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 H2 fuel generation, solidification for living-organism cryopreservation, structure stiffening for bioengineering, etc., with mechanisms being still puzzling. We show that the framework of “hydrogen bonding and electronic dynamics” has substantiated the progress in the fundamental issues and the aimed engineering. The segmental disparity of the coupled hydrogen bond (O:HO or HB with “:” being lone pair of oxygen) resolves their specific-heat curves and turns out a quasisolid phase (QS, bound at −15 and 4 °C). Electrification shows dual functionality that not only aligns, orders, polarizes water molecules but also stretches the O:HO bond. The O:HO segmental cooperative relaxation and polarization shift the QS boundary through Einstein's relation, ΔΘDx ∝ Δωx, resulting in a gel-like, viscoelastic, and stable supersolid phase with raised melting point Tm and lowered temperatures for vaporization TV and ice nucleation TN. The supersolidity and electro structure ordering provide additional forces to reinforce Armstrong's water bridge. QS dispersion and the secondary effect of electrification such as compression define the TN for Dufour's electro-freezing. The TV depression, surface stress disruption, and electrostatic attraction raise Asakawa's molecular evaporability. Composition of opposite, compatible fields eases the HO dissociation and soil wetting. Progress evidences not only the essentiality of the coupled O:HO bond theory but also the feasibility of engineering water and solutions by programmed electrification.
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•Electrification shows dual functionality on anisotropic structure ordering and phase stability•Electrification raises the Tm and lowers the TN and TV through O:HO bond relaxation•Surface stress disruption, TV depression, and electrostatic attraction ensure Asakawa's evaporation•Supersolid viscoelasticity, raised Tm and depressed TN entitle Armstrong's floating bridge•Water skin electric-double-layer stabilize fogs and clouds from being separating or agglomerating
With the miniaturization of a solid, effects of surface strain and quantum trapping become increasingly important in determining its properties. As a result, low-dimensional materials manifest ...unusual features, especially in their energetic and mechanical behavior. The establishment of a consistent understanding on an atomic-level of the mechanism behind the fascinating behaviors of low-dimensional systems, which include monatomic chains, hollow tubes, liquid and solid surface skins, nanocavities, nanowires, and nanograins, as well as interfaces, has long been a great challenge. In this report, a literature survey is presented, followed by a theoretical analysis culminating in the development of a local bond average (LBA) approach that may complement existing approximations in terms of continuum medium and quantum computations. The LBA approach correlates the measurable quantities of a specimen to the identities of its representative bonds, and the energetic responses of these bonds (bond nature, order, length and strength) to external stimuli, such as changes in temperatures and coordination environments. It is shown that the shortened and strengthened bonds between under-coordinated atoms and the consequent local strain and quantum trapping dictate, intrinsically, the mechanical behavior of systems with a high proportion of such atoms. The thermally driven softening of a substance arises from bond expansion and lattice vibrations that weaken the bonds. The competition between the energy density gain and the residual atomic cohesive energy in the relaxed surface of skin depth determines,
intrinsically, the mechanical performance of a mesoscopic specimen; the competition between the activation and inhibition of the motion of atomic dislocations motion dominates,
extrinsically, the yield strength of the specimen during plastic deformation. Therefore, the mechanical behavior of a specimen depends on its shape, size, the nature of the bonds involved, surface and interface conditions, and the temperature at which the physical properties of the specimen is measured. Excellent agreement with existent measurements of temperature dependence of surface tension, size and temperature dependence of elasticity and extensibility, and the inverse Hall–Petch relationship in nanograins have been established. Furthermore, these agreements have led to quantitative information regarding the bond identities in monatomic chains and carbon nanotubes, as well as the factors dominating the sizes at which a grain is strongest. In addition, the interface electric repulsion between nanocontacts due to the skin trapping and the associated local charge densification may provide feasible mechanism for the superfluidity, superlubricity and superhydrophobicity as widely observed. The progress made insofar evidences the essentiality of the LBA approach from the perspective of bond formation, dissociation, relaxation and vibration and the associated energetics for the exposition of thermo-mechanical behavior of low-dimensional materials. Extending the application of the approach to junction interfaces, liquid surfaces, defects and impurities, chemically adsorbed systems, amorphous states, and substances under other applied stimuli such as pressure and electric field would contribute to better knowledge of such systems and could lead to the development of even more fascinating and profitable materials.
