Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Corrosion Science  

The influence of temperature on the hydrogen gas embrittlement (HGE) susceptibility of X80 is unclear. In this work, mechanical test results revealed the enhanced HGE susceptibility with the decreasing temperature ranging from 333 K to 263 K. At lower temperatures, quasi-cleavage characteristics appeared on crack surfaces and plasticity suppression was further enhanced. Increased dislocation trapping capacity with decreasing temperature was demonstrated by finite element analysis and first-principles molecular dynamics calculations. At the investigated temperature, hydrogen could be sufficiently supplied to dislocations. Therefore, hydrogen trapping sites exhibited a higher concentration than lattice hydrogen and played a dominant role in determining the overall hydrogen distribution within the material. The strong trapping ability of dislocations at lower temperatures could increase the hydrogen concentration in high-density dislocation regions, including the crack tip. It recommends that the HGE of X80 for hydrogen delivery shall be evaluated at a lower temperature instead of room temperature which usually be used.

DOI： 10.1016/j.corsci.2025.112928

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Publisher：Journal of Mechanical Science and Technology  

With the growing interest in hydrogen-enriched natural gas transport, understanding the effects of hydrogen on pipeline materials has become essential. This work investigated the mechanical performance of GB20# pipeline steel in an actual hydrogen-enriched natural gas environment, assessing tensile properties, fatigue life, and fracture toughness across varying hydrogen partial pressures. It was found that, compared to pure natural gas, the plasticity and fatigue life of both the base and weld metals significantly deteriorated in hydrogen-enriched conditions, with degradation levels increasing with hydrogen partial pressure. Additionally, fracture toughness in both metals declined in hydrogen-enriched environments. The weld metal displayed slightly lower sensitivity to hydrogen embrittlement than the base metal, may be due to the finer grain structure. These findings contribute valuable insights into the behavior of natural gas pipeline steels under hydrogen exposure, essential for safe hydrogen-blended natural gas applications.

DOI： 10.1007/s12206-025-2401-9

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Publisher：Journal of Materials Chemistry A  

To further enhance the performance of perovskite solar cells (PSCs), a more comprehensive analysis of the mechanisms through which organic molecules induce defect passivation and enhance hole extraction is essential. In this study, we employ several organic molecules with varying π-conjugation lengths to examine how factors such as their molecular desorption, energy levels, and radical-cation stability affect defect passivation, hole extraction, and the overall PSC performance. Our results show that passivation molecules with extended π-conjugation suppress molecular desorption from the perovskite surfaces during overlayer spin-coating and improve energy-level alignment at interfaces, thereby enhancing PSC efficiency through improved defect passivation and hole extraction. Additionally, extended π-conjugation improves radical-cation stability, contributing to greater device durability. Among the defect passivation materials studied, 2-(3-ethylamine)benzothieno[3,2-b]benzothiophene hydroiodide (BTBTAI) can provide the most significant improvements in these factors, increasing the initial efficiency from 22.7% to 24.6% and raising the efficiency retention from 61% to 85% after 1000 hours of continuous light illumination at 25 °C in formamidinium lead iodide-based PSCs. Reports on defect passivation from the perspectives of molecular desorption and cation stability are extremely limited. Therefore, these findings deepen the understanding of PSC operating mechanisms and offer valuable insights for developing design guidelines for future defect passivation materials with even higher device performance.

DOI： 10.1039/d5ta00754b

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Applied Energy  

The deployment of renewable energy and the implementation of intelligent energy management strategies are crucial for decarbonizing Building Energy Systems (BES). Although data-driven Deep Reinforcement Learning (DRL) has achieved recent advancements in optimizing BES, significant challenges remain, such as the lack of studies addressing the observation space of time series data and the scarcity of interpretability. This paper first introduces future forecast information into the DRL algorithm to form the observation space for time series data. It employs Gated Recurrent Unit(GRU) and Transformer networks coupled with the DRL algorithm for operational control of a Building-Integrated Photovoltaic and Battery(BIPVB) system. Additionally, it aims to enhance the interpretability of the model regarding global and local feature importance by integrating the state-of-the-art Shapley Additive Explanations (SHAP) technique with the developed DRL model. All results were validated and tested on an open-source, real-world BIPVB system, showing that incorporating forecast information can reduce operational costs by 3.56%, while using GRU and Transformer networks to handle time-series data can further reduce costs by over 10%. The results of the SHAP value analysis demonstrated the importance of future electricity prices in forecast information for optimization, revealing the model's complex nonlinear relationships. Additionally, this study provided interpretability for a single episode instance based on the SHAP method. Overall, the study offers an accurate, reliable, and transparent deep reinforcement learning model, along with an insightful framework for handling time-series observations in DRL.

