Charge Variation Research Articles

Characterization of Silicone Rubber/MgO Nanocomposites for Grippers in Transmission Line Inspection Robots

The effect of addition of nanoparticles to silicone rubber is studied in this paper in the context of soft robotic applications to transmission line maintenance. Silicone rubber and polylactic acid (PLA) are used in the fabrication of these robotic structures. Desirable characteristics for the materials making the structure are (i) Low surface charge and space charge accumulation and (ii) High tensile and tear strength. To meet these requirements, addition of nano MgO to silicone rubber is proposed and studies pertaining to surface potential variation, space charge variation and dielectric parameters are performed. It is observed that 3wt% MgO added silicone rubber shows better performance than pure silicone rubber. Further, silicone rubber/MgO nanocomposite sandwiched PLA shows least space charge at the electrodes and at the interfaces of the sandwich. Moreover, the mechanical properties are also enhanced via the addition of nano MgO. In particular, 3wt% MgO added silicone rubber shows maximum tensile and tear strength. A direct correlation between tear strength and Shore A hardness is also observed. In addition, substantial improvement in viscoelastic properties of silicone rubber is observed with the addition of nano MgO.

Synthesis and Characterization of Copper Nanoparticles: Investigating Antibacterial Potential via Size and Surface Charge Modulations

This research delves into a comprehensive investigation of copper nanoparticle synthesis and characterization, with a specific emphasis on exploring their antibacterial potential by manipulating size and surface charge. Employing a customized approach, precise control over nanoparticle dimensions and surface properties was achieved. Variations in size were attained by fine-tuning reaction parameters, while surface charge modifications were implemented through ligand functionalization. Thorough characterization using diverse analytical techniques, such as transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential measurements, and Fourier-transform infrared spectroscopy (FT-IR), was conducted to elucidate morphological aspects and surface features. This multifaceted characterization aimed to provide a comprehensive understanding of the synthesized copper nanoparticles. Antibacterial assessments against various bacterial strains, spanning Gram-positive and Gram-negative species, were carried out, and the results were meticulously correlated with variations in nanoparticle size and surface charge. The outcomes not only advance the knowledge of copper nanoparticle synthesis but also shed light on the intricate relationship between nanoparticle properties and their antibacterial efficacy. This research holds promise for the development of tailored antibacterial agents with specific physicochemical properties, offering potential applications in antimicrobial materials and biomedical interventions, contributing to the evolving landscape of nanotechnology-driven solutions for combating bacterial infections.

Is it possible to ”simply” predict the photoejection of a cation? Example of azacrown-substituted [(bpy)Re(CO)[formula omitted]L][formula omitted] complexes

In the context of designing efficient photocontrolled ion-release systems, we propose a ”simple” computational strategy able to predict the cation photoejection. Our strategy is based on TD-DFT calculations and the analysis of the charge transfer (CT) parameters of the excited states that can be populated for a given excitation wavelength, in the Franck–Condon region.With the help of CT descriptors (the variation of the electronic density, the so-called DCT index and the variation of natural population analysis NPA charges), we aim to identify the CT states presenting a depletion of electronic density on the complexation site after excitation. If the loss of electronic density is large enough in the cation binding site, the population of such a state should be the first step of the mechanism leading to the cation photorelease.We test this strategy on ReAZBAP+-Mn+ (Mn+ = Li+, Na+, Mg2+, Ca2＋, Ba2+) and ReAZAT+-Ba2+ systems, a series of complexes synthesized and studied by Moore and co-workers [Lewis et al. (2004)]. We show that our first-order approach that does not take into account the complex excited-state decay routes, is able to correctly predict the photorelease properties with a success rate of ca. 80 percent. This method should thus be considered as a valuable tool in the framework of the in silico design of light-controlled ion release.

