Reclamation of emulsified waste organic solvents through filtration adsorption using an under-liquid superlyophilic wood membrane.

ABSTRACT 1.1 nm tobermorite, a component of concrete, is considered to play a key role in its long-term durability and strength development. The microscopic mechanisms of monotonic compression and recompression loading in 1.1 nm tobermorite are investigated in this study using ab initio molecular dynamics simulations. Under monotonic compression, a clear stress-recovery phenomenon is observed. Simulations reveal that this behavior originates from the slipping of Si–O chains. This slip induces atomic rearrangement and subsequently leads to the formation of new Si–O bonds that bridge the Ca–O layers. In contrast, in the recompression case, the simulations show that the compression history significantly alters the atomic configuration before recompression. Because the Si–O bonds formed within the Ca–O layers are already preferentially aligned along the compression direction, the Si–O chains do not slip during recompression.

The development of machine learned interatomic potentials (MLIPs) is critical for performing reliable simulations of materials at length and time scales that are comparable to those in the laboratory. We present here a MLIP suitable for simulations of the temperature dependent structure and dynamics of single layer hexagonal boron nitride (h-BN) with defects and grain boundaries, developed using a strictly local equivariant deep neural network, Allegro. The training dataset consisted of ∼30 000 images of h-BN with and without point defects generated with abinitio molecular dynamics simulations, based on density functional theory (DFT), at 500, 1000, and 1500K. The developed MLIP predicts potential energies and forces with a mean absolute error of 4meV/atom and 60 meV/Å, respectively. It also reproduces phonon dispersion curves and density of vibrational states of pristine bulk h-BN that are comparable with those obtained from DFT calculations. Using this MLIP to study the motion of the 4|8 grain boundary in h-BN we show that the initial motion of the first unit has an activation barrier of ∼2.2eV. Moving the grain boundary units past the first shows much lower activation barriers of ∼0.42eV, suggesting a facile motion of the grain boundary once the initial movement is stimulated. Molecular dynamics simulations of the grain boundary yield a scaled mobility of 1.739 × 10-11m3/Js at 1500K which, given the different setups without continuous e-beam irradiation, is not too far from the experimental value of 1.36 × 10-9m3/Js. The ability to predict grain boundary mobility within reasonable agreement with experiment demonstrates the robustness of the MLIP and its suitability for reliable simulations of defect structures and dynamics in single layer h-BN.

Abstract Electrocatalytic oxygen reduction reaction in seawater represents a sustainable approach for hydrogen peroxide (H 2 O 2 ) production, yet industrial-level current densities trigger severe cathodic alkalization and scaling issues, while aggressive acidification of the reaction system compromises catalytic efficiency. Here we show a cationic modification strategy that dynamically modulates the acidic electrified interface to promote both the formation and desorption of the key *OOH intermediate for H 2 O 2 synthesis. Enabled by this strategy, the cationic-modified catalysts achieve >90% efficiency at 500 mA cm -2 in natural seawater, and even reach 1.125 A cm -2 in high-salinity electrolytes, with a competitive estimated cost of $0.64 per kilogram of H 2 O 2 . Ab initio molecular dynamics simulations reveal that the introduced cationic modifications effectively counteract O–O bond cleavage induced by both the inherent strong binding of catalytic sites and the potential-induced over-binding effect under highly negative potentials, and thus facilitate *OOH desorption for H 2 O 2 formation. This work highlights dynamic interfacial intermediate stabilization as a strategy that complements conventional static binding-energy tuning, enabling high-current-density H 2 O 2 electrosynthesis in seawater.

Brookite TiO2, a rare natural polymorph of TiO2, has been reported to be an excellent photocatalyst for the production of hydrogen from water and aqueous alcohol solutions, especially when it is reduced and synthesized in the form of nanorods. Here, we investigate the reactivity of stoichiometric and reduced brookite nanorods in liquid water using ab initio molecular dynamics and hybrid density functional theory calculations. Our simulations show a much higher water dissociation fraction on reduced nanorods than on stoichiometric ones, with an accumulation of the resulting bridging hydroxyls (ObrH) and terminal hydroxyls (Ti-OH) on different facets of the nanorod. ObrH groups accumulate preferentially on low-energy (210) facets, where they are stabilized by adjacent reduced Ti (Ti3+) sites, while Ti-OH groups prefer to form at the 4-fold coordinated Ti atoms on high-energy (010) facets. This hydroxylation pattern also favors the spatial localization of excited holes on the (010) facets. This coupling between water-induced surface chemistry and charge separation underpins the enhanced photocatalytic activity of brookite nanorods, providing useful information for the design of more efficient TiO2-based nanostructures for solar-driven hydrogen evolution.

