Traditional metallic glasses (MGs), based on one or two principal elements, are notoriously known for their lack of tensile ductility at room temperature. Here, we developed a multiprincipal element MG (MPEMG), which exhibits a gigapascal yield strength, significant strain hardening that almost doubles its yield strength, and 2% uniform tensile ductility at room temperature. These remarkable properties stem from the heterogeneous amorphous structure of our MPEMG, which is composed of atoms with significant size mismatch but similar atomic fractions. In sharp contrast to traditional MGs, shear banding in our glass triggers local elemental segregation and subsequent ordering, which transforms shear softening to hardening, hence resulting in shear-band self-halting and extensive plastic flows. Our findings reveal a promising pathway to design stronger, more ductile glasses that can be applied in a wide range of technological fields.

The fast dynamic properties of the surface of metallic glasses (MGs) play a critical role in determining their potential applications. However, due to the significant difference in thermal history between atomic simulation models and laboratory-made samples, the atomic-scale behaviors of the fast surface dynamics of MGs in experiments remain uncertain. Herein, we prepared model MG films with notable variations in thermal stability using a recently developed efficient annealing protocol, and investigated their atomic-scale dynamics systematically. We found that the dynamics of surface atoms remain invariant, whereas the difference in dynamical heterogeneity between surface and interior regions increases with the improvement of thermal stability. This can be associated with the more pronounced correlation between atomic activation energy spectra and depth from the surface in samples with higher thermal stability. In addition, dynamic anisotropy appears for surface atoms, and their transverse dynamics are faster than normal components, which can also be interpreted by activation energy spectra. Our results reveal the presence of strong liquid-like atomic dynamics confined to the surface of laboratory-made MGs, illuminating the underlying mechanisms for surface engineering design, such as cold joining by ultrasonic vibrations and superlattice growth.

Constructing accurate interatomic potential and overcoming the exponential growth of structural equilibration time are challenges to the atomistic investigations of the composition-dependent structure and dynamics during the vitrification process of deeply supercooled multi-component metallic liquids. In this work, we describe a state-of-the-art strategy to address these challenges simultaneously. In the case of the representative Zr-Cu-Al system, in combination with a general algorithm for generating the neural-network potentials (NNP) of multi-component metallic glasses effectively and accurately, we propose a highly efficient atom-swapping hybrid Monte Carlo (SHMC) algorithm for accelerating the thermodynamic equilibration of deeply supercooled liquids. Extensive calculations demonstrate that the newly developed NNP faithfully reproduces the phase stabilities and structural characteristics obtained from the ab initio calculations and experiments. In the combined NNP-SHMC algorithm, the structure equilibration time in the deeply supercooled temperatures is accelerated by at least five orders of magnitudes, and the quenched glassy samples exhibit comparable stability to those prepared in the laboratory. Our results pave the way for the next-generation studies of the vitrification process and, thereby the composition-dependent glass-forming ability and physical properties of multi-component metallic glasses.

Understanding the growth and coarsening mechanisms of metal-organic framework (MOF) nanoparticles is crucially important for the design and fabrication of MOF materials with diverse functionalities and controllable stability. Oriented attachment (OA) growth is a common manner of MOF nanocrystal coarsening and agglomeration, but the underlying molecular mechanisms have not been well understood to date. Here we report the molecular-scale characterization of the OA interfaces of zeolitic imidazolate framework (ZIF) crystals by state-of-the-art low-dose aberration-corrected transmission electron microscopy. A series of OA interfaces with different molecular structures are captured, implying that multiple kinetic steps are involved in the OA growth of ZIF crystals from non-directional physical attractions between primary nanocrystals, lattice-aligned attachment of the ligand-capped nanocrystals, to coherent interfaces with perfect lattice alignment or stacking faults. It was found that the surface-capping organic ligands not only play an essential role in crystal lattice alignment by near-field directional interactions, but also dominate the interfacial reaction kinetics by interfacial diffusion-controlled elimination of excess surface-capping ligands. These observations provide molecular-scale insights into the OA growth mechanisms of ZIF crystals, which is important for engineering MOF crystal growth pathways by designing surface-capping ligands.