Dynamical second-order noise sweetspots in resonantly driven spin qubits

Quantum dot-based quantum computation employs extensively the exchange interaction between nearby electronic spins in order to manipulate and couple different qubits. The exchange interaction, however, couples the qubit states to charge noise, which reduces the fidelity of the quantum gates that employ it. The effect of charge noise can be mitigated by working at noise sweetspots in which the sensitivity to charge variations is reduced. In this work we study the response to charge noise of a double quantum dot based qubit in the presence of ac gates, with arbitrary driving amplitudes, applied either to the dot levels or to the tunneling barrier. Tuning with an ac driving allows to manipulate the sign and strength of the exchange interaction as well as its coupling to environmental electric noise. Moreover, we show the possibility of inducing a second-order sweetspot in the resonant spin-triplet qubit in which the dephasing time is significantly increased.

Dye adsorption properties of poly(p-phenylene terephthalamide)-embedded hollow fiber composite membranes

Hollow fiber composite (HFC) membrane with improved dye adsorption properties was prepared by the embedding of poly(p-phenylene terephthalamide) (PPTA)/polysulphone (PSF) microparticles into the polyamide (PA) composite layer of PSF hollow fiber membrane. As the polymer raw material of Aramid-1414, high modulus and hydrophilic PPTA was polycondensated in situ in PSF system and PPTA/PSF microparticles were obtained by the cloud-point precipitation method. PSF hollow fiber membrane was fabricated by the dry-jet wet-spinning technique. The variations of membrane morphology, porosity, surface charge and hydrophilicity were evaluated by the scanning electron microscope (SEM) observation, dry-wet mass difference, Zeta potential and water contact angle (WCA) measurements. The adsorption thermodynamic and kinetic processes of different kinds of dyes including anionic dye (Congo red, CR) and cationic dye (methylene blue, MB) were thoroughly investigated by three typical typical sorption isotherm models and two classical kinetic models, respectively. Compared with the PSF hollow fiber membrane and the pristine HFC membrane, the surface roughness, hydrophilicity and electronegativity had an obvious enhancement. The PPTA-embedded HFC membrane presented an increased dye adsorption capacity. The adsorption isotherms for CR and MB of the PPTA-embedded HFC membrane could fit well with the Langmuir and Sips models. The adsorption kinetics for CR and MB are in good agreement with the pseudo-first-order model and pseudo-second-order model, respectively. The prepared PPTA-embedded hollow fiber composite membranes are expected to be a promising candidate for the treatment of textile dyeing wastewater.

The shock wave solutions of modified ZK Burgers equation in inhomogeneous dusty plasmas

Abstract This paper offers a shock wave solution to modified Zakharov–Kuznetsov (MZK) Burgers equation in inhomogeneous dusty plasmas with external magnetic field. For this purpose, the fluid equations are reduced to an MZK Burgers equation containing variable coefficients by reductive perturbation method. With the aid of travelling-wave transformation technique, we obtain the analytical oscillatory shock wave solution and monotonic shock wave solution for MZK Burgers equation. The effects of inhomogeneity, external magnetic field, dust charge variation on characteristics of two types of shock waves are examined in detail.

Red Wine Oxidation Characterization by Accelerated Ageing Tests and Cyclic Voltammetry.

In order to obtain information on the oxidative behavior of red wines, oxygen consumption rates and electrochemical changes (cyclic voltammetry) were measured for nine red wines subject to three different accelerated ageing tests: chemical (with hydrogen peroxide), enzymatic (with laccase from Trametes versicolor), and temperature (at 60 °C). Oxidative behavior depended both on the wine sample and accelerated ageing test type. A good correlation was observed between electrochemical parameters of charges for reference/non-oxidized wines, in accordance with their antioxidant capacity, and the variation of charges after enzymatic and temperature tests, meaning that cyclic voltammetry could be used in order to predict these two oxidation tests and reflect the wine sensitivity towards respective oxidation targets. However, it was not possible to predict wine chemical oxidation test based on hydrogen peroxide from the electrochemical measurements.

