Hydrogen cold plasma for synthesizing Pd/C catalysts: the effect of support-metal ion interaction

It has been found that cold plasma is a facile and environmentally benign method for synthesizing supported metal catalysts, and great efforts have been devoted to enlarging its applications. However, little work has been done to disclose the influence mechanism, which is significant for controllable synthesis. In this work, hydrogen cold plasma was adopted to synthesize a palladium catalyst supported on activated carbon （Pd/C-P） using HzPdC14 as a Pd precursor followed by calcination in hydrogen gas to remove the chlorine ions. The Pd/C-P catalyst was found to be made of larger Pd nanoparticles showing a decreased migration to the support outer surface than that prepared by the conventional thermal hydrogen reduction method （Pd/C-C）. Meanwhile, the pore diameter of the activated carbon support is small （,-~4 nm）. Therefore, Pd/C-P exhibits lower CO oxidation activity than Pd/C-C. It was proposed that the strong interaction between the activated carbon and PdC142-, and the enhanced metal-support interaction caused by hydrogen cold plasma reduction made it difficult for Pd nanoparticles to migrate to the support outer surface. The larger-sized Pd nanoparticles for Pd/C-P may be due to the Coulomb interaction resulting in the disturbance of the metal-support interaction. This work has important guiding significance for the controllable synthesis of supported metal catalysts by hydrogen cold plasma.

Study on the Complexation of Molybdenum（Ⅵ） with Iminodiacetic Acid and Ethylenediamine-N,N′-diacetic Acid by Specific Ion Interaction and Debye-Hückel Theories

Complexation of two ligands, iminodiacetic acid and ethylenediamine-N,N′-diacetic acid, with molybdenum（Ⅵ） was studied in aqueous solutions. Molybdenum（Ⅵ） forms a mononuclear complex with the aforementioned ligands of the type MoO3L^2-. All measurements have been carried out at 25 ℃ and different ionic strengths ranging from 0.1 to 1.0 mol·L^-1 of NaClO4, with the pH justified to 6.0. Equilibrium concentration products and stoichiometry of the complexes have been determined from a combination of potentiometric and UV spectroscopic measurements. Comparison of the ionic strength effect on these complex formation reactions has been made using a Debye-Hückel type equation and Bronsted-Guggenheim-Scatchard specific ion interaction theory （SIT）. Debye-Hückel theory predicted the first order effects on simple electrolyte solutions. Interactions between the reacting species and the ionic medium were taken into account in the SIT model. All of the calculations have been done by the computer program Excel 2000.

Interaction of ions in water system containing copper-zinc alloy for boiler energy saving

Copper-zinc alloy element for boiler energy saving was put in the intake of simulated boiler system to investigate the interaction and transfer of ions in water system both theoretically and experimentally. The fouling was analyzed by scanning electron microscopy (SEM) and energy dispersive X-ray detector (EDX). The results show that the transfer of calcium and magnesium ions in heat-transfer-surface-water system is affected by zinc ions dissolved from the alloy because of primary battery reaction. Some calcium ions of calcium carbonate crystal are replaced by zinc ions, the growth of aragonite crystal nucleus is retarded, and the transition of calcium carbonate from aragonite to calcite is hampered.

Interaction between Low Energy ions and the Complicated Organism

Low energy ions exist widely in natural world, but people pay a little attention on. the interaction between low energy ions and matter, it is even more out of the question of studying on the relation of low energy ions and the complicated organism. The discovery of bioeffect induced by ion implantation has, however, opened a new branch in the field of ion beam application in life sciences. This paper reports recent advances in research on the role of low energy ions in Chemical synthesis of the biomolecules and application in genetic modification.

CALORIMETRIC AND RAMAN SPECTROSCOPIC STUDIES ON THE INTERACTION OF LANTHANOID IONS WITH DIPALMITOYLPHOSPHATIDYLCHOLINE BILAYER

The interactions of lanthanoid ions with dipalmitoylphosphatidylcholine bilayer were studied by DSC and Raman spectroscopy.The results show that the addition of lanthanoid ions causes a considerable increase of the gel to liquid crystalline transition temperature of phospholipid and a reduction of order of lateral packing and conformation of acyl chains in SUVs.

