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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Engineering Failure Analysis  

The degradation of mechanical properties in hydrogen pipeline welded joints caused by hydrogen embrittlement (HE) poses significant safety challenges. This study investigates the low-cycle fatigue performance and fracture characteristics of welded joints made from 20# steel in high-pressure hydrogen environments. Transverse specimens of welded joint including the weld metal (WM), heat-affected zone (HAZ) and base metal (BM) were subjected to cyclic loading under varying hydrogen pressures. The strain ratio was 0.1 and the strain amplitude was 0.3%. The results show that in the 0.4 MPa hydrogen environment, the fatigue life of the specimen decreased to a maximum reduction of 33.94% compared to that in the 0.4 MPa nitrogen reference environment. Furthermore, when the hydrogen pressure was increased to 4 MPa, the fatigue life reached a maximum reduction of 13.92% relative to the reference environment. The fracture surfaces of specimens tested in hydrogen are notably flatter, with the dimpled features characteristic of ductile rupture being severely suppressed. Furthermore, a statistical evaluation of fracture sites across multiple specimens identified a distinct shift in failure location. While fractures in nitrogen occurred without a clear positional preference, a strong propensity for crack initiation and final fracture within the HAZ was consistently observed under hydrogen exposure. These findings underscore the HAZ as the critical weak link and primary risk zone for fatigue failure in hydrogen-transport pipelines.

DOI： 10.1016/j.engfailanal.2026.110738

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Corrosion Science  

Inhibition of hydrogen embrittlement (HE) by gas inhibitors is one of the effective methods for preventing hydrogen-induced damage. The objective of this study is to quantitatively evaluate the coupled inhibitory effects of mCO+nO<inf>2</inf> on HE of X80 steel in multicomponent gas environments, and to combine with Density Functional Theory (DFT) calculations to elucidate its underlying microscopic mechanisms. Results show that the CO+O<inf>2</inf> combination (500 vppm CO+500 vppm O<inf>2</inf>) has a stronger inhibitory effect on HE compared to CO or O<inf>2</inf> (1000 vppm) acting alone, which inhibits the fatigue crack growth rate (FCGR) by more than 80% and increases the fracture toughness (FT) by nearly five times. At the range of stress intensity factor ΔK＜28 MPa·m^1/2, the introduction of trace impurities of 1000 vppm CO+ 1000 vppm O<inf>2</inf> in an 8 MPa-20% H<inf>2</inf> environment completely eliminates the effects of H<inf>2</inf> on FCGR. Molecular Dynamics (MD) simulation results suggest that compared with CO or O<inf>2</inf> alone, the CO+O<inf>2</inf> combination more easily forms a higher impurity molecule coverage, thus better inhibiting the dissociation of hydrogen molecules. DFT results indicate that the combination of CO+O<inf>2</inf> forms a lower energy barrier at high coverage compared with CO or O<inf>2</inf> alone, making it easier for impurity molecules to enter the potential field upon iron surface, thereby enhancing the influence of pre-adsorbed impurity molecules on the adsorption and dissociation behavior of hydrogen on the Fe (110) plane.

DOI： 10.1016/j.corsci.2026.113787

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Authorship：Last author,　Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Engineering Failure Analysis  

With the widespread application of hydrogen-blended natural gas pipelines, evaluating the hydrogen compatibility and residual life of compressor impeller has become essential for ensuring the safe and reliable operation of hydrogen pipeline systems. In this study, fatigue crack growth rate (FCGR) and fracture toughness tests were carried out on FV520B, a representative impeller blade material, under various simulated hydrogen-blended natural gas environments. Results show that under 12 MPa 20 vol% H<inf>2</inf>-blended environment, the FCGR increases to about 24 times that of the nitrogen environment, and the fracture toughness (K<inf>IH</inf>) decreases to only 25% of that in nitrogen. Moreover, higher stress ratios and total pressures further increase the crack growth rate. Based on these experimental data, finite element analyses based on adaptive grid technique were conducted to assess the effects of hydrogen-blended ratio and stress ratio on impeller residual life through a damage tolerance evaluation method. The results show that under the 20 vol% H<inf>2</inf>-blended environment, the residual life of the blade with an initial crack depth of 0.1 mm at stress ratio (R) of 0.1 was 12,874 cycles − only half of that under the 10 vol% H<inf>2</inf>-blended environment. Additionally, when R = 0.5 and 0.7, the life of blades were 22,603 and 19,902 cycles, respectively, due to complex influence of stress ratio on FCGR. These findings highlight the need for rigorous hydrogen-compatibility evaluations and careful control of blending ratios and stress conditions to ensure the safe and reliable operation of impellers in hydrogen-blended environments.