Fabrication of protein-coated titanium dioxide nanoparticles for cellular uptake fluorescence imaging and treatment of colorectal cancer

Titanium dioxide (TiO2) coated with different proteins has exhibited exceptional bio-compatibility, leading to various biomedical engineering applications. With the use of green and chemical reduction methods, we fabricated Titanium dioxide nanoparticles that were protein-coated. Bovine serum albumin (BSA), lysozyme proteins, zein, and collagen have been used to coat titanium dioxide-aryl nanoparticles of the form TiO2-NPs. However, in both cases, no catalysts or other stabilizing agents were used. These images of TiO2-NPs fabricated using the green method show high crystallinity. It is a malignant colorectal tumour with dysfunctional cellular processes that cause colorectal cancer cells. It is hoped that studies employing SW1417 cells would give mechanistic ideas on the specifics of the amplification in cancers. This was done by flow cytometry utilizing and laser confocal fluorescence microscopy (LCFM) on the SW1417 colorectal cell line. Of the protein-coated Titanium dioxide nanoparticles fabricated green methods, BSA@TiO2-NPs were the most readily absorbed. Of all TiO2-NPs, lysozyme@TiO2-NPs fabricated by the chemical reduction technique were the most effectively internalized by SW1417 cells out of TiO2-NPs types. However, TiO2-NPs fabricated by the green methodology were coated with zein and lysozyme and tiny. A hydrophobic covering is also on the two nanoparticles. There is a possibility that the variation in hydrophobicity and charge affected the internalization process. Colorectal diagnostic and therapeutic compounds might be synthesized from those coated nanoparticles that were effectively internalized.

Cells electric charge analyses define specific properties for cancer cells activity

The surface electrical charge of cells is conditioned by the ionic medium in which they are immersed. This charge is specific for each cell type and is especially important in tumour cells because it determines their state of aggregation and their adhesion in the different organs. This study analyses the variations in surface charge of cells when pH, electrolytes, and their concentration are modified. The modification of these factors leads to changes in the surface charge of tumour cells; therefore, their states of aggregation and behaviour can be modified. This may even have a use in the prognosis and treatment of various tumours. Some studies conclude that the activity associated with the glycolysis process is accompanied by a change in the surface charge of cells. Notably, there is a high rate of glycolysis in tumours. Our results show that surface charge of cells strongly depends on nature of ionic medium in which they are found, with the valence of the majority ion being the most important factor. When ionic strength was high, the charge decreased dramatically. On the other hand, charge becomes zero or positive in an acidic pH, while in a basic pH, the negative charge increases.

Controlled assembly of heterogeneous aggregates of clay, iron hydr(oxydes) and polysaccharide: Effects of preparation conditions

The preparation of well-defined organo-mineral assemblies under controlled conditions is required to improve our understanding of the formation and surface reactivity of micrometric aggregates, ubiquitous in soils and continental aquatic media. We aim at investigating the building of organo-mineral assemblies with a specific focus on the assembly mode and its consequence on the final properties of the micrometric aggregates. In this work, the preparation and detailed characterization of clay-size aggregates composed of a clay mineral (illite), organic polymer (Dextran polysaccharide) and iron (hydr)oxide are reported, with a focus on the structural organization of the generated aggregates. A step-by-step strategy was developed, and three sets of clay-size composites were prepared with illite particles as a starting material. In two first steps, two distinct sets of two-component composites were obtained according to different procedures. Illite‑iron (hydr)oxide composites were obtained by alkaline hydrolysis of iron in the presence of illite particles, and illite-Dextran aggregates were obtained through the addition of Dextran polysaccharide to an illite suspension. In a third step, three-component micro-aggregates were obtained by subsequent addition of Dextran to suspensions containing the formed illite‑iron (hydr)oxide composite. The so-prepared 2- and 3- component aggregates were investigated by electrophoresis, electron microscopy, X-ray absorption and FTIR spectroscopies. For materials containing Dextran, electrophoretic mobility measurements evidenced variations of surface charge, combined with an increase of aggregate size highlighted by dynamic light scattering. Electron microscopy and EXAFS at iron K-edge evidenced the precipitation of nanoparticles of iron (hydr)oxide onto clay mineral surfaces. FTIR data in transmission and diffuse reflectance modes supported not only the adsorption of Dextran but also the preferential localization of Dextran at the external surfaces of the aggregates. All in all, data collected on the two- and three-component materials demonstrated that the presence of iron (hydr)oxide nanoparticles on the surface of illite strongly modified the organization of organic and mineral constituents.

