Proton exchange membranes (PEMs) are critical for tritium management in nuclear energy, enabling efficient separation and recovery of radioactive isotopes from contaminated wastewater. This study deciphers tritium-induced radiation damage by pioneering keV-level electron beam irradiation (57-200 keV) that accurately mimics beta-decay energy, combined with ReaxFF MD simulations and multiscale characterization. We reveal a hierarchical bond cleavage mechanism: Low-energy irradiation (57 keV) preferentially ruptures C-O-C/C-F bonds near -SO3H groups, while higher energies (>= 160 keV) progressively cleave C-S, S-O, and C-C bonds, forming carboxyl fragments and gaseous CO2/SO2. This hierarchy directly controls macroscopic degradation - tensile strength declines >65 % from side-chain fragmentation, proton conductivity drops >50 % due to disrupted ion channels, and fuel cell output plummets >79 % as fragments poison catalysts. Crucially, electron energy dominates damage pathways over absorbed dose, resolving discrepancies in prior MeV-beam studies. This work provides a mechanistic roadmap for designing radiation-resistant PEMs meeting ITER's 530-kGy requirement for tritiated water treatment.

In energy conversion semiconductor devices, radiation damage is directly related to the long-term stability of β-voltaic batteries. In this study, single-crystalline silicon P+NN+ devices and P+-silicon materials with SiO2 surface passivation were irradiated using a ~70 keV accelerator electron beam in a nitrogen atmosphere for 2 min, 10 min, 1 h, 6 h, and 12 h. The tritium-voltaic output decreased rapidly within the first 2 min of electron beam irradiation and then decayed slowly. After 1 h of irradiation, both the output short-circuit current (Isc) and open-circuit voltage (Voc) remained stable. The effects of the damage were analyzed using typical samples irradiated for 1 h. Neutron reflectometry (NR) was employed as the primary characterization method, while X-ray photoelectron spectroscopy (XPS)-combined with Ar+ etching-and secondary ion mass spectrometry (SIMS) were used to verify radiation-induced structural changes at the SiO2 surface and SiO2/Si interface. It was found that nitrogen atoms from the atmosphere penetrated the SiO2 layer to a depth of approximately 5-10 nm, forming a non-stoichiometric SiON structure, without further diffusion into deeper layers. Irradiation significantly increased the thickness of the SiO2/Si interface transition layer to about 14-18.5 nm, and the SiO2 structure within this layer became relatively loose. It can be inferred that tritium-voltaic batteries using SiO2-surface-passivated single-crystalline silicon P+NN+ devices as energy-conversion units and packaged in a nitrogen atmosphere can stably provide power for 10 years, with an Isc reduction of no more than 12% and a Voc reduction of no more than 6%, excluding the spontaneous decay of tritium.

Carbon materials possess attractive mechanical and thermal properties, yet creating bulk sp²-bonded carbon that unites high hardness, elastic recoverability, and thermal stability has remained elusive. Mechanical anisotropy, low damage tolerance, and structural instability under stress or at high temperatures hinder the development of dense sp²-carbon architectures for demanding environments. Here we report a dual-phase sp2 carbon produced from C60 at high pressure through progressive structural reconstruction, yielding a hierarchical structure in which stacked graphene nanoclusters are integrated within a disordered sp2-rich amorphous matrix. This architecture accommodates stress by structurally mediated interlayer sliding and elastic compaction, while retaining structural coherence. The resulting material achieves ~ 20 GPa hardness, > 88% elastic recovery, and oxidation resistance near 960 °C in air, representing an unusual combination of mechanical recoverability and thermal stability among representative carbon materials. Simulations show that the combination of stiffness and resilience arises from interfacial reinforcement between the ordered and disordered domains. This work identifies a structural pathway for engineering sp²-carbon systems that overcome long-standing limits in mechanical and thermal performance.

