of B₃₆ and the adsorption energies of – 2.83, and −3.28 eV for CMT and NU respectively. The parallel site was found good due to higher adsorption energy than the perpendicular site. We examine the structural stability, electronic properties, adsorption properties work function ($\phi$), recovery time ($\tau$), and universal signifiers of the CMT and NU drugs for both configurations. Hirshfeld and DOS analysis shows that the drug acts as a donor of electrons to the B₃₆ sheet in the configurations studied. Computed results show that, compared to perpendicular configurations, the parallel configurations of CMT and NU exhibit better performance, with shorter recovery times at body temperature. We have confirmed the water solubility of both drugs and their distribution. We have verified that the drugs interact effectively with the amino acids without causing any damage to the protein. Additionally, our calculations indicate that in the slightly acidic environment of tumor tissue, CMT and NU drugs could begin to release from the B₃₆ surface without causing significant changes to the structural properties. The findings of this study indicated that, between the two drugs, CMT is likely to be used as a nanocarrier for B₃₆, while NU/ B₃₆ is an extremely hopeful biological carrier for drug delivery purposes.

This paper explores methods to enhance salt pumping efficiency in synthetic nanochannels. Molecular dynamics simulations investigate rectangular nanochannel connecting reservoirs, employing an external oscillating potential while maintaining zero net potential. Different channel shapes, including pyramidal and ratchet designs, are studied, with ratchet channels demonstrating superior ion pumping efficiency. Simulations further analyze ion pumping in ratchet channels under varying ionic concentrations and applied voltages showing decreased efficiency with higher initial concentrations but improved efficiency with increased external potential. The research emphasizes the importance of channel geometry, initial concentration, applied potentials, and oscillation period in optimizing ion transport for nanoscale applications.

The research for coating materials with low coefficient of friction, low wear rate, and high strength is important for industrial lubrication and protection. This study provides an approach of double-layer coating as protective coating, with carbon nanotube (CNT) and polyether ether ketone (PEEK) as reinforcing nano-fillers. The mechanical and frictional properties of four types of single layers were investigated for the selection of top layer. The selection of bottom layer was based on the adhesion between the coat and the substrate. According to the analysis results, the molecular models of CNT and PEEK reinforced EP layer and pure EP layer were applied as top and bottom layers of a coating, respectively, named as EP-PEEK/CNT/EP coating. For comparison, a pure EP double-layer coating (named as the EP-EP coating) was developed. The friction and wear of these two coatings against a Cu counter friction partner were observed from the atomic scale using molecular dynamics (MD) simulation. The coefficients of friction were analyzed by extracting the relative atomic concentrations and relative atomic velocities of the coatings along the Z-direction during shear, while the friction losses were analyzed using the values of mean-square displacement (MSD) function and radial distribution function (RDF). The simulation results showed that the stronger interaction force between PEEK/CNT and EP molecules led to a lower coefficient of friction and reduced friction loss for the EP matrix of the coating. Additionally, the use of pure epoxy resin as the bottom layer ensured stronger adhesion to the substrate.

This study introduces a novel biosensor based on a glassy carbon electrode (GCE) modified with nanogold and glucocorticoid receptors (GR) for the sensitive and selective detection of glucocorticoids. The biosensor employs a sensing methodology that capitalizes on the specific adsorption of glucocorticoid molecules to the GR-modified electrode surface, forming a sandwich complex structure that impedes electron transfer, detectable by differential pulse voltammetry (DPV). Electrochemical characterization through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated enhanced electron transfer rates and the effects of electrode surface modifications on the biosensor’s performance. Optimization studies identified ideal conditions for GR concentration and incubation time, enhancing the biosensor’s immune response and detection efficiency. The biosensor exhibited outstanding detection capabilities for six glucocorticoids, with a detection limit ranging from 0.012 to 0.065 ng⋅mL⁻¹ and a broad linear range of 0.1 to 1000 ng⋅mL⁻¹. Its performance surpassed conventional detection methods, attributing to the conductivity and nanoscale effects of nanogold. Repeatability and stability assessments confirmed the biosensor’s reliability and potential for practical applications. Analysis of actual skincare samples further validated the biosensor’s effectiveness in real-world scenarios, demonstrating high accuracy and recovery rates. The study underscores the biosensor’s potential as a robust tool for environmental analysis, food safety, clinical diagnosis, and on-site glucocorticoid detection, offering significant advantages in terms of cost-effectiveness, portability, and response time.