Hydrogen Bonding Polarization Strengthening the Peptide-Based Hydrogels.

Peptide-based hydrogels form a kind of promising material broadly used in biomedicine and biotechnology. However, the correlation between their hydrogen bonding dynamics and mechanical properties remains uncertain. In this study, we found that the adoption of β-sheet and α-helix secondary structures by ECF-5 and GFF-5 peptides, respectively, could further form fiber networks to immobilize water molecules into hydrogels.

Retraction: Unprecedented O:⇔:O compression and H↔H fragilization in Lewis solutions.

Retraction of 'Unprecedented O:⇔:O compression and H↔H fragilization in Lewis solutions' by Chang Q. Sun, , 2019, , 2234-2250, https://doi.org/10.

Correction: Supersolidity of undercoordinated and hydrating water.

Correction for 'Supersolidity of undercoordinated and hydrating water' by Chang Q. Sun, , 2018, , 30104-30119, https://doi.org/10.

Nonbonding Electron Delocalization Stabilizes the Flexible N Molecular Assembly.

Electron delocalization has an important impact on the physical properties of condensed materials. However, the L-electron delocalization in inorganic, especially nitrogen, compounds needs exploitation to improve the energy efficiency, safety, and environmental sustainability of high-energy-density materials (HEDMs). This Letter presents an intriguing N molecule, ingeniously utilizing nitrogen's L-electron delocalization.

Discriminative Mechanical and Thermal Response of the H-N Bonds for the Energetic LLM-105 Molecular Assembly.

Molecular interactions in energetic materials form the key not only to the "structure stability, energy storage, ignition, and detonation" dynamics but also to the sensitivity to the loading of perturbation and the power intensity of radiation for the energetic substance, with the nature of the interactions remaining elusive. With the aid of perturbative Raman spectroscopy and the pressure-resolved density functional theory, we uncovered that the H-N bond of the intermolecular O:H-N bonds for LLM-105 shares the same negative compressibility and thermal expansivity of the H-O bond for the coupling O:H-O bond of water [ , 998, 1-68]. In contrast, the dangling H-N bond vibrating at a 3440 cm high frequency does otherwise due to the absence of coupling interaction and the undercoordination-driven bond contraction.

Perturbative vibration of the coupled hydrogen-bond (O:H-O) in water.

Perturbation Raman spectroscopy has underscored the hydrogen bond (O:H-O or HB) cooperativity and polarizability (HBCP) for water, which offers a proper parameter space for the performance of the HB and electrons in the energy-space-time domains. The OO repulsive coupling drives the O:H-O segmental length and energy to relax cooperatively upon perturbation. Mechanical compression shortens and stiffens the O:H nonbond while lengthens and softens the HO bond associated with polarization.

Designing of Highly Efficient Oxygen Evolution Reaction Electrocatalysts Utilizing A Correlation Factor: Theory and Experiment.

The theoretical prediction of the catalytic activity is very beneficial for the design of highly efficient catalysts. At present, most theoretical descriptors focus on estimating the catalytic activity and understanding the enhancement mechanism of catalysts, while it is also quite important to find a factor to correlate the descriptors with preparation methods. In this work, a correlation factor, the d electron density of transition metal ions, was developed to correlate the d band center values of transition metal ions with the preparation methods of amorphization and Al introduction.

Applying machine learning to balance performance and stability of high energy density materials.

The long-standing performance-stability contradiction issue of high energy density materials (HEDMs) is of extremely complex and multi-parameter nature. Herein, machine learning was employed to handle 28 feature descriptors and 5 properties of detonation and stability of 153 HEDMs, wherein all 21,648 data used were obtained through high-throughput crystal-level quantum mechanics calculations on supercomputers. Among five models, namely, extreme gradient boosting regression tree (XGBoost), adaptive boosting, random forest, multi-layer perceptron, and kernel ridge regression, were respectively trained and evaluated by stratified sampling and 5-fold cross-validation method.

Structure and Stability of Aromatic Nitrogen Heterocycles Used in the Field of Energetic Materials.

Understanding the stabilization of nitrogen heterocycles is critical in the field of energetic materials and calls for innovative knowledge of nitrogen aromatics. Herewith, we report for the first time that nitrogen lone pair electron (NLPE) delocalization in five-membered nitrogen heterocycles creates a second σ-aromaticity in addition to the prototypical π-aromaticity. The NLPE delocalization and the attendant dual-aromaticity are enhanced as more carbon atoms in the ring are substituted by unsaturated nitrogen atoms.

Water electrification: Principles and applications.

Deep engineering of liquid water by charge and impurity injection, charged support, current flow, hydrophobic confinement, or applying a directional field has becoming increasingly important to the mankind toward overcoming energy and environment crisis. One can mediate the processes or temperatures of molecular evaporation for clean water harvesting, HO bond dissociation for H fuel generation, solidification for living-organism cryopreservation, structure stiffening for bioengineering, etc., with mechanisms being still puzzling.

Strategies for Achieving Balance between Detonation Performance and Crystal Stability of High-Energy-Density Materials.

Performance-stability contradiction of high-energy-density materials (HEDMs) is a long-standing puzzle in the field of chemistry and material science. Bridging the gap that exists between detonation performance of new HEDMs and their stability remains a formidable challenge. Achieving optimal balance between the two contradictory factors is of a significant demand for deep-well oil and gas drilling, space exploration, and other civil and defense applications.

Unexpected Solute Occupancy and Anisotropic Polarizability in Lewis Basic Solutions.

Density functional computation revealed that in YOH solvation (Y = Li, Na, and K), the Y cation locates eccentrically at the interstitial hollow site to form the Y·4HO unit, and the hydroxyl adds an excessive electron lone pair ":" to form a OH·HO unit where the hydroxide stays in the the center. The surrounding four oriented HO neighbors interact with the Y through Y ↔ H repulsion and Y:O attraction, causing the Y eccentric dislocation by some 0.80 Å.

