Linsen Zhou

Helium bubbles are a major microstructural cause of mechanical degradation in metallic materials exposed to fusion and tritium storage environments. In palladium, a representative tritium storage material, helium produced by tritium decay can aggregate into nanoscale bubbles, inducing local stress concentrations, dislocation activity, and plastic instability. Here, high-throughput molecular dynamics simulations and physics-informed machine learning are combined to investigate the tensile response and defect evolution of helium-bubble-containing palladium under the coupled effects of temperature, strain rate, bubble radius, and helium-to-vacancy ratio (He/V). Increasing temperature markedly reduces the peak stress, whereas larger helium bubbles and higher helium-to-vacancy ratios intensify local structural instability and promote defect propagation. Higher strain rates produce pronounced strain-rate strengthening. Atomistic analyses further show that helium bubbles promote local dislocation nucleation, vacancy aggregation, and stacking fault tetrahedron formation, thereby driving the transition from elastic load-bearing to plastic damage. A physics-informed support vector regression model, incorporating Johnson-Cook-type constitutive trends, is then developed to predict peak stress across complex conditions. Compared with conventional support vector regression, which shows poor extrapolation performance (R² = -2.200, root-mean-square error = 2.425 GPa), the physics-informed support vector regression model achieves substantially improved extrapolation stability and physical consistency (R² = 0.910, root-mean-square error = 0.406 GPa). These findings clarify the coupled mechanisms of helium-bubble-induced degradation in palladium and provide a physically constrained framework for limited-data property prediction in materials for nuclear environments.

To solve the long-standing coupled degradation problem of disproportionation and impurity poisoning in hydrogen storage materials for the International Thermonuclear Experimental Reactor (ITER), this study aims to develop a high-stability hydrogen storage strategy and verify its effectiveness. A synergistic strategy integrating bulk nanostructuring with Pd-based surface/interface engineering is proposed. Specifically, single-crystalline ZrCo nanoparticles were synthesized by a chemical precipitation-magnesiothermic reduction method, and then transformed into a core-shell Pd@nanoZrCo composite to simultaneously optimize the bulk-phase stability and surface reaction kinetics of the material. Nanostructuring can significantly suppress bulk disproportionation and reduce the hydrogen desorption barrier, but it also causes Co surface segregation during cycling, leading to gradual capacity decay. In contrast, Pd modification not only accelerates hydrogen uptake through a spillover-mediated pathway but also effectively alleviates impurity poisoning, which is attributed to Pd’ s high hydrogen permeability and intrinsically weak affinity for CO. The experimental results show that the optimized 1.5Pd@nanoZrCo composite exhibits significantly enhanced capacity retention and disproportionation resistance in CO-containing atmospheres, with its performance improved iby an order of magnitude compared with the unmodified ZrCo material. The innovation of this study lies in constructing a cooperative design paradigm that couples bulk structural regulation with interfacial engineering, which not only solves the key technical bottleneck of hydrogen storage materials for ITER but also provides a universal and applicable technical route for the development of highly stable hydrogen storage materials in advanced hydrogen energy systems, thus possessing important academic value and engineering application prospects.

Addressing CO poisoning challenges in Zr2Fe-based tritium getters for fusion reactors, this work establishes Mn doping as an effective mitigation strategy through combined DFT and Sieverts investigations. The DFT computations show reduced CO adsorption site occupation upon Mn incorporation, concurrently facilitating H2 dissociation on CO-precovered surfaces via d-state modulation and active site generation. Crucially, CO adsorption manifests bifunctional surface dependence: weakly interacting CO-Mn pairs induce reconstruction that further lowers dissociation barriers, while strongly bound CO-Fe configurations completely suppress hydrogen activation on undoped surfaces. Experimental validation under 99.5% H2/0.5% CO environments confirms Zr2Fe0.9Mn0.1 exhibits faster absorption kinetics and higher capacity versus pristine Zr2Fe. These findings reveal a tripartite mechanism where Mn-induced electronic tuning, CO-triggered geometric restructuring, and competitive adsorption collectively enable exceptional poisoning resistance of Zr2Fe, providing actionable design principles for advanced tritium recovery system.