INTERACTION MECHANISM OF AMPHOTERIC COLLECTOR-I WITH METALLIC IONS AND MINERALS

The electronic structure and bonding nature of adsorbing bonding complexes which consist of Amphoteric Collector-I and Mg^(2+), Ca^(2+), MgPO_4^-, CaPO_^-4, CaCO_3, as well aa MgCO_3, are studied using quantum chemistry CNDO/2, It is predicted that magnesium salts are more liable to form adsorbing chelates with Amphoteric Collector-I than calcium salts, and all results coincide with that obtained in flotation.

Effect of mono-/divalent metal ions on the conductivity characteristics of DNA solutions transferring through a microfluidic channel

Interactions between deoxyribonucleic acid(DNA) and metal ions are vital for maintaining life functions, however,there are still unsolved questions about its mechanisms. It is of great practical significance to study these issues for medical chip design, drug development, health care, etc. In this investigation, the conductivity properties of λ-DNA solutions with mono-/divalent metal ions(Na+, K^(+), Mg^(2+), and Ca^(2+)) are experimentally studied as they are electrically driven through a 5 μm microfluidic channel. Experimental data indicate that the conductivities of λ-DNA solutions with metal ions(M+/M2+) basically tend to reduce firstly and then increase as the voltage increases, of which the turning points varied with the metal ions. When the voltage surpasses turning points, the conductivity of λ-DNA-M+solutions increases with the concentration of metal ions, while that of λ-DNA-M^(2+)solutions decrease. Moreover, the conductivity of λ-DNA-M^(2+)solutions is always smaller than that of λ-DNA-M+solutions, and with high-concentration M^(2+), it is even smaller than that of the λ-DNA solution. The main reasons for the above findings could be attributed to the polarization of electrodes and different mechanisms of interactions between metal ions and λ-DNA molecules. This investigation is helpful for the precise manipulation of single DNA molecules in micro-/nanofluidic space and the design of new biomedical micro-/nanofluidic sensors.

Removal of ions from produced water using Powder River Basin coal

In addition to being used as an energy source,coal also has significant potential for other,more sustainable uses including water treatment.In this study,we present a simple approach to treat water that was produced during oil production and contained a total dissolved solids(TDS)content of over 150 g/L using Powder River Basin(PRB)coal.PRB coal used as packing material in a flow-through column effectively removed 60%–80%of the cations and anions simultaneously.Additionally,71%–92%of the total organic carbon in the produced water was removed as was all of the total suspended solids.The removal mechanisms of both cations and anions were investigated.Cations were removed by ion exchange with protons from oxygen-containing functional groups such as carboxylic and phenolic hydroxyl groups.Anions,mainly Cl−1,appeared to be removed through either the formation of resonance structures as a result of delocalization of electrons within coal molecules or through ion–πinteractions.We propose that coal is a“pseudo-amphoteric”exchange material that can remove cations and anions simultaneously by exchanging ions with both ionized and non-ionized acids that are ubiquitous in coal structure or resonance effect.

Influence of amphotericin B on liquid crystal state of the Cholesterol/Dipalmitoylphosphatidylcholine monolayer in the presence of different metal cations

Amphotericin B is a very effective antifungal drug,but it has an adverse reaction to the membrane of mammals＇ cells.The interaction between Am B and cholesterol（Chol） causes the formation of pores on the membrane to destroy its integrity.In particular,Am B has a significant effect on the permeability of membrane for K~＋ions.It has been reported that Na＋ions and Ca^（2＋）ions may have some influence on the interaction between amphotericin B and lipid molecules.In this work,the effects of these metal cations on the physical state and intermolecular interaction of the Cholesterol/Dipalmitoylphosphatidylcholine（Chol/DPPC） monolayer with and without Am B have been investigated.The addition of Am B induces the change of physical state of the lipid monolayer from liquid-gel phase to liquid phase.Different metal cations could influence the phase transition of the Am B-lipid monolayer.The K~＋ions and Ca2＋ions make the obvious phase transition disappear.However,the presence of Na＋ions has little influence on the phase transition of the Am B-lipid monolayer.The addition of Am B and the presence of different metal cations weaken the attractive force on the monolayers.After addition of Am B,the force between the molecules is the strongest in the environment of K＋ions,thus is the weakest in the environment of Ca^（2＋）ions,which may be due to the distribution of these metal cations inside and outside of cells.A large number of K＋ions distribute inside of the cells,thus most of Na＋and Ca^（2＋）ions exist out of the cells.Hence,it may be possible that when Am B molecules are out of the cells,the reaction between the drug and lipid molecules is weaker than that inside the cells.These results may have a great reference value for further studying the toxicity mechanism of Am B and the influence of metal cations on the membrane.