Size and roughness dependent temperature effects on surface charge of silica nanoparticles

Silica nanoparticles (SNP) with different sizes and surface areas are used in numerous micro/nanofluidic applications, while their surface charge properties play a major role in their function. In many of these applications, SNPs also undergo temperature variation. We present that an increase in temperature yields a substantial increase in SNP surface charge depending on nanoparticle size and surface roughness, which cannot be estimated by existing theory. As a continuation of our earlier work characterizing the deviation of SNP surface charging from theoretical predictions due to curvature and EDL overlap effects, this study presents the differentiation from the theory in temperature dependence under various conditions. As we calculate surface chemistry as a function of local ionic conditions (Charge Regulation), temperature variation changed the equilibrium constants of protonation/deprotonation reactions of the SNP surface, in addition to changes occurring in relative permittivity and ionic mobilities. Results show that variation of SNP surface charge by temperature decreases by decreasing particle size and/or increasing roughness size, compare to theoretical flat plate calculations considering similar temperature-dependent properties and charge regulation on the surface. We characterized these deviations by obtaining an “electrokinetic similarity” between different systems of various size and roughness at various ionic conditions based on the non-dimensional groups of λ/D P and λ/D R . Based on these, we devised a phenomenological model as an extension to the flat plate theory to successfully predict the surface charge of SNPs as a function of the particle size, roughness size, and temperature. The current findings are important for the characterization of SNPs through temperature variations and can also be used to adjust the surface charge of SNPs by tuning the temperature. • Nanoparticle surface charge increases with increasing temperature. • Temperature effects on surface charge change with particle size and surface condition. • Temperature dependent ionic diffusion and surface charge regulation were considered. • Temperature dependent solution of PNP with charge regulation is presented. • A model for nanoparticle charging is extended from analytical solution.

Holographic entanglement entropy and modular Hamiltonian in warped CFT in the framework of GMMG model

We study some aspects of a class of non-AdS holography where the 3D bulk gravity is given by generalized minimal massive gravity (GMMG). We consider the spacelike warped AdS_3 (WAdS_3) black hole solution of this model where the 2d dual boundary theory is the warped conformal field theory (WFCT). The charge algebra of the isometries in the bulk and the charge algebra of the vacuum symmetries at the boundary are compatible and this is an evidence for the duality conjecture. Further evidence for this duality is the equality of entanglement entropy and modular Hamiltonian on both sides of the duality. So we consider the modular Hamiltonian for the single interval at the boundary in associated to the modular flow generators of the vacuum. We calculate the gravitational charge in associated to the asymptotic Killing vectors that preserve the metric boundary conditions. Assuming the first law of the entanglement entropy to be true, we introduce the matching conditions between the variables in two side of the duality and we find equality of the modular Hamiltonian variations and the gravitational charge variations in two sides of the duality. According to the results of the present paper we can say with more sure that the dual theory of the warped AdS3 black hole solution of GMMG is a Warped CFT.