Catalytic oxidation plays a crucial role in the efficient treatment of hydrogen isotopes, with the key technical challenge being the development of high‐performance catalysts to enhance isotope removal efficiency, thereby reducing environmental pollution and ensuring public radiation safety. Herein, the strategic control of platinum nanoclusters confined within silicalite‐1 zeolites is reported to enhance the high removal efficiency for hydrogen isotopes under low‐temperature conditions for the first time. Incorporating a single lanthanum oxide (LaO _x ) into Pt nanoclusters adapts the local charge of adjacent Pt atoms, significantly altering their electronic structure. The existence of individual LaO _x species is confirmed by X‐ray absorption spectroscopy and aberration‐corrected electron microscopy, and the performance enhancement mechanism is further probed by theoretical calculations. This embedded single LaO _x both facilitates local charge adjustment and supplies abundant active oxygen species, leading to performance enhancement by reducing the energy barrier of rate‐determining step (O ^* + H → OH ^* ), in accordance with the Mars‐van Krevelen mechanism. Consequently, during a surprisingly long‐term restart performance test (≈267 d), the PtLaOx@S‐1 maintained a high conversion rate over 99% at 50 °C and a space velocity of 48,000 mL·g ⁻¹ ·h ⁻¹ . This study highlights the potential of individual LaO _x sites for enhancing hydrogen isotope oxidation.

Zr2Fe alloy exhibits the advantages of being tritiated water-free and easy to recover in the form of reversible metal hydrides, which make it an ideal material for the trapping of hydrogen isotopes. However, the drawback easily poisoned by impurity gases is the bottleneck for its application. Although significant advances are achieved in the exploration the effects of oxygen on the hydrogen adsorption performance of Zr2Fe, a microscopic-level explanation of the inherent influencing mechanism is lacking. Herein, we performed detailed DFT analysis to systematically study the oxygen interaction with Zr2Fe. The results show that O2 is dissociatively adsorbed at the hollow site. The oxygen atoms are found to interact strongly with Zr and Fe atoms. The climbing-image nudged elastic band results show that the O atoms occupy the active sites and subsequently hinder the H diffusion to the interior. Our findings are beneficial for understanding and estimating the hydrogen storage capability of alloy materials based on Zirconium.

Interfacial hydrogen transfer between metal particles and catalyst supports is a ubiquitous phenomenon in heterogeneous catalysis, and this occurrence on reducible supports has been established, yet controversies remain about how hydrogen transfer can take place on nonreducible supports, such as silica. Herein, highly dispersed Pt clusters supported on a series of porous silica materials with zeolitic or/and amorphous frameworks were prepared to interrogate the nature of hydrogen transfer and its promotional effect on H₂-HDO isotope catalytic exchange. The formation of zeolitic frameworks upon these porous silica supports by hydrothermal crystallization greatly promotes the interfacial hydrogen bidirectional migration between metal clusters and supports. Benefiting from this transfer effect, the isotope exchange rate is enhanced by 10 times compared to that on the amorphous counterpart (e.g., Pt/SBA-15). In situ spectroscopic and theoretical studies suggest that the defective silanols formed within the zeolite framework serve as the reactive sites to bind HDO or H₂O by hydrogen bonds. Under the electrostatic attraction interaction, the D of hydrogen-bonded HDO scrambles to the Pt site and the dissociated H on Pt simultaneously spills back to the electronegative oxygen atom of adsorbed water to attain H-D isotope exchange with an energy barrier of 0.43 eV. The reverse spillover D on Pt combines with the other H on Pt to form HD in the effluent. We anticipate that these findings are able to improve our understanding of hydrogen transfer between metal and silica supports and favor the catalyst design for the hydrogen-involving reaction.

State-to-state photodissociation dynamics of D2S in its first absorption band were explored by utilizing recently developed diabatic potential energy surfaces (PESs). Quantum dynamics calculations, involving the first two strongly coupled 1 A&D'states, were executed employing a Chebyshev real wavepacket method. The nonadiabatic channel via the conical intersection (CI) is facile, direct, and fast, leading to the production of rotationally and vibrationally cold SD(X 2 pi). The calculated absorption spectrum, product state distributions, and angular distributions are in reasonable agreement with the experimental results, although some discrepancies exist at 193.3 nm. Compared with H2S, there are obvious isotope effects on rotational state distributions for D2S photodissociation in its first absorption band. Moreover, we scrutinize the variation of product state distributions as a function of photon energy and the vibrational mediated photodissociation of the parent molecule. Due to the diverse shapes of the three fundamental vibrational wave functions, photoexcited wavepackets access distinct segments of the upper-state PES, resulting in a disparate absorption spectrum and ro-vibrational distributions via the nonadiabatic transition. This study provides a comprehensive figure of the isotopic effect and wavelength dependence on the photofragmentation behaviors from D2S photodissociation, which should attract more experimental and theoretical attention to this prototypical system.

New accurate diabatic PESs for the first two exited singlet states of H₂S and photodissociation dynamics in the first absorption band.