Corrigendum to “Peptide backbone-copper ring structure: A molecular insight into copper-induced amyloid toxicity”

The author list originally given in Wang et al. Chin. Phys. B 31 108702 (2022) has been amended to remove four authors, Hua Li, Bin Wu, Jun Guo and Chenqi Xu, who believe their contributions are more suitable to be credited in the acknowledgments.

Anionic entanglement-induced giant thermopower in ionic thermoelectric material Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K

Ionic thermoelectric(i-TE)technologies can power Internet of Things(IoT)sensors by harvesting thermal energy from the environment because of their large thermopowers.Present research focuses mostly on using the interactions between ions and matrices to enhance i-TE performance,but i-TE materials can benefit from utilizing different methods to control ion transport.Here,we introduced a new strategy that employs an ion entanglement effect.A giant thermopower of 28 mV K^(-1)was obtained in a quasi-solid-state i-TE Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K gel via entanglement between CF_(3)SO_(3)^(-)and CH_(3)SO_(3)^(-)anions.The anionic entanglement effect involves complex interactions between these two anions,slowing anionic thermodiffusion and thus suppressing bipolar effects and boosting p-type thermopower.A Au@Cu|Gelatin-CF_(3)SO_(3)K–CH_(3)SO_(3)K|Au@Cu i-TE device with a generator mode delivers a specific output energy density of 67.2 mJ m^(-2)K^(-2)during 2 h of discharging.Long-term operation.

New Insights into the Ion-Specific Behaviors and Design Strategies for Ion–πInteractions

Ion–πinteractions play a critical role in many important biological processes,such as gene expression,nicotine addiction,ion channel function,and so on,through recognizing specific ions by the receptors.However,widely used models,such as electrostatic potential and quadrupole moment,either treat ions as point charges or consider arenes only such that the key role of the information carried by ions is rarely discussed.Here,we shed light on the ion specificities in ion–πinteractions by correlating binding energies to a new model,namely the orbital electrostatic energy(OEE),which describes the electrostatic properties of both ions and theπsystems in detail via electron density distributions on orbitals.With this more detailed descriptor of electrostatics,new insights behind several important experimental and theoretical behaviors of ion–πinteractions are revealed,which will provide a deeper understanding of molecular recognition and communication through ion–πinteractions.On top of the OEE model,an ion-specific design strategy is proposed.

Peptide backbone-copper ring structure:A molecular insight into copper-induced amyloid toxicity

Copper ions can promote amyloid diseases that are associated with amyloid peptides, such as type 2 diabetes(T2D),Alzheimer's disease(AD), Parkinson's disease(PD), and amyotrophic lateral sclerosis(ALS). However, the underlying molecular mechanism remains obscure. Here we present that Cu^(2+)is able to specifically bind to the backbone of T2D related human islet amyloid polypeptide(hIAPP) by forming a ring structure, which causes the reduction of Cu^(2+)to Cu^(+) to produce reactive oxygen species(ROS) and the modulation of hIAPP aggregation. Nuclear magnetic resonance spectroscopy showed that Cu^(2+)bound to the backbone of a turn region, His18-Ser21, which is critical for hIAPP aggregation.Ab initio calculations and x-ray absorption fine structure analyses revealed that Cu^(2+)simultaneously bound with both the amide nitrogen and carbonyl oxygen on the peptide backbone, resulting in a ring structure, and causing the reduction of Cu^(2+)to Cu^(+) to form a hIAPP-Cu^(+) complex. 2′,7′-dichlorodihydrofluorescin diacetate fluorescence measurements further indicated that this complex led to enhanced ROS levels in rat insulinoma cells. Additionally, thioflavin T fluorescence and atomic force microscopy measurements denoted that the backbone-Cu ring structure largely modulated hIAPP aggregation,including the inhibition of hIAPP fibrillation and the promotion of peptide oligomerization. These findings shed new light on the molecular mechanism of Cu^(2+)-induced amyloid toxicity involving both the enhancement of ROS and the modulation of hIAPP aggregation.