DOI： 10.1016/j.engfailanal.2026.110596

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Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Letters  

With the increasing use of hydrogen energy, hydrogen embrittlement (HE) of high-strength steels has become a critical concern. In this work, fracture toughness tests were conducted on SCM435 steel to clarify the effect of pressure and strain rate on water-mitigated HE. The results show that adding 65 volume ppm H<inf>2</inf>O to hydrogen significantly reduced the severity of HE. The extent of mitigation depended on H<inf>2</inf>O partial pressure and strain rate, where the suppression was more effective at higher H<inf>2</inf>O partial pressure and slower loading rate. Fracture surface observations showed that dry hydrogen promoted quasi-cleavage fracture and suppressed stretch zone formation. In contrast, humid hydrogen promoted dimples and restored the stretch zone, indicating enhanced ductile crack initiation. Control tests in N<inf>2</inf> + H<inf>2</inf>O confirmed that H<inf>2</inf>O alone did not cause embrittlement. A possible interpretation based on our previous density functional theory calculations, the H<inf>2</inf>O effect is that adsorbed H₂O molecules increase the activation barrier for hydrogen adsorption on the Fe surface, thereby reducing hydrogen ingress.

DOI： 10.1016/j.matlet.2025.140039

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

Hydrogen energy is crucial for the transition to a low-carbon economy, but high-pressure hydrogen can cause severe embrittlement in pipeline steels. The presence of CO₂ impurities in hydrogen-blended natural gas may significantly influence the hydrogen embrittlement (HE) behavior. This work systematically investigates the influence of CO₂ partial pressure on the hydrogen embrittlement of pure iron in high-pressure environments using slow strain rate tensile (SSRT) and fatigue crack growth rate (FCGR) tests, hydrogen permeation experiments, and first-principles molecular dynamics (FPMD) simulations. The results show that, compared to pure hydrogen, as CO₂ concentration increases, the elongation of pure iron first decreases then increases, while FCGR increases then decreases, with the most significant HE promotion occurring at 0.2 MPa CO₂. The consistency between SSRT and FCGR outcomes can be explained by the dual role of CO₂ in hydrogen permeation. At low CO₂ concentrations, CO₂ promotes the migration of hydrogen atoms toward the subsurface, which enhances hydrogen embrittlement; at high CO₂ concentrations, CO₂ occupies more metal surface adsorption sites, inhibiting hydrogen adsorption and coordination on the metal surface, thereby inhibiting hydrogen embrittlement.

DOI： 10.1016/j.corsci.2025.113555

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS Nano  

The development of monolayer hole-selective contacts has proven to be an effective strategy for enhancing the performance and scalability of inverted perovskite solar cells (PSCs). However, current monolayer molecules often suffer from limited charge separation and extraction capabilities due to their small π-conjugated domains, localized carrier orbitals, and weak interfacial binding with substrates. Here, we report a molecular design featuring a double donor–acceptor (D–A) conjugated architecture with an enhanced push–pull effect, spatially separated carrier orbitals for efficient hole extraction and electron blocking, bifacial anchoring for strong binding to both metal oxide substrates and perovskite layers, and a twisted π-skeleton that suppresses self-aggregation and ensures homogeneous monolayer distribution. By replacing conventional [2-(9H-carbazol-9yl)ethyl]phosphonic acid (2PACz) with this double D–A-type monolayer, the PCE improves from 23.69% to 25.61% (certified 25.11%) in small-area PSCs, while large-area perovskite modules (active area of 10.04 cm²) achieve a high PCE of 21.40%. Notably, the devices exhibit excellent operational stability under continuous illumination (100 mW cm^–2) at an elevated temperature (85 °C), maintaining 84.9% of the initial efficiency after 1000 h.