Atomically precise Au25 nanoclusters are ideal catalyst models for unraveling the nanozyme structure-activity relationship due to their well-defined structures and tunable electronic properties. Herein, ab initio molecular dynamics (AIMD) simulations combined with density functional theory (DFT) calculations were employed to systematically investigate the ligand removal behavior and peroxidase (POD)-like catalytic activity of Au25 nanoclusters modified with phosphine (PR), thiol (SR), alkynyl (C≡CR), and N-heterocyclic carbene (NHC) ligands. Constrained AIMD (cAIMD) simulations revealed that all clusters preferentially remove halogen ligands (Cl/Br) with free energy barriers below 0.25 eV, while NHC and phosphine ligands exhibit stronger binding stability with the Au core. The exposed low-coordination gold sites upon halogen removal display excellent POD-like activity, wherein the second *OH reduction (or the second TMB oxidation) is determined to be the rate-determining step (RDS). Among them, [Au25(NHC)10(Br)6]2+-top (removal of Br at the top coordination site) exhibits the most optimal activity with a moderate RDS barrier (0.83 eV) owing to its isolated active site and higher d-band center that balance *OH adsorption and the catalytic activity. This study clarifies the structure-activity relationship of atomically precise Au25 nanoclusters in the peroxidase-like catalysis, providing a quantitative basis for high-efficiency Au-based nanozyme design.

Two-dimensional antimonene has recently emerged as a promising electrocatalytic platform; however, its oxygen reduction reaction (ORR) activity and modulation strategies remain largely unexplored. Herein, density functional theory (DFT) calculations are employed to systematically investigate ORR catalysis on antimonene co-doped with transition metal (TM) and nonmetal (C, P) dual atoms. The results reveal that Pd@C-Sb, Pt@C-Sb, and Pd@P-Sb exhibit remarkably enhanced ORR activity, delivering low overpotentials of 0.31 V, 0.32 V, and 0.38 V, respectively, significantly outperforming their single-atom-doped counterparts. Mechanistic analyses demonstrate that nonmetal dopants induce strong synergistic interactions with TM centers, leading to charge redistribution and effective regulation of the TM d-band center, which optimizes the adsorption energetics of key ORR intermediates. Notably, the number of d-electrons of TM atoms is identified as a reliable electronic descriptor governing intermediate binding strength and catalytic activity. Furthermore, ab initio molecular dynamics simulations confirm the excellent thermodynamic stability of the optimized dual-atom catalysts. This work elucidates the atomic-scale origin of synergistic enhancement in dual-atom-doped antimonene and provides a rational design strategy for high-performance ORR electrocatalysts based on two-dimensional main-group materials.

Precisely deciphering the intrinsic origin of the high overpotential for oxygen evolution reaction (OER), even on the most active RuO2 catalysts, remains a long-standing challenge in electrocatalysis. Herein, by meticulously elucidating the electrode charging behavior, oxygenated surface phases and interfacial double-layer structures under OER-relevant potentials on RuO2(110), together with their impact on reaction pathways and elementary-step energetics through ab-initio molecular dynamics simulations, we reveal that the high overpotential jointly arises from the pronounced surface negative charge, due to the unusually high potential of zero charge, and the excessive protonation of surface-active *O at coordinatively unsaturated Ru sites (*OCUS) at low potentials (<1.60V). This, on one hand, severely depletes active *OCUS intermediate, thereby suppressing the rate-determining step (RDS) of oxide pathway mechanism (OPM), necessarily involving surface O─O coupling between two *OCUS via Langmuir-Hinshelwood mechanism. On the other hand, it induces the dense, strongly hydrogen-bonded interfacial water layer that, together with electrostatic repulsion, obstructs the essential water reorientation and approach for the RDS of adsorbate evolution mechanism (AEM), featuring incoming interfacial water to reorient and react with *OCUS via Eley-Rideal-like mechanism. Furthermore, a potential-dependent mechanistic switching between AEM and OPM is identified, dictated by their distinct RDS natures and kinetic sensitivities.