Soft magnetic composites (SMCs) consisting of insulated metallic magnetic particles are critical materials in modern electronics. However, the simultaneous optimization of power loss and permeability for SMCs remains challenging due to the vulnerable insulation layer inside. Here, we succeed in fabricating FeSiAl SMC by confined solid-state reaction between TiO2 and FeSiAl matrix, which leads to the formation of homogeneous and lattice-matched Al2O3 layer and brings about effective electrical insulation of FeSiAl particles. TiO2 can progressively release O atoms and confine the solid-state reaction strictly within the interfacial region. Meanwhile, itself becomes ferromagnetic with deficient oxygen, resulting in alleviated magnetic dilution. Fast domain wall displacement and small hysteresis loss are directly observed by in-situ Lorenz transmission electron microscopy. The obtained FeSiAl SMC exhibits low power loss of 130 mW center dot cm(-3) (50 mT, 100 kHz) and high effective permeability of 143, which is desired in energy-saving and high-efficiency devices. This work relates the interfacial behavior with magnetic properties and highlights a new strategy for fabricating high-performance SMCs.

Antibacterial elements and non‐contact heating abilities have been proven effective for antibacterial and antibiofilm activities, but it remains a challenge to integrate both within one material. Herein, assisted by the high‐entropy effect, FeNiTiCrMnCu x high‐entropy alloy nanoparticles (HEA‐NPs) with excellent photothermal heating properties for boosting antibacterial and antibiofilm performances are synthesized. Benefitting from the synergetic effect of copper ions released and thermal damage by the HEA‐NPs, more reactive oxygen species (ROS) are generated, leading to the rupture of the cell membranes and the eradication of the biofilms. As a result, the antibiofilm efficiency (400 µg mL −1 ) of the mostly optimized FeNiTiCrMnCu 1.0 HEA‐NPs in the marine nutrient medium, which is the worst‐case scenario for the antimicrobial material, can be improved from 81% to 97.4% under 30 min solar irradiation (1 sun). The present study demonstrates a new strategy for effectively treating marine microorganisms that cause biofouling and microbial corrosion using HEA‐NPs with photothermal heating characteristics as an antibacterial auxiliary.

(Sm,Y)Fe12-Based Magnets In article number 2203503, Xuefeng Zhang, Wei Li, and co-workers demonstrate the construction of a core–shell structure (Sm-rich shell and Y-rich core) in a (Sm,Y)Fe12-based magnet via a spontaneous spinodal decomposition process, resulting in the synchronous enhancement of magnetic properties and phase stability in the optimized alloy. An innovative strategy is thus provided, which has important significance for the design of high-performance magnets.

ThMn12 -type SmFe12 -based permanent magnets have exhibited great potential in advanced magnet motors because of their high temperature stability of magnetic properties. However, the applications could be seriously limited due to the trade-off between phase stability and intrinsic magnetic properties. In this work, an effective solution is demonstrated by constructing the core-shell structure (Sm-rich shell and Y-rich core) via a spontaneous spinodal decomposition process. The anisotropy field for the (Sm0.75 Y0.25 )(Fe0.8 Co0.2 )11.25 Ti0.75 alloy is mostly optimized to be 9.24 T at room temperature. Such an enhancement is ascribed to the pinning process of domain walls by the magnetic-hardening Sm-rich shell, which is directly observed by in situ Lorentz transmission electron microscopy and reconstructed by micromagnetic simulation. Moreover, the phase stability and saturation magnetization are simultaneously increased, which is attributed to the synergistic effect of Y, Co, and Ti substitutions. More importantly, the high μ0 Ms value of 1.52 T is comparable to the reported (Sm,Zr)Fe12 -based bulk alloys that contain a larger amount of soft α-Fe phases, indicating that this strategy is more promising toward bulk magnets. The present study provides a significant concept for the development of advanced permanent magnets and also has implications for understanding the structural origin of intrinsic magnetic configurations.

An atomistic understanding of annealing embrittlement is a longstanding issue for metallic glasses, which is still lacking due to the insurmountable gap between the thermal history of atomic models and laboratory-made samples. Here, based on a thermal-cycling annealing method that can vary the effective quenching rate over ten orders of magnitude, we perform an atomistic study of the ductile-brittle transition in a ternary model metallic glass, which can be keyed to the annealing embrittlement in bulk metallic glasses. We reveal that thermal annealing can effectively obliterate thermally active-able "defects", which are abundant in the hyper-quenched and ductile glass but gives rise to strain-created shear events in the well-annealed and brittle glass. While the activation of the strain-created events eventually causes single shear banding, other local structural disruptions can be "healed" by the same type of events upon stress reversal, thereby hindering shear band broadening or multiplication, and resulting in annealing embrittlement.