DOI： 10.1021/acsnano.5c21709

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Nature Communications  

Self-assembled molecules are widely used as bottom interfacial layers in inverted perovskite solar cells, yet their application to perovskite top surfaces remains poorly understood. Here, we develop two self-assembled molecules for perovskite surface modification and interfacial optimization with the hole transport layer. Through solvent engineering, ordered and uniform molecular packing is achieved on the perovskite surface. These molecules optimize surface energetics and promote efficient hole transfer when coupled with a homologous hole transport layer. Their large molecular dipoles tune interfacial energy alignment and reduce energetic offsets, thereby accelerating charge extraction from the perovskite layer. This dipole-driven interfacial modulation is effective in both normal and inverted device architectures. As a result, a power conversion efficiency of 26.18% (certified 26.23%) is achieved in normal-structure devices, together with improved operational stability under maximum power point tracking. This work establishes a viable strategy for perovskite surface engineering using self-assembled molecules.

DOI： 10.1038/s41467-026-69198-2

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Language：English  

DOI： 10.2139/ssrn.6908626

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Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

Ru nanoparticles reconstruct water networks on RANEY® Ni, decreasing local pH near cathode to inhibit passivation. The cathode achieves 10 A cm ⁻² at 2.3 V with 2500 hours stability at 1.0 A cm ⁻² .

DOI： 10.1039/d5ee04506a

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Hydrogen Energy  

An investigation of autofrettage on a 100 MPa 4130X hydrogen vessel was conducted in this paper. The evolution of stress intensity factor (SIF) and actual stress ratio (R<inf>k</inf>) of a cylinder crack under varying overstrain levels were studied, followed by evaluation of fatigue failure cycles at several typical points to determine the overall vessel fatigue life. The results indicate that the overall stress profile is considerably changed after autofrettage, which has a major influence on critical positions that determine the vessel fatigue life. The cylinder part, generally accepted as the weakest position in current studies, ceases to be the critical zone as the overstrain level raises to 40 %, and the critical positions shift towards the transition areas of cylinder-dome and dome-nozzle above 60 %, which should be paid special attention to when considering autofrettage. For the dome part, assessment should be made based on the maximum principal stress direction rather than simply using the axial initial crack. The overall vessel fatigue life increases with overstrain levels and saturates at 80 % overstrain level, with hardly further gains at higher levels.

DOI： 10.1016/j.ijhydene.2025.152315

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Hydrogen Energy  

This study introduces a novel method integrating ReaxFF molecular dynamics with the grand canonical Monte Carlo (GCMC) method to investigate the adsorption and dissociation of hydrogen on the α-Fe(110) surface under the coupling effect of pressure and temperature. The vacuum layer of the slab model is connected to a virtual hydrogen reservoir, maintaining a constant H<inf>2</inf> molecule count during reactions. enabling direct analysis of hydrogen behavior on Fe under specified conditions. Studies have shown that the dissociation of hydrogen on the α-Fe(110) surface can be described using the Langmuir equation. Counterintuitively, at lower pressures, physical adsorption predominantly governs the number of hydrogen atoms entering the α-Fe(110) surface in a steady state, with a stable adsorption layer forming at lower temperatures to enhance hydrogen uptake. Conversely, at higher pressures, dissociation prevails, with an elevated dissociation probability at higher temperatures driving more hydrogen atoms entering the α-Fe(110) surface.