Heteroatom doping is known as an effective strategy to improve the electrochemical performance of carbon materials. In this work, phosphorus (P)-doped carbon nanofiber aerogels (P-CNFA) were prepared ...from bacterial cellulose via freeze-drying and thermal treatment. The structure and electrochemical characterizations show that P-CNFA exhibit a porous, interconnected, well-organized 3D network structure and P doping can enhance the specific surface area, facilitate the charge transfer, and thus improve the specific capacitance and electrosorption capacity of CNFA. Especially, the electrosorption capacity of P-CNFA can reach up to a high value of 16.20 mg g−1 in 1000 mg L−1 NaCl solution, much higher than that of undoped CNFA (12.81 mg g−1). These results indicate that P-CNFA should be a promising candidate for capacitive deionization application.
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Although they exist ubiquitously in human bodies and our surroundings, the impact of nonbonding lone electrons and lone electron pairs has long been underestimated. Recent progress demonstrates that: ...(i) in addition to the shorter and stronger bonds between under-coordinated atoms that initiate the size trends of the otherwise constant bulk properties when a substance turns into the nanoscale, the presence of lone electrons near to broken bonds generates fascinating phenomena that bulk materials do not demonstrate; (ii) the lone electron pairs and the lone pair-induced dipoles associated with C, N, O, and F tetrahedral coordination bonding form functional groups in biological, organic, and inorganic specimens. By taking examples of surface vacancy, atomic chain end and terrace edge states, catalytic enhancement, conducting-insulating transitions of metal clusters, defect magnetism, Coulomb repulsion at nanoscale contacts, Cu
3
C
2
H
2
and Cu
3
O
2
surface dipole formation, lone pair neutralized interface stress,
etc
, this article will focus on the development and applications of theory regarding the energetics and dynamics of nonbonding electrons, aiming to raise the awareness of their revolutionary impact to the society. Discussion will also extend to the prospective impacts of nonbonding electrons on mysteries such as catalytic enhancement and catalysts design, the density anomalies of ice and negative thermal expansion, high critical temperature superconductivity induced by B, C, N, O, and F, the molecular structures and functionalities of CF
4
in
anti
-coagulation of synthetic blood, NO signaling, and enzyme telomeres,
etc
. Meanwhile, an emphasis is placed on the necessity and effectiveness of understanding the properties of substances from the perspective of bond and nonbond formation, dissociation, relaxation and vibration, and the associated energetics and dynamics of charge repopulation, polarization, densification, and localization. Finding and grasping the factors controlling the nonbonding states and making them of use in functional materials design and identifying their limitations will form, in the near future, a subject area of "nonbonding electronics and energetics", which could be even more challenging, fascinating, promising, and rewarding than dealing with core or valence electrons alone.
The impact of nonbonding lone-electron pairs and lone pair-induced dipoles associated with N, O and F tetrahedral coordination bonding and the broken-bond-induced local bond contraction (
d
i
<
d
0
), quantum entrapment (T), and polarization of the nonbonding lone electrons (P) associated with atomic under-coordination is demonstrated.
Aqueous charge injection in forms of electrons, protons, lone pairs, ions, and molecular dipoles by solvation is ubiquitously important to our health and life. Pursuing fine-resolution detection and ...consistent insight into solvation dynamics and solute capabilities has become an increasingly active subject. This treatise shows that charge injection by solvation mediates the O:H-O bonding network and properties of a solution through O:H formation, H↔H fragilization, O:⇔:O compression, electrostatic polarization, H
2
O dipolar shielding, solute-solute interaction, and undercoordinated H-O bond contraction. A combination of the hydrogen bond (O:H-O or HB with ':' being the electron lone pairs of oxygen) cooperativity notion and the differential phonon spectrometrics (DPS) has enabled quantitative information on the following: (i) the number fraction and phonon stiffness of HBs transiting from the mode of ordinary water to hydration; (ii) solute-solvent and solute-solute molecular nonbond interactions; and (iii) interdependence of skin stress, solution viscosity, molecular diffusivity, solvation thermodynamics, and critical pressures and temperatures for phase transitions. An examination of solvation dynamics has clarified the following: (i) the excessive protons create the H↔H or anti-HB point breaker to disrupt the acidic solution network and surface stress. (ii) The excessive lone pairs generate the O:⇔:O or super-HB point compressor to shorten the O:H nonbond but lengthen the H-O bond in H
2
O
2
and basic solutions; yet, bond-order-deficiency shortens and stiffens the H-O bond due H
2
O
2
and OH
−
solutes. (iii) Ions serve each as a charge center that aligns, clusters, stretches, and polarizes their neighboring HBs to form hydration shells. (iv) Solvation of alcohols, aldehydes, complex salts, carboxylic and formic acids, glycine, and sugars distorts the solute-solvent interface structures with the involvement of the anti-HB or the super-HB. Extending the knowledge and strategies to catalysis, solution-protein, drug-cell, liquid-solid, colloid-matrix interactions and molecular crystals would be even more fascinating and rewarding.