Thermoelectric technology enables direct heat-electricity conversion, with device reliability depending on the stability of interfaces between thermoelectric legs and metal electrodes. This study systematically investigates how Bi2Te3 substrate microstructure affects the thermal stability of Ni/Bi2Te3 interfaces. Four materials were selected: n-type zone-melted, n-type hot-extruded, p-type hot-pressed, and p-type hot-extruded. A Ni barrier layer was electroplated onto each substrate, followed by welding to a Cu electrode. Samples underwent heat treatments at different temperatures, and interfacial microstructure evolution, diffusion kinetics, and electrical performance degradation were analyzed. Results show that for both n-type and p-type materials, hot-extruded samples exhibit superior interfacial thermal stability. In n-type materials, interfacial reactions are dominated by grain-boundary diffusion. The refined grain structure and Bi/Se segregation at grain boundaries in hot-extruded n-type samples effectively suppress rapid Ni diffusion. In p-type materials, reactions are bulk-diffusion-controlled. For hot-extruded p-type samples, Bi enrichment near the interfacial reaction layer increases the kinetic barrier for Ni diffusion, significantly inhibiting reaction layer growth.

Performance and structural optimization of milliwatt-level radioisotope thermoelectric generators (RTGs) with end-mounted thermoelectric modules (TEMs) are investigated. A one-dimensional heat transfer model was developed to analyze temperature distribution and maximum output power (P-max) of the RTG. The sensitivity of P-max to TEM length (L) and cross-sectional area (A) was evaluated for RTGs using five thermoelectric materials. Results show that longer L and optimized A enhance the temperature difference (Delta T) and P-max. For a Bi2Te3-based RTG with single end TEM (RTG-1), optimal P-max reached 160.19 mW on Earth at L = 28 mm and A = 292.41 mm(2), and 273.17 mW on Titan at L = 28 mm and A = 161.29 mm(2). Dual-end TEM configurations (RTG-2) yielded identical power outputs. COMSOL simulations validated the model with >90% accuracy. Thermal contact resistance (R-C) analysis revealed higher R-C necessitates larger L/A ratios for optimal performance. The model provides a versatile tool for designing RTGs with diverse thermoelectric materials.

The active phase for methane combustion is still in debate. Low-temperature CO-FTIR spectroscopy was used to probe the working surface state on a series of Pd/Al2O3 (PdAl) and Pd/silicalite-1 (PdSil) catalysts with different starting states: oxidized, reduced (R), reoxidized (Ro). The surface of prereduced PdAl (Pd0) is transformed to an oxidized state (PdO x ) with a CO stretching vibration (nu CO) at similar to 2157 cm-1 when it is aged in the methane oxidation mixture. The aging-induced transformation from Pd0 to PdO x occurred at 250 degrees C or above. Although PdSil has multiple kinds of PdO x entities, prereduced PdSil also transformed into PdO x . For PdAl(4)-R-A250, XRD patterns suggest weak bulk oxidation of Pd0 at 250 degrees C, XPS spectra indicate 28% of surface Pd0 atoms are oxidized, but CO-FTIR spectra confirm all the "top surface" Pd0 atoms are oxidized. It demonstrates the advantage of CO-FTIR spectroscopy in probing the top surface state. Finally, a direct correlation between operando FTIR spectroscopy and low-temperature CO-FTIR spectroscopy was established. Operando FTIR spectra over PdSil during methane oxidation at 250 degrees C gives two bands at 2124 cm-1 (CO-Pd+) and 2161 cm-1 (CO-Pd2+). After cooling in nitrogen, CO-FTIR spectra give two similar bands at 2134 cm-1 and 2157 cm-1. The "working surface state" can be preserved in CO-FTIR. For PdAl(4), operando FTIR spectra at 250 and 300 degrees C give no bands of adsorbed CO. Adding CO into the methane oxidation mixture resulted in a single CO-Pd2+ band at 2163 cm-1, which is in accord with their CO-FTIR spectra. For operando FTIR spectroscopy, the observation of the bands of adsorbed CO depends on the accumulation of the CO intermediates, but their accumulation is limited to reaction temperatures below 300 degrees C and to PdSil (not PdAl). These limitations make low-temperature CO-FTIR spectroscopy more general and sensitive.

