The electrochemical reduction of CO2 to CH4 offers a promising pathway for closing the carbon cycle and enabling sustainable energy conversion, yet it is fundamentally limited by sluggish reaction kinetics and competing side reactions. We report the controlled fabrication of core-shell Cu@Zn nanocluster catalysts (Cu@Zn NCs) via cluster beam deposition (CBD). Molecular dynamics simulations based on the NEP89 universal neuro- evolution potential reveal a spontaneous formation mechanism of the core-shell architecture. Aberration- corrected high-angle annular dark-field scanning transmission electron microscopy (AC-HAADF-STEM) further confirms uniform quasi-spherical Cu@Zn NCs with an average size of ~5.86 nm, a well-crystallized Cu (111) core, and a continuous Zn shell. In electrocatalytic CO2 reduction, the Cu@Zn NCs achieve a CH4 Faradaic efficiency of up to 63.1% with a partial current density of 126.2 mA cm2 at 1.5 V vs. RHE and a total current density of 200 mA cm2. Mechanistic investigations combining in situ infrared spectroscopy and hydrogen/ deuterium (H/D) kinetic isotope effects (KIE) analysis reveal that the Zn shell accelerates interfacial water dissociation, providing an abundant local proton source, while simultaneously strengthening *CO adsorption on Cu sites and promoting its hydrogenation to the key *CHO intermediate. This synergistic effect suppresses *CO desorption and C–C coupling pathways, thereby steering the reaction toward highly selective CH4 formation. This work highlights the effectiveness of precise interfacial engineering in bimetallic core-shell catalysts and provides mechanistic insights for the rational design of CH4 selective electrocatalysts for deep CO2 hydrogenation.

An entropy-stabilized multicomponent ultrahigh-temperature ceramic (UHTC) coating, (Ti0.25V0.25Zr0.25Hf0.25)B2, on a graphite substrate was in-situ sintered by spark plasma sintering (SPS) from constituent transition metal diboride powders. The (Ti0.25V0.25Zr0.25Hf0.25)B2 coating had a hardness of 31.2±2.1 GPa and resisted 36.9 GPa of stress before delamination, as observed at the interface. The temperature-dependent thermal properties of the multicomponent diboride (Ti0.25V0.25Zr0.25Hf0.25)B2 were obtained by molecular dynamics (MD) simulations driven by a machine learning force field (MLFF) trained on density functional theory (DFT) calculations. The thermal conductivity, density, heat capacity, and coefficient of thermal expansion obtained by the MD simulations were used in time-dependent thermal stress finite element model (FEM) simulations. The low thermal conductivity (< 6.52 W∙m−1∙K−1) of the multicomponent diboride coupled with its similar coefficient of thermal expansion to that of graphite indicated that stresses of less than 10 GPa were generated at the interface at high temperatures, and therefore, the coating was mechanically resistant to the thermal stress induced during ablation. Ablation experiments at 2200 °C showed that the multicomponent diboride coating was resistant to thermal stresses with no visible cracking or delamination. The ablation mechanisms were mechanical denudation and evaporation of B2O3 and light V–Ti oxides, which caused a decrease in the mass and thickness of the coating and resulted in mass and linear ablation rates of −0.51 mg·s−1 and −1.38 µm·s−1, respectively, after 60 s. These findings demonstrated the thermal and mechanical stability of multicomponent entropy-stabilized diborides as coatings for carbon materials in engineering components under extreme environments.

High-entropy materials have attracted considerable interest due to their unique, improved properties and large configurational entropy. Out of these, high-entropy ceramics (HECs) are of particular interest since the independent solubility of cations and anions results in increased configurational entropy. However, most HEC research considers only a single element occupying the anion sublattice, which limits the maximum attainable configurational entropy. Here, we expand our previous work on high-entropy borocarbides where both boron and carbon occupy the anion sublattice. By applying an ab initio based screening procedure, we identify six elements Li, Ti, V, Zr, Nb and Hf suitable for forming high-entropy borocarbides. With these elements, we propose six novel HEC compositions, and by computing their entropy forming ability, we identify that three are likely to form single-phase during synthesis. Material properties and lattice distortions for all proposed compositions are studied using density functional theory calculations with special quasirandom structures. The directional lattice distortions, a concept we introduce in this work, show that lattice distortions have an elemental and directional preference for certain HEC compositions. We also show that the novel inclusion of Li improves the mechanical properties of the proposed HECs, the details of which are studied using the electron localization function.