Atomic configurations and energies of Mg symmetric tilt grain boundaries: ab initio local analysis

Mg alloys are highly expected for the wide application in the next-generation industry, while significant improvement of the plasticity of polycrystalline Mg alloys is crucial. For this purpose, it is essential to get insights into the atomic configurations, energetics, and mechanical responses of Mg grain boundaries (GBs). In this study, we investigated the overall features of atomic configurations and energies of and symmetric tilt GBs in hcp Mg by density-functional theory. We systematically constructed atomic models of coincidence-site lattice GBs by the arrangement of structural units in the full range of rotation angles. We observed that special GBs show clear cusps in both the GB-energy and excess-volume curves against the rotation angle. The reason of the stability/instability of each GB configuration was analyzed by ab initio local energy and local stress based on Bader partitioning. The features of local energies and stresses in Mg GBs are quite different from those in other materials with covalent or partial-covalent bonding nature. We observed substantial variations of local energies, local stresses and Bader charges of GB atoms, and charge inhomogeneity in a GB region, reflecting the structural disorder. Stable GBs are characterized by modest ranges of such variations and by moderate charge homogeneity. These results could be utilized in general to understand the interface stability and deformation mechanism of Mg and other simple metals.

Computational design of passivants for CdTe grain boundaries

CdTe is the second most-widely deployed photovoltaic (PV) material due to its high efficiency and low manufacturing costs. Currently, polycrystalline CdTe (poly-CdTe) has a record efficiency of ~22%, which is still well below the theoretical limit (~30%). Polycrystalline CdTe films that have incorporated Cl or Se show higher efficiency, possibly due to the segregation of these ions to the grain boundaries (GBs), where they may passivate the dangling bonds. However, the efficiency enhancement mechanisms of passivants in CdTe GBs, and the feasibility of employing alternative passivants, have not been well explored. Here, we present a systematic computational study of CdTe GBs with potential passivants, namely S, P, As, Se, and Sb on Te sites, and Na, Mg, Al, Sc, Cu, and Zn on Cd sites. Density functional theory (DFT) calculations were performed on GB dislocation core structures derived from scanning transmission electron microscopy (STEM) images of a model GB (bicrystal). We computed the segregation thermodynamics, electronic density of states, and charge variations near doped CdTe GBs. We find that segregation of impurities to GBs is thermodynamically favorable. For a Te-terminated core, Se, S, and P on Te sites effectively reduce midgap states. For both Cd- and Te- terminated dislocation cores, Sc and Al reduce midgap states when substituted for Cd atoms. The greatest improvement was achieved with co-doping, i.e. simultaneously substituting Te with Se and substituting Cd with Cu or Al. The elimination of midgap states is predicted to increase the photovoltaic efficiency of CdTe by reducing the recombination at grain boundaries. • CdTe solar cell efficiency depends highly on grain boundary properties. • Large scale first principles computational study was performed on realistic grain boundary models. • For a Te-terminated core, Se, S, P, and As on Te sites effectively reduce midgap states and improve efficiency. • For both Cd- and Te- terminated dislocation cores, Sc and Al on Cd sites reduce the midgap states and improve efficiency.

EMPIRICAL STUDY OF HOSPITAL CHARGE ON PSYCHOSES IN US

ABSTRACT In US, quite a portion of people suffer from psychosis and hospital charges on psychosis treatment have been consistently high. The hospital charge varies widely with so many factors, we categorize these factors into three groups (graphic, clinical, institutional and interaction), run a linear regression using data (DRG=885) and examine variations of hospital charge and contribution of different groups of variables to the variation. Our findings help patients, policy makers, hospital administrators understand more about groups of variables and their contribution to increase of hospital charges. Keywords Hospital charge, demographic variable, clinical variable, institutional variable, interaction, psychosis.