Metal tritides have long been applied in tritium storage due to their high capacity and stability. The decay of tritium produces helium-3 (He-3), which is mainly retained in metal tritides in the form of bubbles. Although the evolution of helium-3 bubbles in metal tritides has been of wide concern for a long time, the trend of their morphological transformation is still under debate. In this work, the shape evolution of helium bubbles in typical metal tritides (erbium, titanium, and zirconium) was tracked by transmission electron microscopy. The results show that in the tritides of erbium and titanium, helium-3 bubbles undergo a sphere-to-platelet transformation at the early stage (He-3/M = 0.02 similar to 0.06), while in zirconium tritide the helium-3 bubbles remain spherical up to He-3/M > 0.29. Compared with theoretical models, it is found that large and plate-like bubbles can maintain stability by widening rather than through a spherical transformation. Our results further suggest that the dominant energy contribution of helium-3 bubbles shifts from surface energy to strain energy with aging. Overall, the present work provides strong experimental support for investigating helium bubble behavior within metal tritide lattices, offering guidance for the rational design of tritium storage and fusion materials.

Development of a stable catalyst resistant to steam-induced sintering (10 vol%-15 vol% H2O, 450-550 degrees C) is challenging for catalytic combustion/oxidation of methane. We use the silicalite-1's internal defects to trap PdO clusters to construct a stable catalyst (PdO/silicalite-1). Silicalite-1 with sufficient amounts of silanol defects and ion exchange at alkaline condition are critical for this defect-trapping strategy. PdO/silicalite-1 shows long-term super-stability with respect to the temperatures and steam concentrations. The conversion remained stable over 200 hat 500 degrees C (10 vol% H2O) and declined slightly during 380 h at 550 degrees C (10 vol% H2O). PdO/silicalite-1's catalytic activity deteriorated slightly after hydrothermal aging at 750 degrees C or thermal aging at 850 degrees C. Electron microscopy reveals two growth modes for PdO clusters within silicalite-1 (PdOin) and on the external surface (PdOsurf). PdOsurf clusters agglomerate into PdO particles of 5-15 nm directly, but PdOin clusters first fuse into strip-shaped PdOin clusters, then migrate outwards and further agglomerate into PdO nanoparticles.

PEMFCs, crucial for space energy needs, rely on Nafion for proton conductivity and durability. High-energy radiation in space can degrade PEMFC performance. Therefore, in-depth research on the microstructural evolution of Nafion under high-energy radiation and its impact on PEMFC's performance is of great significance for promoting the application of fuel cell technology in the space field. This work combines experimental and computational simulation methods to propose the evolution mechanism of C-O-C rupture and -COOH generation in Nafion under high-energy radiation. The new molecular structure formed has increased chain spacing and free volume, enhanced water absorption and swelling properties, and decreased structural stability. When the radiation absorption dose exceeds 400 kGy, Nafion completely becomes brittle and cannot be used. The change in Nafion at 0-400 kGy structure resulted in a significant overall decrease in mechanical properties (decreased by 73.76 %), proton conductivity (decreased by 40.59 %), output power density (from 480.00 to 30.00 mW/cm2), hydrogen permeation (from 2.26 to 60.75 mA/cm2), and open-circuit voltage (from 1.01 to 0.27 V). This study not only enhances the understanding of Nafion's structural evolution and performance degradation under highenergy radiation but also provides important research directions for developing high-performance PEMFCs suitable for the space environment.