Insight on metal ions inducing chiral self-assembly of DNA in silica mineralization

The self-assembly of DNA provides an attractive approach to understanding structural formation mechanism in living organisms and to assisting applications in materials chemistry.Herein,we investigated the effect of metal ions on chiral self-assembly of DNA through the synthesis of chiral mesostructured silica via self-assembly of metal ions,DNA,and silica source.31 types of multivalent cationic metal ions were found to induce formation of chiral impeller-like DNA-silica complexes due to the chiral stacking of DNA.The strength of the interaction between the metal ion and phosphate group of DNA was speculated for the chiral stacking of DNA due to close distance of adjacent DNA to assure mutual recognition.Theoretical calculations indicated that chiral packing of DNA depends on the stability of the bridging phosphate-metal ion-phosphate bonds of DNA based on electron delocalization in d-orbital conjugation of metal ions.

Low-energy ion channeling in nanocubes

Focused ion beam(FIB)processing with low-energy ions has become a standard technique for the manipulation of nanostructures.Many underlying ion beam effects that deviate from conventional high-energy ion irradiation of bulk systems are considered today;however,ion channeling with its consequence of significant deeper penetration depth has been only theoretically investigated in this regime.We present here an experimental approach to determine the channeling of low-energy ions in crystalline nanoparticles by measuring the sputter yield derived from scanning electron microscopy(SEM)images taken after irradiation under various incident ion angles.Channeling maps of 30 and 20 keV Ga+ions in Ag nanocubes have been identified and fit well with the theory.Indeed,channeling has a significant impact on the transport of energetic ions in crystals due to the large critical angle at low ion energies,thus being relevant for any FIB-application.Consequently,the obtained sputter yield clearly differs from amorphous materials;therefore,it is recommended not to rely only on,e.g.,ion distribution depths predicted by standard Monte-Carlo(MC)algorithms for amorphous materials.

Removal of ammonium ion from water by Na-rich birnessite:Performance and mechanisms

Na-rich birnessite（NRB） was synthesized by a simple synthesis method and used as a high-efficiency adsorbent for the removal of ammonium ion（NH＋4） from aqueous solution.In order to demonstrate the adsorption performance of the synthesized material,the effects of contact time,pH,initial ammonium ion concentration,and temperature were investigated.Adsorption kinetics showed that the adsorption behavior followed the pseudo second-order kinetic model.The equilibrium adsorption data were fitted to Langmuir and Freundlich adsorption models and the model parameters were evaluated.The monolayer adsorption capacity of the adsorbent,as obtained from the Langmuir isotherm,was 22.61 mg NH＋4-N/g at283 K.Thermodynamic analyses showed that the adsorption was spontaneous and that it was also a physisorption process.Our data revealed that the higher NH＋4adsorption capacity could be primarily attributed to the water absorption process and electrostatic interaction.Particularly,the high surface hydroxyl-content of NRB enables strong interactions with ammonium ion.The results obtained in this study illustrate that the NRB is expected to be an effective and economically viable adsorbent for ammonium ion removal from aqueous system.

Crystal-field analyses for trivalent lanthanide ions in LiYF_4

Based on the completely parametric crystal-field model, the energy level parameters, including free-ion parameters and crystal-field parameters, obtained by fitting the experimental energy level data sets of Ln^（3＋） in LiYF_4 were systematically analyzed. The results revealed that the regular variation trends of the major parameters at relatively low site symmetry still existed. The g factors of ground states were calculated using the parameters obtained from least-squares fitting. The results for Ce^（3＋）, Nd^（3＋）, Sm^（3＋）, Dy^（3＋） and Yb^（3＋） were in good agreement with experiment, while those of Er^（3＋） deviated from experiment dramatically. Further study showed that the g factors depended strongly on B_4~6, and a slightly different B_4~6 value of -580cm^（-1） led to g factors agreeing well with the experimental values.