Intrinsic Origin of Nonhysteretic Oxygen Capacity in Conventional Na-Excess Layered Oxides

An intriguing redox chemistry via oxygen has emerged to achieve high-energy-density cathodes and has been intensively studied for practical use of anion-utilization oxides in A-ion batteries (A: Li or Na). However, in general, the oxygen redox disappears in the subsequent discharge with a large voltage hysteresis after the first charge process for A-excess layered oxides exhibiting anion redox. Unlike these hysteretic oxygen redox cathodes, the two Na-excess oxide models Na2IrO3 and Na2RuO3 unambiguously exhibit nonhysteretic oxygen capacities during the first cycle, with honeycomb-ordered superstructures. In this regard, the reaction mechanism in the two cathode models is elucidated to determine the origin of nonhysteretic oxygen capacities using first-principles calculations. First, the vacancy formation energies show that the thermodynamic instability in Na2IrO3 increases at a lower rate than that in Na2RuO3 upon charging. Second, considering that the strains of Ir-O and Ru-O bonding lengths are softened after the single-cation redox of Ru4+/Ru5+ and Ir4+/Ir5+, the contribution in the oxygen redox from x = 0.5 to 0.75 is larger in Na1-xRu0.5O1.5 than that in Na1-xIr0.5O1.5. Third, the charge variations indicate a dominant cation redox activity via Ir(5d)-O(2p) for x above 0.5 in Na1-xIr0.5O1.5. Its redox participation occurred with the oxygen redox, opposite to the behavior in Na1-xRu0.5O1.5. These three considerations imply that the chemical weakness of Ir(5d)-O(2p) leads to a more redox-active environment of Ir ions and reduces the oxygen redox activity, which triggers the nonhysteretic oxygen capacity during (de)intercalation. This provides a comprehensive guideline for design of reversible oxygen redox capacities in oxide cathodes for advanced A-ion batteries.

Low‐frequency variable charge solitary waves in a collisionless dusty plasma with a Cairns‐Gurevich ion velocity distribution

AbstractIn this paper, the problem of large amplitude dust acoustic (DA) solitons has been addressed in a charge varying dusty plasma with ions following a Cairns‐Gurevich distribution. Based on the orbit motion limited approach, the correct Cairns‐Gurevich ion charging current is presented for the first time. The expression relating the variable dust charge to the plasma potential is given in terms of the Lambert function and we take advantage of this transcendental function to, carefully, analyse DA solitons in a charge varying dusty plasma with trapped nonthermal ions. Our results show that the spatial patterns of the variable charge solitary wave are significantly changed due to the presence of ion population modelled by the Cairns‐Gurevich distribution. An addition of a small concentration of trapped nonthermal ions makes the solitary structure less spiky, grows the net negative charge residing on the dust grain surface, and contributes to the electron depletion. Finally, our investigation is extended to highlight the effect of the grain dust charge variation. We have shown that under certain conditions, the impact of dust charge fluctuation may furnish an alternate physical mechanism rasing anomalous dissipation, which becomes more strong and may predominate over the dispersion as the nonthermal character of ions following the Cairns‐Gurevich distribution increases.

Experimental investigations of pressure stimulated currents from stressed sandstone used as precursors to rock fracture

Precursor information of rock fracture is a prerequisite for rock dynamic disaster (RDD) prediction. To investigate the precursor information of rock fracture based on pressure stimulated current (PSC), progressive loading (PL) and step-like loading (SLL) experiments on sandstone samples were conducted. The response characteristics of PSCs from sandstone samples being actively loaded in the laboratory were analyzed and potential precursors to rock fracture based on PSCs are discussed. The results show that weak currents are generated instantaneously when a load is applied on sandstone samples and the PSCs correspond well to stress variations. In the PL experiments, the PSC responses are different in the different stages of deformation. In the compaction stage, the PSC first increases linearly and rapidly as the stress becomes greater but then decreases slowly a few seconds later; In the elastic stage, the current increases slowly and linearly with stress but it begins to rise with an increasing rate when the sample enters the plastic deformation stage, reaching the peak value of PSC the instant the final fracture occurs. In the SLL experiments, when stress is increased from a lower to a higher stress step, the PSCs increase rapidly and reach peak values the moment the stress stops increasing. In addition, the peak current increases exponentially with stress rate with a negative exponent. During stress maintenance, the PSCs decay slowly before finally reaching a stable value, and the PSC decaying process obeys the non-extensive statistical mechanics . The accumulated charge increases linearly with the relative stress, but the charge increasing rate are different in the three deformation stages. The variation rate of accumulated charge in plastic deformation stage is approximately eleven times as that in elastic deformation stage. The variation of current has a precursor response to rock fracture: the increase of PSC with an accelerative rate can be used as a precursor of rock failure during a progressive loading, the increasingly intensive abrupt drops during the PSCs decay are precursors for rock fracture during creep, and the rapid increase of accumulated charge variation rate can be used as a precursor of rock fracture both under progressive and step-like loadings. These research results are expected to provide new ideas and methods for RDD prediction.