Mechanism and Functionality of Pnictogen Dual Aromaticity in Pentazolate Crystals.

Our recent work (J. Phys. Chem.

Stabilization of the Dual-Aromatic cyclo-N Anion by Acidic Entrapment.

Pentazole anion, the best candidate for full-nitrogen energetic materials, can be isolated only from acidic solution for unclear reasons, which hinders the high-yield realization of a full-nitrogen substance with higher energy density. Herein, we report for the first time the discovery of the dual aromaticity (π and σ) of cyclo-N, which makes the anion unstable in nature but confers additional stability in acidic surroundings. In addition to the usual π-aromaticity, similar to that of the prototypical benzene, five lone pairs are delocalized in the equatorial plane of cyclo-N, forming additional σ-aromaticity.

Waste bones derived nitrogen-doped carbon with high micropore ratio towards supercapacitor applications.

Fabrication of high-performance electrodes from waste biomass has attracted increasing attention among the energy storage and conversion field. In this work, we have synthesized nitrogen-doped activated carbon by a simultaneous pyrolysis/activation method from waste bones. It is found that the specific surface area and pore structure of as-synthesized carbon depends on the carbonization temperature (500-800 °C), and the highest specific surface area is 1522 m g.

Hydration of Hofmeister ions.

Water dissolves salt into ions and then hydrates the ions to form an aqueous solution. Hydration of ions deforms the hydrogen bonding network and triggers the solution with what the pure water never shows such as conductivity, molecular diffusivity, thermal stability, surface stress, solubility, and viscosity, having enormous impact to many branches in biochemistry, chemistry, physics, and energy and environmental industry sectors. However, regulations for the solute-solute-solvent interactions are still open for exploration.

Electronic structure of two-dimensional In and Bi metal on BN nanosheets.

The electronic structures of two-dimensional (2D) indium (In) and bismuth (Bi) metal on BN nanosheets are systematically studied using hybrid density functional theory (DFT). We found that 2D In and Bi metal effectively modulate the band gap of a BN nanosheet. We also found that the indirect band gap of the 2D In and Bi metal electronic structures are 0.

Unprecedented O:⇔:O compression and H↔H fragilization in Lewis solutions.

Charge injection in terms of lone pairs ':', protons, and ions upon acid and base solvation mediates the hydrogen bonding network and properties of Lewis solutions, and is ubiquitously important in many subject areas of Chemical Physics. This work features the recent progress and future trends in this aspect with a focus on the solute-solvent interactions and hydrogen bond (O:H-O or HB) transition from the vibration mode of ordinary water to the hydrating states. A combination of the O:H-O bond cooperativity notion, differential phonon spectrometrics, calorimetric detection, and quantum computations clarified the solute capabilities of O:H-O bond transition in HX and YOH (X = Cl, Br, I and Y = Li, Na, K) solutions.

Supersolidity of undercoordinated and hydrating water.

Supersolidity of ice, which was proposed in 2013 and intensively verified since then [C. Q. Sun et al.

Arsenene nanoribbon edge-resolved strong magnetism.

We proposed a mechanism to induce strong magnetism of up to 10.92 emu g-1 in hexagonal-phase arsenene nanoribbon (AsNR) from the perspective of edge quantum entrapment. Consistency between bond-order-length-strength correlation (BOLS) theory and density functional theory (DFT) calculations verified that: (i) the edge bond contraction of 9.

Phonon Spectrometric Evaluation of the Solute-Solvent Interface in Solutions of Glycine and Its N-Methylated Derivatives.

From the perspective of O:H-O bond cooperativity, we analyzed the solute capability of transiting the O:H-O bond from the mode of ordinary water to the hydration state and its consequence on the solution viscosity and surface stress. Phonon spectrometric results suggest that glycine and its N-methyl derivatives strongly affect the surrounding solvent molecules through H ↔ H repulsion and dipolar polarization. The H ↔ H interproton repulsion disrupts the surface stress, and the polarization enhances the solution viscosity.

CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions.

The Band-Gap Modulation of Graphyne Nanoribbons by Edge Quantum Entrapment.

Using ab initio calculation coupled with the bond-order-length-strength (BOLS) approximation, we investigate the configurations and electronic properties of (, )-graphyne nanoribbons (GYNRs) with armchair (AGYNRs) and zigzag (ZGYNRs) edges. Our investigation shows that the armchair-edged -GYNRs and all -GYNRs are semiconductors with suitable band-gaps, and that their band-gaps increase as the widths of nanoribbons decrease; on the other hand, zigzag-edged -GYNRs appear to be zero-band-gap materials. Observation results suggest that (i) atomic undercoordination shortens and stiffens the C-C bond, which contributes to the Hamiltonian and hence widens the band-gap intrinsically; (ii) zigzag-edged -GYNRs lack a band-gap due to the edge-undercoordinated atoms lacking the energy to open the -graphyne gap; and (iii) the edge-undercoordination of atoms occurs during charge entrapment.

DFT Study on Intermetallic Pd-Cu Alloy with Cover Layer Pd as Efficient Catalyst for Oxygen Reduction Reaction.

Detailed density functional theory (DFT) calculations of the adsorption energies (E) for oxygen on monolayer Pd on top of the Pd-Cu face-centered cubic (FCC) alloy and intermetallic B2 structure revealed a linear correspondence between the adsorption energies and the -band center position. The calculated barrier (E) for oxygen dissociation depends linearly on the reaction energy difference (ΔE). The O₂ has a stronger adsorption strength and smaller barrier on the intermetallic Pd-Cu surface than on its FCC alloy surface.