DOI： 10.1016/j.ijhydene.2025.152012

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

As hydrogen emerges as a key energy carrier for carbon-neutral technologies, mitigating gaseous hydrogen embrittlement (GHE) in existing structural materials becomes a critical challenge for a seamless transition to a hydrogen economy, alongside the development of new hydrogen embrittlement-resistant materials. This work combined experimental studies and first-principles calculations to investigate the role of water vapor in mitigating GHE in the SCM435 low alloy steel. Fatigue crack growth (FCG) tests revealed that adding 991 vol ppm water vapor to a hydrogen environment markedly suppressed hydrogen-induced acceleration in the SCM435 steel. The crack growth rate in moist hydrogen was reduced by approximately 8 times compared to dry hydrogen for both strength levels, reaching levels comparable to those in air. Scanning electron microscopy analysis indicated that fracture surfaces in the moist hydrogen exhibited ductile transgranular fracture, contrasting with the quasi-cleavage and intergranular fracture features observed in dry hydrogen, confirming the protective effect of water vapor. Computational modeling showed that water molecules tended to adsorb on the clean Fe(110) surface in molecular form with an adsorption energy of −0.32 eV. Increasing water coverage raised the hydrogen dissociation barrier from 0 to 0.39 eV, reducing the dissociation rate constant by over 10⁷. These results suggest that trace amounts of water vapor can act as a practical GHE inhibitor, offering new perspectives for enhancing the reliability of structural materials in hydrogen-rich environments.

DOI： 10.1016/j.corsci.2025.113252

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Physical Chemistry C  

Rare-earth orthoferrites (ReFeO<inf>3</inf>) exhibit multifaceted properties, including weak ferromagnetism, potential ferroelectricity, and magnetoelectric coupling. This study systematically investigated Y<inf>1–x</inf>Gd<inf>x</inf>FeO<inf>3</inf>(x = 0.2–1.0) synthesized via hydrothermal methods to understand how Gd substitution tunes these multifunctional properties. X-ray diffraction confirms single-phase orthorhombic structures (Pnma) with lattice expansion proportional to the Gd content, while SEM analysis reveals morphology evolving from flattened rectangles to cubes with increasing substitution. Density functional theory calculations reveal complex bandgap evolution (2.30–2.31 eV) with nonlinear electronic structure changes upon Gd doping, attributed to varying magnetic ordering configurations in the G-type antiferromagnetic structure, validated by UV–visible reflectivity measurements. Magnetic characterization shows enhanced saturation magnetization from 1.87 emu/g (x = 0.2) to 3.53 emu/g (x = 1.0) due to Gd³⁺magnetic contributions while preserving canted antiferromagnetism. Notably, Y<inf>0.4</inf>Gd<inf>0.6</inf>FeO<inf>3</inf>exhibits excellent ferroelectric performance with remnant polarization of 6.23 μC/cm²at 100 kV/cm. These findings demonstrate effective property tuning through Gd doping, where the enhanced magnetization and tunable bandgap advance orthoferrites for magnetic memory applications and the observed ferroelectric properties enable multiferroic sensing capabilities.

DOI： 10.1021/acs.jpcc.5c03950

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Materials Chemistry A  

Theoretical design and experimental proof of photocatalytic performance of eosin Y (EY) on anatase TiO<inf>2</inf> with a pyridine linker were obtained for increasing the photobiocatalytic activity of water splitting using visible light. Comparative studies on the hybrid interface of anatase and EY with carboxyl and pyridine anchors were performed by using density functional theory (DFT), time-dependent density functional theory (TD-DFT) calculations and experimental photoreduction of methyl viologen (MV). The geometries, binding interactions between dyes and anatase, electronic structures and electron transfer as well as the effect of isomers (ortho, meta, and para) on the dye/anatase systems were investigated. Theoretical results indicated that EY with carboxyl and pyridine anchors had visible absorption and electron transfer from the dye to the anatase titania. Compared to carboxyl-para, which had the best optical performance among carboxyl groups, the adsorption strength of pyridine-ortho was close to that of carboxyl-para, while the oscillator strength increased significantly, which was more than 10 times higher than that of carboxyl-para. Corresponding with the theoretical estimation, EY pyridine linked TiO<inf>2</inf> is active to MV reduction under visible light irradiation by fast charge transfer, in particular, pyridine-ortho and para. Furthermore, high stability is also achieved for pyridine-para. An apparent quantum yield higher than 2.00% and 0.67% under 520 nm light was experimentally achieved in biocatalytic H<inf>2</inf> and NH<inf>3</inf> formation, respectively, for EY pyridine linked TiO<inf>2</inf>, which was correctly predicted by the DFT calculations.