The inception of high-entropy alloy promises to push the boundaries for new alloy design with unprecedented properties. This work reports entropy stabilisation of an octonary refractory, HfMoNbTaTiVWZr, high-entropy thin film metallic glass, and derived nitride films. The thin film metallic glass exhibited exceptional ductility of ≈60% strain without fracture and compression strength of 3 GPa in micro-compression, due to the presence of high density and strength of bonds. The thin film metallic glass shows thermal stability up to 750 °C and resistance to Ar-ion irradiation. Nitriding during film deposition of HfMoNbTaTiVWZr thin film of strong nitride forming refractory elements results in deposition of nanocrystalline nitride films with compressive strength, hardness, and thermal stability of up to 10 GPa, 18.7 GPa, and 950 °C, respectively. The high amount of lattice distortion in the nitride films leads to its insulating behaviour with electrical conductivity as low as 200 S cm−1 in the as-deposited film. The design and exceptional properties of the thin film metallic glass and derived nitride films may open up new avenues of development of bulk metallic glasses and the application of refractory-based high entropy thin films in structural and functional applications.

The use of machine learning to accelerate computer simulations is on the rise. In atomistic simulations, the use of machine learning interatomic potentials (ML-IAPs) can significantly reduce computational costs while maintaining accuracy close to that of ab initio methods. To achieve this, ML-IAPs are trained on large datasets of images, which are atomistic configurations labeled with data from ab initio calculations. Focusing on carbon, we use deep learning to train neural network potentials (NNPs), a form of ML-IAP, based on the state-of-the-art end-to-end NNP architecture SchNet and investigate how the choice of training and validation data affects the performance of the NNPs. Training is performed on the CA-9 dataset, a 9-carbon allotrope dataset constructed using data obtained via ab initio molecular dynamics (AIMD). Our results show that image generation with AIMD causes a high degree of similarity between the generated images, which has a detrimental effect on the performance of the NNPs. But by carefully choosing which images from the dataset are included in the training and validation data, this effect can be mitigated. We conclude by benchmarking our trained NNPs in applications such as relaxation and phonon calculation, where we can reproduce ab initio results with high accuracy.

Polymers containing catechol groups have gained a large interest, as they mimic an essential feature of mussel adhesive proteins that allow strong binding to a large variety of surfaces under water. This feature has made this class of polymers interesting for surface modification purposes, as layer functionalities can be introduced by a simple adsorption process, where the catechol groups should provide a strong anchoring to the surface. In this work, we utilize an AFM-based method to evaluate the wear resistance of such polymer layers in water and compare it with that offered by electrostatically driven adsorption. We pay particular attention to two block copolymer systems where the anchoring group in one case is an uncharged catechol-containing block and in the other case a positively charged and catechol-containing block. The wear resistance is evaluated in terms of wear volume, and here, we compare with data for similar copolymers with statistical distribution of the catechol groups. Monitoring of nanomechanical properties provides an alternative way of illustrating the effect of wear, and we use modeling to show that the stiffness, as probed by an AFM tip, of the soft layer residing on a hard substrate increases as the thickness of the layer decreases. The stick–slip characteristics are also evaluated.

Transition metal borides have a unique combination of high melting point and high chemical stability and are suitable for high temperature applications (>2000 °C). A metastable dual-phase boride (Ti_0.25V_0.25Zr_0.25Hf_0.25)B₂ with distinct two hexagonal phases and with an intermediate entropy formation ability of 87.9 (eV/atom)⁻¹ as calculated via the density functional theory (DFT) was consolidated by pulsed current sintering. Thermal annealing of the sintered dual-phase boride at 1500 °C promoted the diffusion of metallic elements between the two boride phases leading to chemical homogenization and resulted in the stabilization of a single-phase high-entropy boride. Scanning electron microscopy, in situ high temperature x-ray diffraction, and simultaneous thermal analysis of the as-sintered and annealed high-entropy borides showed the homogenization of a dual-phase to a single-phase. The experimentally obtained single-phase structure was verified by DFT calculations using special quasirandom structures, which were further used for theoretical investigations of lattice distortions and mechanical properties. Experimentally measured mechanical properties of the single-phase boride showed improved mechanical properties with a hardness of 33.2 ± 2.1 GPa, an elastic modulus of 466.0 ± 5.9 GPa, and a fracture toughness of 4.1 ± 0.6 MPa m^1/2.