CdS/ZnS heterostructures with tunable band gaps are promising photocatalysts for solar- or visible-light-driven H2 production through water splitting. To predict how the bandgap changes with the heterostructure composition, density functional theory calculations with meta-GGA correction are performed. It is found that the band gaps of CdS and ZnS are reduced by up to 14.5% and 43.3% in the heterostructures, respectively. The content of CdS in heterostructures plays a vital role in tuning the band gap and conduction band edge level. With the increasing number of CdS layers, the band gap first decreases and reaches a minimum value for (CdS)5/(ZnS)5, and then increases slightly. As a result, the (CdS)m/(ZnS)n (m >= 3, m + n = 10, or >= 30% of CdS) heterostructures attain desirable band gaps in the range of 2.06-2.25 eV for visible light absorption and 0.305-0.444 eV more negative conduction band edge than the reduction potential of H+/H2 for water splitting. These results suggest that the composition of CdS/ZnS heterostructures can be adjusted to further improve the efficiency of photocatalysts for visible light absorption and water splitting/H2 production.

A series of body-centered cubic (BCC) multi-principal element alloys (MPEAs) with varying mean enthalpy of hydrogen solution (Delta H infinity), lattice parameter and atomic size mismatch (delta) were synthesized using the arc-melting method. The hydrogen storage properties of the MPEAs were investigated with differential scanning calorimetry (DSC) and manometric measurement in a Sieverts apparatus. Our results indicate that hydrogen storage capacities and the desorption activation energy (Ed) of the MPEAs decrease linearly as Delta H infinity increases. On the other hand, the desorption onset temperature increases linearly as Delta H infinity increases. These findings suggest that Delta H infinity is such an important parameter for designing MPEAs with predictable properties. Moreover, atomic size mismatch (delta) and lattice parameter are also two important parameters in predicting hydrogen storage properties, which suggests that predicting the properties of MPEAs is multidimensional.

A 3-D continuous electrorefiner is designed and investigated using multiphysics simulation for the separation of uranium and neptunium from spent nuclear fuel in molten salt. The concentration distribution field, the electric field, the ionic flux density field, and the flow field are evaluated under galvanostatic and pulse electrorefining by numerical integration of the governing equations using finite element method. During the electrorefining without molten salt recirculation, the transport of the electroactive cations is controlled by diffusion and electromigration and high concentration gradient is built near electrodes. In a galvanostatic electrorefining with a current density of 50 Am-2, the concentration of U3+ decreases to 26.7 molm-3 near cathode and increases to 62.5 molm-3 near anode within 40 s, and no co-deposition of uranium and neptunium occurs. In a galvanostatic electrorefining with a current density of 200 Am-2, the concentration of U3+ decreases to 1.3 molm-3 near cathode and increases to 62.6 molm-3 near anode within 6.7 s, and the co-deposition of uranium and neptunium occurs after 0.28 mg of pure uranium is collected. With moderate molten salt recirculation, the transport of the electroactive cations is controlled by convection. The local concentrations of uranium ions approach steady near the electrodes within 32 s in a galvanostatic electrorefining of 50 Am-2, and no co-deposition of uranium and neptunium occurs. Though the concentration of U3+ decreases to 21.1 molm-3 near cathode and increases to 62.6 molm-3 near anode within 6.7 s with a current density of 200 Am-2, there is no co-deposition of uranium and neptunium occurred. In addition, it is proved that the pulse electrorefining does not improve the recovery of uranium compared with galvanostatic electrorefining with a corresponding average current.

In recent years, lightweight high-entropy alloys (LHEAs) have attracted a lot of attention within the hydrogen storage domain. However, their gravimetric hydrogen storage capacities (HSC) are relatively low and need to be improved significantly. In this work, based on Ti24V18Cr18 alloy, five lightweight high-entropy alloys, i.e., Mg10Ti24V18Cr8, Mg12Ti24V18Cr6, Mg14Ti24V18Cr4, Mg16Ti24V18Cr2 and Mg18Ti24V18, are designed, and their hydrogen storage properties are explored. These compounds are found to be energetically and lattice dynamically stable. Besides, with the increasing Mg content, the gravimetric HSCs of Mg-containing high entropy alloys are remarkably increased. Especially, the gravimetric HSC of Mg18Ti24V18 is as high as 6.03 wt%. Moreover, the dehydrogenation temperature of these compounds is 78-106 K smaller than that of MgH2. The presented results, thus, suggest that these Mg-containing LHEAs have great potential as hydrogen storage materials.