The properties of zeolitic imidazolate framework (ZIF) crystals highly depend on the structures of the low-energy surfaces, such as {110} of ZIF-8. However, the atomic/molecular configurations of the ZIF-8 {110} surfaces remain debated. In this study, the near-atomic-scale characterization of {110} surfaces of ZIF-8 is conducted by low-dose aberration-corrected transmission electron microscopy (TEM). The real-space images with mitigated surface delocalization by minimized spherical aberration of TEM, together with the solvent corrected surface energy calculations, demonstrate that the {110} surfaces of ZIF-8 crystals with an equilibrium-form rhombic morphology have a zigzag-type termination. This study provides experimental evidence to clarify the debated structure of {110} ZIF-8 surfaces and has important implications in understanding the crystal growth and surface related properties of ZIF-8.

Increasing the dielectric loss capacity plays an important role in enhancing the electromagnetic absorption performance of materials. It remains a challenge to simultaneously introduce multiple types of dielectric losses in the material. In this work, we show that the atomic and interfacial dipole polarizations can be simultaneously enhanced by substituting N species into both carbon coating layers and bulk TiC lattices of a core-shell TiC@C material. Additionally, substitution of N species results more exposed TiC(111) facets and refines the TiC grain sizes in the bulk material, which is beneficial for enhancing the scattering of the external electromagnetic waves. The maximum reflection loss of the N substituted TiC@C material is measured as-47.1 dB with an effective absorbing bandwidth of 4.83 GHz at 1.9 mm, which illustrates a valuable way to further tuning the electro-magnetic absorption performance of this type of materials.

High-performance electromagnetic wave absorption materials constitute key components of microelectronic devices. Traditional absorbents possess magnetic losses and/or dielectric losses, while the experimental approach for their simultaneous enhancement is still lacking. Here, we demonstrate that the core/shell structural Ni@C nanocapsules, functionalized by atomic-scale oxygen substitutions that can be formed catalytically by highly defective graphitic structure, present enhanced dielectric loss capacities at gigahertz. In particular, >90% of the microwave energy could be attenuated for a planar absorber with a thickness down to 1–1.5 mm at 7.6–13.8 GHz. Experimental characterizations coupled with density functional theory calculations further evidence that the capacity enhancement is ascribed to the structure breaking at the heterogeneous substitutional zones, resulting in the intrinsic polarization of carbon–oxygen heterostructures. The present study shows a new mentality of designing for optimizing electromagnetic wave absorption materials and also has pointed out the atomic-scale structural origin of the electromagnetic response performance.

The mechanism of different exposed crystal surfaces on dielectric polarization characteristics is of great significance to understand the interface impedance matching. In this work, the controllable preparation of titanium carbide (TiC) with different exposed crystal surface was realized by adjusting the reaction atmosphere, which is based on the growth rate and surface energy of different exposed facets. TiC(100)/graphite and TiC(111)/graphite interfaces are found in the truncated octahedral TiC/C nancomposites, while only TiC(100)/graphite interface exits in the cubic nanocomposites. Experimental conclusion companied by theoretical calculations identify that dielectric loss capacity is improved by the strong localization of polarized charge at TiC(111)/graphite interface. Due to the enhanced permittivity, dielectric loss ability and absorption coefficient, the truncated octahedral TiC@C nanocomposites exhibit the reflection loss of - 45.1 dB and the effective frequency bandwidth of 5.3 GHz at 2.1 mm. The proposed interfacial modulation strategy can provide a reference for designing high efficiency microwave absorber.

Electrochemical catalysis provides a clean and economical way for hydrogen peroxide synthesis. In this work, two-electron oxygen reduction activity on the functionalized graphene is studied via density functional theory calculation. We show that the theoretical catalytic activity can be controlled by structure and chemical functionalization of special carbon sites on the graphene. Especially, we show that partial sulfurized graphene nanoribbon shows catalytic activity close to the theoretical maximum and the excellent catalytic activity is explained by the doping level of C-2p state of the adsorption site.