Efficient carbon capture and utilization require strategies that minimize energy penalties of CO2 regeneration and compression. Reactive capture and conversion (RCC) address this challenge by integrating capture with direct electrochemical conversion. Here, we show an NH3-mediated tandem RCC system that couples capture of CO2 from simulated flue gas (10% v/v CO2 in N2) with electroreduction of NH4HCO3 to CO over a Ni single-atom catalyst (Ni-SAC). Speciation modeling and capture experiments revealed that a deep CO2 capture with C/N ratio of 0.65 was achieved using 2.5 M NH3 from simulated flue gas. Electrolysis of the resulting NH4HCO3 on the Ni-SAC delivered an 85% CO Faradaic efficiency at 100 mA/cm2 with excellent tolerance to NH3/NH4 + as confirmed by DFT calculations and ab initio molecular dynamics (AIMD) simulations. Further, the techno-economic analysis established a levelized total cost of CO manufacturing of $25.43/kmol, gauging the practical viability. Overall, this study holds great potential to decarbonize the chemical manufacturing industry while reducing synthetic production costs.

Two-dimensional (2D) van der Waals heterostructures (vdWHs) enable unprecedented flexibility in tailoring the structural and optoelectronic properties, facilitating their use across diverse next-generation device applications. Here, we used the first-principles study and comprehensively examined MoS2 and MXO (M = Mo, W; X = S, Se, Te) monolayers and their layered vdWHs. We modeled 12 different stacking configurations of MoS2-MXO vdWHs for model-I and model-II (six for each model) and examined their stability through binding energy, interlayer distance, and ab initio molecular dynamics (AIMD) simulations at room temperature. Remarkably, MoS2-MXO vdWHs exhibit a staggered type-II band alignment, while MoS2-WTeO vdWHs show type-I band alignment, confirming that they inherently facilitate spatial separation of photogenerated electrons and holes, showing good response toward high-efficiency optoelectronic and photocatalytic water splitting. Work function and plane-averaged electrostatic potential difference, as well as charge density difference distributions were investigated, which highlight pronounced charge redistribution and potential steps, underscoring the presence of interlayer charge transfer at the interface of MoS2-MXO vdWHs that can effectively modulate carrier dynamics. The optical response was explored through calculations of the complex dielectric function, revealing pronounced absorption across the visible and also near-infrared regions, confirming it as an appealing candidate for high-performance solar energy conversion, photodetection, and optoelectronics. Further, photocatalytic applications of MoS2-MXO vdWHs were examined by aligning their band edges with respect to the redox potentials of water for pH = 0-3. Our results demonstrated that the band edge positions of MoS2-MXO vdWHs possess the thermodynamic requirements necessary for visible-light-driven water splitting, hence enabling both hydrogen and oxygen evolution reactions. Collectively, our findings establish MoS2-MXO vdWHs as promising platforms for next-generation photocatalytic hydrogen production, offering a viable route toward sustainable and clean energy technology applications.

Hybrid metal halide perovskites consist of the organic cation (A-site) and inorganic skeleton (B-site metal cation and X-site halide anion). Traditionally, the electronic structures near the band edges are mainly controlled by the inorganic component, with the A-site having negligible influence as its electronic states lie far from the band edges. In this work, we show that by adjusting the configuration of organic cations and introducing substituents, the A-site can directly contribute to the band-edge electronic states. Using density functional theory calculations, ab initio molecular dynamics simulations, confocal spectroscopy, and synchrotron high-pressure diffraction, we uncover the origins of band-edge electronic state reconfiguration in 2D hybrid lead halide perovskites. Our results demonstrate that the conjugation of organic cations, combined with the electron-donating and withdrawing substituents, enables the reconfiguration of band-edge electronic states. Specifically, electron-donating groups raise the energy levels of the organic cation, allowing its contribution to the valence band maximum. Conversely, electron-withdrawing groups lower these levels, enabling participation at the conduction band minimum. This mechanism is confirmed by our use of tailored cations together with temperature- and pressure-dependent studies. This work offers a new approach for tailoring the electronic states of hybrid metal halide perovskites with desired optoelectronic performance.