DOI： 10.1016/j.apenergy.2025.125387

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Language：English   Publisher：Advanced Materials  

Exploiting the self-assembled molecules (SAMs) as hole-selective contacts has been an effective strategy to improve the efficiency and long-term stability of perovskite solar cells (PSCs). Currently, research works are focusing on constructing SAMs on metal oxide surfaces in p-i-n PSCs, but realizing a stable and dense SAM contact on halide perovskite surfaces in n-i-p PSCs is still challenging. In this work, the hole-selective molecule for n-i-p device is developed featuring a terephthalic methylammonium core structure that possesses double-site anchoring ability and a matching diameter (6.36 Å) with the lattice constant of formamidinium lead iodide (FAPbI<inf>3</inf>) perovskite (6.33 Å), which facilitates an ordered and full-coverage SAM atop FAPbI<inf>3</inf> perovskite. Moreover, theoretical calculations and experimental results indicate that compared to the frequently used acid or ester anchoring groups, this ionic anchoring group with a dipolar charge distribution has much larger adsorption energy on both organic halide terminated and lead halide terminated surfaces, resulting in synergistic improvement of carrier extraction and defect passivation ability. Benefiting from these merits, the efficiency of PSCs is increased from 21.68% to 24.22%. The long-term operational stability under white LED illumination (100 mW cm⁻²) and at a high temperature of 85 °C is also much improved.

DOI： 10.1002/adma.202414576

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Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

This study investigated the pressure-dependent CO<inf>2</inf> effect on the hydrogen embrittlement of X80 and GB20# pipeline steels by combining experiments and first-principles calculations. Results revealed that the CO<inf>2</inf> effect enhanced the fatigue crack growth for GB20# steel in 10 MPa CO₂-enriched hydrogen mixtures. However, the improved degree by the CO₂ effect at 10 MPa was less pronounced than at 0.4 MPa, which was found for the first time. This was attributed to the decreased adsorption rate of CO₂ on iron as hydrogen pressure increased. Therefore, in high-pressure CO₂-enriched hydrogen mixtures, CO<inf>2</inf> could not significantly accelerate the inherent rapid hydrogen uptake at high pressure.

DOI： 10.1016/j.ijhydene.2024.10.032

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Authorship：Corresponding author  

Authorship：Lead author  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Utilizing the existing natural gas grid presents a promising method for transporting hydrogen on a large scale. However, the effects of natural gas and its impurities on hydrogen-assisted cracking in pipeline steel have not been adequately studied. This study aims to investigate the fatigue performance of X80 pipeline steel in hydrogen-enriched natural gas (HENG) environments and in mixtures containing the impurity CO2. This is achieved through fatigue crack growth rate (FCGR) tests and density functional theory (DFT) calculations. The experimental results show that the FCGR in H2 is slightly faster than that in HENG, whereas it is slower than that in the N2/CO2/H2 mixtures. The enhanced FCGR by CO2 further increases with the increasing CO2 content. DFT computational results indicate that the adsorbed CO2 on the iron surface significantly accelerates the migration of H atoms from surface to subsurface. This promotes the entry of hydrogen into the steel.

DOI： 10.1016/j.ijhydene.2024.04.116

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Hydrogen Energy  

The characteristics of hydrogen trapping and hydrogen distribution for the unstrained and strained X80 pipeline steel were investigated in this work. Ultra-high vacuum thermal hydrogen desorption spectroscopy tests were conducted on the hydrogen pre-charged specimens to study the properties of hydrogen trapping under the influence of plasticity. Results showed that the binding energy of the dislocation trap generated by plastic deformation was 28.30∼33.84 kJ/mol, increasing with the increase of strain. As the deformation in the material increased, the number of dislocation traps as well as the hydrogen trapped in the dislocations increased, leading to a higher hydrogen content in the strained specimens. Additionally, finite element simulations were employed to elucidate the properties of hydrogen distribution as affected by plasticity. The binding energy of dislocation trap had a significant effect on the calculated maximum hydrogen concentration in the specimen. Hydrogen trapped at the dislocations during the plastic deformation stage dominated the maximum total hydrogen concentration in X80, which was consistently in the region of greatest strain and increased with the increasing strain and binding energy of hydrogen trapping.