DOI： 10.1039/d5ta05712d

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Publisher：Engineering Failure Analysis  

Hydrogen pipelines offer an efficient transportation method, but they pose significant safety challenges due to hydrogen embrittlement. The effect of hydrogen pressure on the fracture toughness of pipelines requires further investigation. This study examines the fracture toughness of pipeline steel exposed to high-purity hydrogen gas at various pressures. The experimental results indicate that the fracture toughness decreases progressively with increasing hydrogen pressure, following a trend resembling logarithmic or power-law behavior. Microscopic analysis reveals a shift in the fracture mode from ductile dimple-dominated failure to brittle fracture as the pressure increases from 0 to 12 MPa. Two empirical relationships are evaluated: the theoretically derived Kim model and its X80 calibrated version. The calibration of the Kim model has reduced the relative error of the model for X80 fracture toughness under varying hydrogen pressure conditions. Additionally, an empirical relationship that provides a lower bound of fracture toughness based on the measurements in this study has been developed. And the model is shown to also bound the data in the literature for X80 in gaseous hydrogen at pressure up to 12 MPa at room temperature. These findings provide valuable insights into assessing the structural integrity of hydrogen pipelines.

DOI： 10.1016/j.engfailanal.2025.109917

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Authorship：Corresponding author   Publishing type：Research paper (scientific journal)   Publisher：Engineering Failure Analysis  

The use of underground hydrogen storage enables large-scale and cost-effective storage of hydrogen. However, the presence of carbon dioxide (CO<inf>2</inf>) in underground hydrogen reservoirs can influence the interaction between hydrogen and the tubing materials. This study investigated the effects of varying CO<inf>2</inf> concentrations on the hydrogen-assisted cracking in P110 steel by a combined study of fatigue crack growth rate (FCGR) experiments and density functional theory (DFT) calculations. Experimental results indicated that the presence of CO<inf>2</inf> accelerates the FCGR compared to pure hydrogen. As the concentration of CO<inf>2</inf> increased, the FCGR initially rose and then declined, peaking in 0.008 MPa CO<inf>2</inf> + 7.992 MPa H<inf>2</inf> (0.1 vol% CO<inf>2</inf> + H<inf>2</inf>). Additionally, the presence of CO<inf>2</inf> promoted the emergence of the critical stress intensity factor for hydrogen-accelerated fatigue crack growth, bringing the turning point forward from 27 MPa·m^1/2 to approximately 17 MPa·m^1/2. DFT calculations elucidated that the activation energy for hydrogen dissolution first decreased and then increased as the partial pressure of CO<inf>2</inf> in the hydrogen environment rose. This suggested that the ease of hydrogen permeation into the steel surface initially decreased and then increased, in alignment with the experimental findings.

DOI： 10.1016/j.engfailanal.2025.109808

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Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：International Journal of Hydrogen Energy  

This study investigates the mechanical performance of X80 pipeline steel and its welded joints in hydrogen-blended natural gas environments at 10 MPa. Slow strain rate tensile, low-cycle fatigue, fatigue crack growth, and fracture toughness tests are conducted on base metal, weld metal, and heat-affected zone. Hydrogen addition reduces ductility, increases fatigue crack growth rate by nearly one order of magnitude, and lowers fracture toughness by up to 51.9 %. The predicted fatigue life decreases by as much as 94.5 % with 30 vol% hydrogen blending. Fatigue crack growth rate and fracture toughness tests indicated that the base metal exhibited the highest hydrogen embrittlement sensitivity, followed by the weld metal and the heat-affected zone. However, all specimens maintain fatigue lives exceeding one million cycles under typical pressure fluctuations. These results suggest that hydrogen transport through existing natural gas pipelines may be feasible when considering the pipe material alone. The findings provide essential data for evaluating the hydrogen compatibility of X80 steel in realistic gas mixtures and contribute to the development of safe hydrogen blending strategies.