The advancement of bulk metallic glasses (BMGs) for extreme-environment applications is hindered by limited understanding of their elastic behavior and structural stability under high pressure. This study presents a comprehensive study of the high-pressure elastic properties of Ir-Ni-Ta BMGs using in-situ ultrasonic interferometry. Two representative compositions, Ir29Ni29Ta42 and Ir33Ni28Ta39, exhibit pronounced elastic stiffening and robust structural integrity under compression, with zero-pressure bulk moduli of 213.7 and 245.0 GPa, shear moduli of 67.6 and 71.3 GPa, and Vickers hardness values of 10.1 and 10.4 GPa, respectively. Remarkable ductility is confirmed by high Pugh's (3.16 and 3.44) and Poisson's (0.357 and 0.367) ratios, indicating densely packed, cluster-dominated amorphous networks. Superior elastic performance in Ir33Ni28Ta39 results from higher Ir content, which enhances 5d electron-driven covalent bonding and reduces molar volume (9.12 vs. 9.52 cm3/ mol), yielding a stiffer structure. This difference in atomic packing manifests in distinct pressure derivatives of the bulk modulus (B ' = 3.13 vs. 4.63), highlighting composition-dependent compressional responses. Furthermore, Debye temperature analysis predicts pressure-induced elevation of the glass transition temperature, confirming enhanced thermal stability. These findings establish direct correlations between atomic-scale bonding, elasticity, and thermal robustness in BMGs, guiding the rational design of amorphous alloys for extreme conditions.

This study employs density functional theory with Hubbard U correction (DFT+U) to investigate the influence of the weberite motif on the elastic moduli, Debye temperature, thermal conductivity, and electronic structures of actinides (Th, U, Np, Pu, and Am) in disordered Gd2Zr2O7. The key distinction between the disordered and ordered Gd2Zr2O7 phases lies in the presence of the weberite motif. The incorporation of actinides into Gd2Zr2O7 containing the weberite motif results in a slight reduction in the elastic moduli and thermal conductivity, compared to actinides incorporated into Gd2Zr2O7 without the weberite motif. This suggests that the actinide-doped disordered Gd2Zr2O7 retains its thermophysical stability. Additionally, the inclusion of actinides into the Gd2Zr2O7 phase with weberite motifs significantly lowers the Debye temperature relative to actinide incorporation in Gd2Zr2O7 without the motif. This observation indicates a higher thermal expansion coefficient for actinide doping in disordered Gd2Zr2O7, which may be more favorable for the application of pyrochlores in extreme environments. These findings highlight the critical role of the weberite motif in influencing the mechanical and thermophysical properties of actinide-doped disordered pyrochlores.

Controlling grain behavior during high pressure and high temperature (HPHT) sintering is crucial for synthesizing high-performance bulk ceramic materials. Chromium carbide (Cr3C2), a representative transition metal carbide ceramic, finds extensive industrial applications owing to its exceptional combination of properties. In this study, the intricate grain behaviors in Cr3C2 under 15 GPa/25-1700 degrees C are revealed by HPHT methods. It is found that the mechanical and elastic properties of Cr3C2 exhibit a significant dependence on temperatureinduced grain behavior. Particularly, the mechanical properties of Cr3C2 exhibit abnormal softening at 15 GPa/1200 degrees C and 15 GPa/1500 degrees C. Through characterization and analysis of the microstructure, it is confirmed that the significant change in mechanical properties stems from the abnormal sintering behaviors of distinctive competitive behavior of grain refinement and growth. The findings highlight the significant influence of the competitive behavior on microstructural evolution, which exhibits strong correlations with the mechanical properties.