DOI： 10.1016/j.ijhydene.2023.12.272

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Language：English   Publishing type：Research paper (scientific journal)  

<jats:p>Austenitic stainless steels (γ-SS) play an important role in the storage of high-pressure hydrogen. However, hydrogen embrittlement (HE) can significantly degrade the mechanical properties of γ-SS. Measuring the distribution of hydrogen in γ-SS is a vital way to learn about HE. In this paper, scanning Kelvin probe force microscopy (SKPFM) and thermal desorption spectroscopy (TDS) have been utilized to analyze the distribution and diffusion of hydrogen in pre-strained SUS316L. Additionally, the McNabb–Foster model is employed to calculate hydrogen in the lattice and phase boundaries along the sample’s thickness direction. The results demonstrate that the combination of SKPFM and TDS is an effective approach for studying hydrogen distribution and diffusion in metals. It was observed that hydrogen segregation occurs at the boundary between the martensitic (α′) and austenite (γ) phases. The inhibitory effect of the oxide film on hydrogen diffusion is more significant at lower temperatures. However, it should be noted that the McNabb–Foster model exhibits relatively high accuracy in predicting hydrogen desorption at higher temperatures while disregarding the influence of the native oxide film.</jats:p>

DOI： 10.3390/en16207126

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier {BV}  

DOI： 10.1016/j.corsci.2022.110594

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DOI： 10.16085/j.issn.1000-6613.2021-1438

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Publishing type：Research paper (international conference proceedings)   Publisher：American Society of Mechanical Engineers  

<jats:title>Abstract</jats:title>
<jats:p>This study aims to investigate the hydrogen-induced cracking behavior of the cylinder of 4130X hydrogen storage vessel in a 45 MPa high-pressure hydrogen environment under the synergistic influence of hydrogen and crack depth. Firstly, finite element analysis was performed via a modified hydrogen diffusion/plasticity coupled model to study the coupling behavior of hydrogen diffusion and plastic deformation in a hydrogen storage vessel with a crack. Then we used the modified hydrogen diffusion/plasticity coupled model to study the effect of crack depth on the hydrogen-induced cracking behavior in the hydrogen storage vessel. Results show that the hydrogen is mainly concentrated in the trap at the crack tip of the vessel, and the crack tip is always the position with the highest total hydrogen concentration. The distribution of plastic strain and trap hydrogen concentration on the crack surface is small along the axial direction of the cylinder, but large along the radial direction of the cylinder. With the increase of the initial crack depth, the pressure difference corresponding to the crack propagation from radial direction to unstable propagation and the depth of the crack propagation show a decreasing trend, and the hydrogen pressure of unstable propagation also decreases gradually. The greater the depth of cylinder crack, the more difficult it is to prevent cylinder failure.</jats:p>

DOI： 10.1115/PVP2022-84572

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Publishing type：Research paper (international conference proceedings)   Publisher：American Society of Mechanical Engineers  

<jats:title>Abstract</jats:title>
<jats:p>Carburizing treatment can improve the carbon content of the workpiece material, and obtain higher contact fatigue strength, bending fatigue strength, as well as higher surface hardness. After carburizing, the existence of carbon atoms can hinder the adsorption and diffusion of hydrogen, thus reducing the hydrogen embrittlement. First-principles plane wave calculations based on spin-polarized density-functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption and permeation of hydrogen on iron in the bulk with carbon interstice solid solution and carbon substitution solid solution. Considering that hydrogen diffusion is faster in martensitic tissue, bcc-Fe structure is selected for the model. The results show that the hydrogen diffusion rate Di in the interstice solid solution is higher than Ds in the substitution solid solution. The formation of substitution solid solution is promoted by more vacancies in the lattice. When the vacancy is occupied by carbon atoms, the hydrogen diffusion rate is reduced. This phenomenon is more obvious for Fe48C16 structure with higher carbon ratio. Besides, charge density diagram and state density analysis are also consistent with this conclusion. Therefore, during carburizing, Increasing the content of carbon and carbon substituted solid solution can reduce the penetration of hydrogen in the material.</jats:p>

DOI： 10.1115/PVP2022-84462

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Authorship：Lead author   Language：Chinese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.scriptamat.2020.08.011

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.apsusc.2020.147050

Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.ijhydene.2020.02.125

Language：English   Publishing type：Research paper (scientific journal)  

DOI： https://doi.org/10.1016/j.matlet.2019.02.089

Presentation type：Poster presentation  

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