Recent breakthroughs in the field of single-walled carbon nanotube (SWCNT) growth have been achieved by combining theoretical models with experiments. Theoretical models rely on accurate energies for SWCNTs, obtained via first principle calculations in the form of density functional theory (DFT). Such calculations are accurate, but time and resource intensive which limits the size and number of systems that can be studied. Here, we present a new analytical model consisting of three fundamental energy expressions, parametrized using DFT, for fast and accurate calculation of SWCNT energies at any temperature. Tests against previously published results show our model having excellent accuracy, with an root mean square error in total energies below 2 meV per atom as compared to DFT. We apply the model to study SWCNT growth on Ni catalysts at elevated temperatures by investigating the SWCNT/catalyst interface energy. Results show that the most stable interface shifts towards chiral edges as the temperature increases. The model’s ability to perform calculations at any temperature in combination with its speed and flexibility will allow researcher to study more and larger systems, aiding future research into SWCNT growth

Harnessing energy lost in the form of heat is an important challenge today. Organic thermoelectric materials (TE) can convert lost heat into electricity at relatively low temperature. Single-walled carbon nanotubes (SWCNTs) are known to boost the TE properties of organic-based materials at room temperature (TR). However, the TE performance decreases with the increasing temperature, which restricts the working temperature region of the devices. Here, we present a three steps investigation: initially, the influence of the net of SWCNTs on TE properties of polymer matrix; secondly, creation of hybrid fillers via SWCNTs treatment with gold chloride; lastly, chemical post-treatment of obtained systems in the temperature range 325–410 K. In the process of HAuCl4 aerosolization (gold chloride treatment) on the surface of nanotubes, different ionic conformations (Au and AuCl4−) can be formed. For this reason, we performed a theoretical investigation on the influence of ionic conformations on SWCNTs on the electronic structure. Implementation of SWCNTs net into polymer matrix alongside gold chloride doping and chemical post-treatment successfully increased the power factor of the system in the temperature interval from 300 to 410 K. These results demonstrate the potential of combined approach in creation of hybrid fillers based on organic/inorganic materials with chemical post-treatment in boosting the thermoelectric performance within the whole operating temperature of polymer-based composite alongside the importance of theoretical modeling in tuning the electronic structure of composite systems through a material-by-design approach.

Development of high-entropy alloy (HEA) films is a promising and cost-effective way to incorporate these materials of superior properties in harsh environments. In this work, a refractory high-entropy alloy (RHEA) film of equimolar CuMoTaWV was deposited on silicon and 304 stainless-steel substrates using DC-magnetron sputtering. A sputtering target was developed by partial sintering of an equimolar powder mixture of Cu, Mo, Ta, W, and V using spark plasma sintering. The target was used to sputter a nanocrystalline RHEA film with a thickness of ∼900 nm and an average grain size of 18 nm. X-ray diffraction of the film revealed a body-centered cubic solid solution with preferred orientation in the (110) directional plane. The nanocrystalline nature of the RHEA film resulted in a hardness of 19 ± 2.3 GPa and an elastic modulus of 259 ± 19.2 GPa. A high compressive strength of 10 ± 0.8 GPa was obtained in nanopillar compression due to solid solution hardening and grain boundary strengthening. The adhesion between the RHEA film and 304 stainless-steel substrates was increased on annealing. For the wear test against the E52100 alloy steel (Grade 25, 700–880 HV) at 1 N load, the RHEA film showed an average coefficient of friction (COF) and wear rate of 0.25 (RT) and 1.5 (300 °C), and 6.4 × 10–6 mm3/N m (RT) and 2.5 × 10–5 mm3/N m (300 °C), respectively. The COF was found to be 2 times lower at RT and wear rate 102 times lower at RT and 300 °C than those of 304 stainless steel. This study may lead to the processing of high-entropy alloy films for large-scale industrial applications.