Two experiments were conducted to investigate the immune‐enhancing effect of dietary supplement with Astragalus polysaccharides (APS) on the Pacific white shrimp, Litopenaeus vannamei. In experiment ...1, the optimal APS dose was determined based on the immune responses of shrimps fed APS diet for 30 days. In experiment 2, the effect of APS supplementation on immune response of shrimp suffering white spot syndrome virus (WSSV) challenge was determined. Results showed that the total haemocyte count and phagocytic activity in shrimps fed APS diets significantly (p < .05) increased in comparison with those fed the basal diet. Dietary supplement with APS markedly (p < .05) increased the activity of phenoloxidase (PO), total superoxide dismutase (SOD), lysozyme (LZM), acid phosphatase and alkaline phosphatase in shrimp hemolymph, but decreased the maleic dialdehyde (MDA) content. Significantly higher (p < .05) activity on PO, SOD and LZM and lower (p < .05) MDA content have also been found in shrimps suffering WSSV challenge. Therefore, APS could be used as a safe and effective feed additive in shrimp aquaculture, and the optimal dose of APS for the Pacific white shrimp was suggested to be 0.2 g/kg based on our results.
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•A novel system combining photocatalysis and capacitive deionization is proposed.•The system is used to effectively remove the total Cr from the aqueous solution.•Effective removal of ...the total Cr with a high removal ratio of 72.2% is achieved.
A novel system combining photocatalysis and capacitive deionization (CDI) was proposed and used to efficiently remove the total Cr from the aqueous solution for the first time. MIL-53(Fe) with wide visible-light absorption was successfully prepared by a simple solvothermal method, and applied as positive photoelectrode material of the photocatalysis-CDI system (PCS) to convert Cr(VI) to Cr(III). Active carbon was used as negative electrode material to absorb Cr(III). An enhanced removal of Cr(VI) can be obtained by applying visible light irradiation and 1.3 V direct current (DC) voltage simultaneously and the Cr(VI) removal can reach a maximum value of 81.6%, much higher than those under individual 1.3 V DC voltage (39.4%) or visible light irradiation (54.2%), demonstrating the synergistic effect from CDI and photocatalysis. More importantly, effective removal of the total Cr with high removal ratio (72.2%) can be achieved, which is difficult to be realized using current other technologies. The strategy in this work provides a promising method for the complete removal of high-valence heavy metal ions.
Considering the flexible chemical composition, tunable electronic properties and unique two-dimensional structure of layered double hydroxides (LDHs), we constructed NiFe-LDH/Cu2O heterostructure ...photocatalysts. The photocatalytic performance of NiFe-LDH/Cu2O heterostructure photocatalysts was evaluated by methyl blue (MB) degradation and CO2 reduction under visible-light illumination. The removal efficiency of MB was improved from 20% for Cu2O and 45% for NiFe-LDH to 93% for NiFe-LDH/Cu2O after 30 min adsorption and 240 min visible-light irradiation. Moreover, CH4 yield from CO2 reduction over NiFe-LDH/Cu2O is about 5.6 and 6.9 times that of NiFe-LDH and Cu2O, respectively. Based on a detailed study of structural, electronic, optical and electrochemical properties, Z-scheme photocatalytic mechanism was proposed to explain the enhanced photocatalytic performance of NiFe-LDH/Cu2O. This work presents an inexpensive and flexible strategy for manufacturing heterostructure photocatalysts using earth-abundant elements.
•NiFe-LDH/Cu2O heterostructure photocatalysts were successfully prepared by a co-precipitation method.•MB removal efficiency can be improved from 20% for Cu2O and 45% for NiFe-LDH to 93% for NiFe/Cu2O。.•CH4 yield from CO2 photoreduction over NiFe-LDH/Cu2O is 5.6 and 6.9 times of NiFe-LDH and Cu2O, respectively.•Z-scheme mechanism is proposed, which is responsible for promoted charge separation and higher redox potentials.
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