The lead-rich liquid lithium-lead eutectic alloy, Li17Pb83, is one of the candidates to be used in breeding blanket modules of future fusion reactors where tritium breeding is essential to provide the necessary fuel for fusion. It has several properties that favour its use, such as the breeding capacity of Li, the neutron multiplication capacity of Pb, the ease of circulation for off-site tritium recovery, and the capability to, at least partly, refrigerate the system. It is therefore important to understand the properties of the tritium generated in the breeding reactions, and its effects on the hosting liquid. The same applies to helium nuclei that are generated in a 1:1 ratio to tritium in the breeding reactions. We have performed first principles molecular dynamics simulations to study the structural changes observed in liquid Li 17 Pb 83 when tritium or helium is added. In one set of simulations we have made calculations for several amounts of tritium, with molar concentrations ranging from 0.20 to 0.03, without any He atoms. In the other set of simulations we have included helium atoms with molar concentration 0.11, and no tritium. Tritium atoms are found to bind preferentially with Li, modifying substantially the Li-Li correlation functions. We also observe the presence of long-lasting di-tritium molecules when tritium concentration is not too low, which also tend to bind to Li atoms. The velocity autocorrelation functions of tritium, Li and Pb are evaluated, and analysed in order to obtain the corresponding vibrational properties of the different species. Helium atoms tend to aggregate together forming a cluster whose characteristics are reported, together with the correlation functions of He atoms with Li and Pb. The motion of He atoms within this cluster is found to be sub-diffusive, while an estimate of He mobility outside the aggregate is also given.

The BBHA (p-butoxybenzylidene p-heptylaniline) is a Schiff base produced via the condensation process of p-butoxybenzaldehyde and p-heptylaniline. It has a negative anisotropic dielectric constant, which improves display modes at lower working voltages. Substitution of an electronegative element improves the liquid crystal's nonlinear optical performance. BO 2 is a superhalogen with stronger electronegativity than other halogens. In this communication, all calculations of BBHA and its mono- and di-substituted superhalogen species, BO 2 , on the substituted H of the phenyl ring of BBHA were performed using a combination of DFT/B3LYP approach using a 6–311 + +G(d, p) basis set. The estimated L/B ratio dihedral angle ovality (O) of BBHA and BBHA(BO 2 ) n for n = 1–2 demonstrates that, while some considerable deformation occurs, the geometry of BBHA does not vary from rod shape following mono and di substitution of BO 2 on BBHA. The quadrupole moment (TQ) trace shows how electrooptical properties change upon mono- or di-substitution of BO 2 in BBHA. The optical activity (AQ) characteristics of BBHA and BBHA(BO 2 ) n (n = 1–2) rise monotonically as the superhalogen BO 2 is mono- and di-substituted into BBHA. The NBO analysis demonstrates that charge transfer from the phenyl ring to superhalogen BO 2 stabilizes BBHA(BO 2 ) n for n = 1–2, which improves BBHA's nonlinear optical behavior following di-substitution with superhalogen BO 2 . The electronic characteristics of BBHA, BBHA(BO 2 ) n for n = 1–2, are calculated using the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO), and density of states (DOS) plot. The energy gap between HOMO and LUMO indicates chemical reactivity, which decreases with mono and di substitution of superhalogen BO 2 on BBHA. The polarity emerges as a result of the substitution of superhalogen BO 2 , which requires less energy to convert an electron from HOMO to LUMO. The delocalization of charge throughout the entire molecule caused by the substitution of superhalogen BO 2 improves the hyperpolarizability of BBHA(BO 2 ) n for n = 2. The production of mono and di-substituted BBHA is thermodynamically advantageous in the forward direction. Pure BBHA, a well-known liquid crystal, is contrasted with the nonlinear optical behavior of mono and di-substituted superhalogen BO 2 on BBHA. The kinetic stability of mono- and di-substituted superhalogen BO 2 on the BBHA was studied using ab initio molecular dynamics simulations. In this approach, the current study demonstrates that mono- and di-substituted BBHA are unique liquid-crystalline molecules that can be used at ambient temperature.

Atomistic mechanisms of hydrogenation corrosion resistance in representative uranium nitrides via ab initio molecular dynamics simulations

Abstract This study theoretically evaluates the potential of nine types of M 2 C MXenes (M = Ti, V, Cr, Y, Nb, Mo, Ta, W, and Sc) as electrode materials for fluoride-ion batteries (FIBs). The investigation focuses on key performance metrics, including the fluoride-ion migration barrier, electronic structure, and thermal stability. Screening based on the minimum energy barriers for fluoride-ion migration on the material surfaces reveals a significant dependence of the kinetics on the transition metal M. Among the candidates, Mo 2 C exhibits the lowest fluoride-ion migration barrier, indicating superior rate capability. Further electronic structure analysis confirms the metallic character of Mo 2 C, ensuring good electronic conductivity. Ab initio molecular dynamics simulations demonstrate its excellent structural stability. These comprehensive theoretical findings highlight Mo 2 C as a highly promising electrode material for FIBs, providing a solid rationale and a specific target for subsequent experimental validation.