Ga2O3, as an emerging optoelectronic material, is very appealing for the detection of ionizing radiation because of its low cost, wide band gap (4.5-5.0 eV) and radiation hardness. In this work, a flexible X-ray detector using amorphous Ga2O3 (a-Ga2O3) thin film is demonstrated. The a-Ga2O3 thin film was deposited on polyethylene naphthalate (PEN) substrate with delicately control of the oxygen flux during the radio frequency (RF) magnetron sputtering process. Metal/semiconductor/metal-structured photodetectors with coplanar interdigital electrodes were fabricated on this a-Ga2O3 film. Temporal response measurements under X-ray illumination indicate that a larger photocurrent occurs on the film deposited with smaller oxygen flux. A model combined with theoretical calculation is proposed to explain the enhancement of the X-ray photoresponsivity, which involves the slowing down of the annihilation rate caused by the neutralization of more ionized oxygen vacancy (V-0) states. No significant degradation of the device performance under UV and X-ray radiation is observed after the flexibility test. This finding informs a novel way to design the flexible X-ray and other ionizing radiation detectors based on amorphous oxide materials.

Understanding the carbon formation mechanism is critical for designing catalysts in various applications. Here, we report the observation of the carbon formation mechanism on Ni-based catalysts by environmental transmission electron microscopy (ETEM) over a wide temperature range in combination with molecular dynamics simulations and density functional theory calculations. In situ TEM observation performed in a C2H2/H2 atmosphere provides real-time evidence that Ni3C is an intermediate phase that decomposes to graphitic carbon and metallic Ni, leading to carbon formation. Mechanisms of acetylene decomposition and evolution of carbon atom configuration are revealed by molecular dynamics simulations, which corroborate the experimental results. The modification of MgO on NiO can effectively decrease the formation of graphitic layers and thus enhance the catalytic performance of NiO. This finding may provide an insight into the origin of the carbon deposition and aid in developing effective approaches to mitigate it.

Rational design of efficient and durable bifunctional catalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is important for rechargeable zinc-air batteries. Herein, Mg doped perovskite LaNiO3 (LNO) nanofibers (LNMO NFs) were prepared by a facile electrospinning method combined with subsequent calcination. LNMO NFs show a more positive half-wave potential of 0.69 V and a lower overpotential of 0.45 V at a current density of 10 mA cm(-2) than those of the pristine LNO NFs. As an air electrode for zinc-air battery, the cell with LaNi0.85Mg0.15O3 NFs catalyst is able to deliver a high specific capacity of 809.9 mAh g(-1) at a current density of 5 mA cm(-2). It also shows an excellent cycling stability over 110 h at a current density of 10 mA cm(-2). DFT calculation results demonstrate that the LNMO surface binds oxygen stronger than LNO, which contributes to enhanced OER activity as observed in our experiments. The results indicate that LNMO NFs are an efficient and durable bifunctional catalyst for zinc-air batteries.

AbstractPhase transition from WO3 to sub‐stoichiometric WO2.9 by a facile method has varied the typical semiconductor to be quasi‐metallic with a narrowed band gap and a shifted Femi energy to the conduction band, while maintaining a high crystallinity. The resultant WO2.9 nanorods possess a high total absorption capacity (ca. 90.6 %) over the whole solar spectrum as well as significant photothermal conversion capability, affording a conversion efficiency as high as around 86.9 % and a water evaporation efficiency of about 81 % upon solar light irradiation. Meanwhile, the promising potential of the nanorods for anticancer photothermal therapy have been also demonstrated, with a high photothermal conversion efficiency (ca. 44.9 %) upon single wavelength near‐infrared irradiation and a high tumor inhibition rate (ca. 98.5 %). This study may have opened up a feasible route to produce high‐performance photothermal materials from well‐developed oxides.

Rational design of efficient bifunctional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are critical for rechargeable Li-O-2 batteries. Here, we report inverse spinel Co[Co,Fe]O-4/nitrogen-doped graphene (NG) composite used as a promising catalyst for rechargeable Li-O-2 batteries. The cells with Co[Co,Fe]O-4/NG catalyst exhibit high initial capacity, remarkable cyclability, and good rate capability. Moreover, the overpotential of the Li-O-2 batteries is reduced significantly. The improved ORR/OER performances are attributed to the good property of Co[Co,Fe]O-4 with an inverse spinel structure toward ORR and the improved electronic conductivity of N-doped graphene. The density functional theory (DFT) calculation shows the rate limitation step for ORR on the inverse spinel surface is the growth of the Li2O2 cluster while the rate limitation step for the OER pathway is the oxidation of Li2O2. The inverse spinel surface in Co[Co,Fe]O-4/NG is more active than that of the normal spinel phases for the Li-O-2 battery reactions. This work not only provides a promising bifunctional catalyst for practical metal air batteries but also offers a general strategy to rationally design catalysts for various applications.