DOI： 10.1016/j.ijhydene.2025.150815

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

In this study, we explored the effect of dry hydrogen sulfide (H<inf>2</inf>S) on the hydrogen embrittlement sensitivity of X80 pipeline steel through several different tests: fatigue crack growth tests, fracture toughness tests, and density functional theory (DFT) calculations. The results showed that the addition of 3.952 ppm H<inf>2</inf>S into 12 MPa hydrogen (H<inf>2</inf>) slightly enhanced the hydrogen-induced degradation of the fatigue and fracture properties of the X80 steel. The degradation of the material became severe when the content of H<inf>2</inf>S increased to 19.76 ppm. Fracture surface observations indicate that H<inf>2</inf>S does not significantly change the fracture mode of the specimen compared to that in hydrogen gas. DFT calculations qualitatively reveal that H<inf>2</inf>S enhances the hydrogen adsorption on iron surface and the dissolution rate into the subsurface. This process promotes the accumulation of hydrogen in the material, thereby increasing the hydrogen embrittlement of the pipeline steel.

DOI： 10.1016/j.corsci.2025.113056

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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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Publishing type：Research paper (scientific journal)   Publisher：Zhejiang University Press  

DOI： 10.1631/jzus.a2300620

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Other Link： https://link.springer.com/article/10.1631/jzus.A2300620/fulltext.html

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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Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>Hydrogen-assisted fatigue crack growth (HAFCG) is a critical concern for steels used in hydrogen transport and storage systems. This study investigated the effects of CO₂ pressure and concentration on HAFCG in GB20 low-carbon steel and P110 casing steel. Fatigue crack growth tests were conducted under hydrogen/CO₂ mixtures. In GB20 steel, CO₂ markedly accelerated crack growth at 0.4 MPa, whereas the promoting effect was reduced at 10 MPa. In P110 steel tested at 8 MPa, the fatigue crack growth rate peaked at 0.1vol% CO₂ and decreased at higher concentrations up to 1vol%. First-principles calculations revealed that the activation energy for hydrogen dissolution decreased and then increased with the CO₂/H₂ surface coverage ratio, explaining the observed promotion-to-attenuation trend. These findings indicate that CO₂ plays a dual role in hydrogen-assisted fatigue, governed by both pressure and concentration. At low pressure the promoting effect dominates, while at higher pressure or concentration its impact diminishes, suggesting the existence of a critical turning point in CO₂–H₂ interactions that requires further investigation.</p>

DOI： 10.1299/jsmemm.2025.os1910

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

<p>This study examines the creep behavior of Crofer 22H ferritic stainless steel in hydrogen and argon atmospheres to clarify the role of hydrogen in high-temperature creep deformation and creep fracture mechanisms. Crofer 22H is a promising candidate material for solid oxide fuel cell (SOFC) interconnects, and its long-term reliability under hydrogen exposure is therefore of particular importance. Creep tests were performed at 550 °C and 600 °C using a specimen having rectangular cross section with 5 mm × 5 mm in size and a gauge length of 17 mm. The results revealed that the creep life was considerably shorter in hydrogen compared with argon under equivalent stress conditions, indicating that hydrogen accelerates the progression of creep damage. Fractographic observations showed ductile fracture with dimples in both atmospheres, and no remarkable difference in the dimple morphology was detected. However, dimples tend to appear shallower and more uniform in hydrogen, suggesting that numerous fine voids coalesced before individual dimples could fully grow.</p>

DOI： 10.1299/jsmemm.2025.os1903

CiNii Research

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：Corrosion Science  

This study highlights the significant role of total gas pressure in enhancing hydrogen degradation in hydrogen/inert gas mixtures. Tests were performed to measure the fatigue crack growth rate (FCGR) of X80 and GB20# pipeline steels in pure hydrogen and hydrogen/nitrogen blends. Findings showed that FCGR increased in the blend with elevated total gas pressure relative to pure hydrogen, despite an equivalent hydrogen partial pressure between the two environments. First-principles molecular dynamics (FPMD) calculations revealed that the increased number of nitrogen molecules within the Fe-H<inf>2</inf>-N<inf>2</inf> systems promoted the movement velocity of hydrogen and premature dissociation of hydrogen.

DOI： 10.1016/j.corsci.2024.112466

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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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Publishing type：Research paper (scientific journal)  

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

Event date： 2020.11

Language：English   Presentation type：Oral presentation (invited, special)  

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Presentation type：Oral presentation (invited, special)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (invited, special)  

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Presentation type：Oral presentation (general)  

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Presentation type：Oral presentation (general)  

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