Ultrathin nanoporous membranes based on two-dimensional materials, including molybdenum disulfide (MoS2), offer excellent separation efficiency and chemical stability, making them promising candidates for water purification. Prior molecular dynamics (MD) simulations of MoS2 membranes assumed bare edge structures, neglecting functionalization arising from aqueous environments, due to the lack of suitable classical force fields. Here, we employ quantum-mechanical density functional theory (DFT) to conduct ab initio molecular dynamics simulations that elucidate the interfacial chemistry of MoS2 nanopores in water. Our results reveal a propensity for shape-dependent functionalization at molybdenum (Mo) and sulfur (S) edges of nanopores in MoS2. We observe a pronounced preference in hexagonal pores for hydrogenation (H) at S-terminated edges and oxo (O) functionalization at Mo sites. In contrast, triangular pores with Mo-exposed edges favor hydroxylation (OH), while S-terminated triangular pores remain inert, exhibiting no functionalization. These insights guide the development of accurate, transferable force fields for H-, O-, and OH-functionalized MoS2 nanopores, derived from DFT-computed potential energy surfaces. The resulting models enable stable, chemically realistic MD simulations of molecular and ion transport through MoS2 nanopores harboring various functional groups. Our findings highlight the significant role of edge chemistry in modulating nanoscale transport phenomena. We demonstrate that unfunctionalized S-terminated triangular pores, along with functionalized hexagonal pores, offer high water permeance while maintaining excellent salt and boron rejection, highlighting their potential as promising candidates for selective desalination membranes. Overall, this work offers a robust framework for modeling functionalized MoS2 nanopores in aqueous environments, advancing their application in separation, sensing, and nanofluidic technologies.

Controllable electrochemical construction of highly dual porous Co-Mn-S@Ni-Co heterojunction for boosting energy-saving hydrogen production assisted by urea oxidation reaction.

Unveiling the dynamic interface evolution co-induced by cations and vacancies for boosted in situ hydrogen peroxide electrosynthesis.

The vibrational energy relaxation dynamics of the excited free OH bond on the ice surface are investigated using abinitio molecular dynamics (AIMD) simulations. The present AIMD study reproduces experimental results obtained via pump-probe sum-frequency generation spectroscopy. Simulations were conducted at 100 and 200K for ice surfaces and compared with previous results at 300K for water surfaces. The relaxation mechanisms were analyzed by selectively constraining specific vibrational modes, revealing distinct pathways: intramolecular stretch coupling, bend coupling, and intermolecular stretch coupling via reorientation or dipole-dipole interactions. At higher temperatures, intramolecular stretch coupling dominates, while at lower temperatures, the reorientation of the free OH is restricted; alternatively, intermolecular dipole-dipole coupling becomes more significant due to the vibrational delocalization of ice. For isotopically diluted systems (HOD in D2O), relaxation occurs primarily through stretch-bend combination coupling.

Spin-polarized first-principles calculations were performed to investigate the physical properties of K₂NaXI₆ (X = Cr, Fe) halide double perovskites. Accurate electronic band gaps were obtained using the TB-mBJ exchange potential. Ab initio molecular dynamics simulations confirm the thermodynamic stability of both compounds. Electronic structure analysis reveals semiconducting behavior in both spin channels for K₂NaCrI₆ and K₂NaFeI₆. The calculated band gaps for K₂NaCrI₆ are 0.8eV in the spin-up channel and 1.8eV in the spin-down channel, whereas K₂NaFeI₆ exhibits band gaps of 3.2eV (spin-up) and 0.4eV (spin-down). Both materials display ferromagnetic ordering, with total magnetic moments of 3 µB for K₂NaCrI₆ and 5 µB for K₂NaFeI₆. Optical property calculations, including the real and imaginary parts of the dielectric function, indicate strong optical absorption spanning the visible to ultraviolet energy regions. Furthermore, thermoelectric analysis predicts n-type conduction behavior for K₂NaCrI₆ and p-type behavior for K₂NaFeI₆, highlighting their potential for multifunctional energy applications.