Cubosomal lipid nanoassemblies with pH-sensitive shells created by biopolymer complexes: A synchrotron SAXS study

We report a strategy for sustainable development of pH-responsive cubic liquid crystalline nanoparticles (cubosomes), in which the structure-defining lyotropic nonlamellar lipid and the eventually encapsulated guest molecules can be protected by pH-sensitive polyelectrolyte shells with mucoadhesive properties. Bulk non-lamellar phases as well as pH-responsive polyelectrolyte-modified nanocarriers were formed by spontaneous assembly of the nonlamellar lipid monoolein and two biopolymers tailored in nanocomplexes with pH-dependent net charge. The mesophase particles involved positively charged N-arginine-modified chitosan (CHarg) and negatively charged alginate (ALG) chains assembled at different biopolymer concentrations and charge ratios into a series of pH-responsive complexes. The roles of Pluronic F127 as a dispersing agent and a stabilizer of the nanoscale dispersions were examined. Synchrotron small-angle X-ray scattering (SAXS) investigations were performed at several N-arginine-modified chitosan/alginate ratios (CHarg/ALG with 10, 15 and 20 wt% ALG relative to CHarg) and varying pH values mimicking the pH conditions of the gastrointestinal route. The structural parameters characterizing the inner cubic liquid crystalline organizations of the nanocarriers were determined as well as the particle sizes and stability on storage. The surface charge variations, influencing the measured zeta-potentials, evidenced the inclusion of the CHarg/ALG biopolymer complexes into the lipid nanoassemblies. The polyelectrolyte shells rendered the hybrid cubosome nanocarriers pH-sensitive and influenced the swelling of their lipid-phase core as revealed by the acquired SAXS patterns. The pH-responsiveness and the mucoadhesive features of the cubosomal lipid/polyelectrolyte nanocomplexes may be of interest for in vivo drug delivery applications.

Modulation effect in adjacent dual metal single atom catalysts for electrochemical nitrogen reduction reaction

Nitrogen reduction reaction (NRR) is a clean mode of energy conversion and the development of highly efficient NRR electrocatalysts under ambient conditions for industrial application is still a big challenge. Metal-nitrogen-carbon (M-N-C) has emerged as a class of single atom catalyst due to the unique geometric structure, high catalytic activity, and clear selectivity. Herein, we designed a series of dual metal single atom catalysts containing adjacent M-N-C dual active centers (MN4/M'N4-C) as NRR electrocatalysts to uncover the structure-activity relationship. By evaluating structural stability, catalytic activity, and selectivity using density functional theory (DFT) calculations, 5 catalysts, such as CrN4/M'N4-C (M’ = Cr, Mn, Fe, Cu and Zn), were determined to exhibit the best NRR catalytic performance with the limiting potential ranging from −0.64 V to −0.62 V. The CrN4 center acted as the main catalytic site and the adjacent M'N4 center could enhance the NRR catalytic activity by modulation effect based on the analysis of the electronic properties including the charge density difference, partial density of states (PDOS), and Bader charge variation. This study offers useful insights on understanding the structure-activity relationship of dual metal single atom catalysts for electrochemical NRR.