International Journal of Hydrogen Energy最新文献

{"title":"Evaluation of reaction conditions in the dry reforming process using a Ni/MCM-41 catalyst for syngas production","authors":"Guilherme Emanuel de Queiros Souza ,&nbsp;Rodolfo de Andrade Schaffner ,&nbsp;Cleuciane Tillvitz do Nascimento ,&nbsp;Carla Maria Beraldi Gomes ,&nbsp;Lígia Gomes Oliveira ,&nbsp;Daiane Letícia Cerutti ,&nbsp;Alessandra Freddo ,&nbsp;Daiana Gotardo Martinez ,&nbsp;Helton José Alves","doi":"10.1016/j.ijhydene.2025.150503","DOIUrl":"10.1016/j.ijhydene.2025.150503","url":null,"abstract":"<div><div>The dry reforming of biogas offers a sustainable route for syngas production. This study evaluates a nickel catalyst supported on Si-MCM-41 for dry reforming, with a focus on optimizing reaction parameters such as, catalyst size and mass, pressure, and space velocity. Catalyst stability and resistance to H₂S poisoning were also assessed. The catalyst Ni/MCM-41 was characterized before and after reaction using TGA, XRD, N₂ physisorption, SEM, TEM, FTIR, and TPR. The best performance was achieved with 3 g of catalyst (500–710 μm), under atmospheric pressure and a space velocity of 7.20 L h⁻¹ gcat⁻¹, reaching CH₄ and CO₂ conversions of 99.14 % and 97.48 %, and H₂ and CO selectivity near 49 %. The catalyst remained stable for 50 h and tolerated H₂S concentrations up to 10 ppm. This study demonstrates the potential of Ni/MCM-41 as a stable and sulfur-tolerant catalyst for dry reforming, highlighting its suitability for efficient biogas upgrading.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150503"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Donor-acceptor engineering of NiPc-based covalent organic frameworks for boosting oxygen reduction and hydrogen evolution reactions","authors":"Ruichen Li ,&nbsp;Tian Yang ,&nbsp;Jingjing Zhang ,&nbsp;Jia Wang ,&nbsp;Ge Wang ,&nbsp;Shujun Chao","doi":"10.1016/j.ijhydene.2025.150521","DOIUrl":"10.1016/j.ijhydene.2025.150521","url":null,"abstract":"<div><div>Covalent organic frameworks (COFs), particularly imine-linked COFs, have emerged as viable electrocatalytic materials to promote oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). However, a slow intramolecular charge transfer significantly limits their electrocatalytic activity. One effective strategy to overcome this drawback involves the introduction of donor-acceptor (D-A) structural units to the imine-linked COFs. Herein, with a donor-acceptor engineering strategy, three novel imine-linked COFs with D-A structural units that serve as efficient ORR/HER bifunctional electrocatalysts have been synthesized using 2,5-thiophenedicarboxaldehyde (TDA), thieno[3,2-<em>b</em>]thiophene-2,5-dicarboxaldehyde (TT) and benzo[1,2-<em>b</em>:3,4-<em>b</em>':5,6-<em>b</em>'']trithiophene-2,5,8-tricarbaldehyde (BTT) as electron donors, and 2,9,16,23-tetraaminophthalocyanine nickel (II) (NiPc) as an electron acceptor (denoted as TDA-NiPc-COF, TT-NiPc-COF and BTT-NiPc-COF). When compared with TDA-NiPc-COF and BTT-NiPc-COF, TT-NiPc-COF exhibits the higher ORR/HER activity thanks to its larger specific surface area, more abundant catalytic sites and stronger intrinsic charge transfer ability. Theoretical calculations have revealed that TT-NiPc-COF has the smallest HOMO-LUMO energy gap and lowest Gibbs free energy values for intermediates on the Ni–N and thiophene-S sites, indicating the fastest charge transfer ability and the most positive catalytic ability for ORR/HER. In addition, a negatively shifted d-band center energy provided by TT-NiPc-COF indicates an optimized adsorption strength of ORR-correlated intermediates, resulting in substantial improvement in ORR activity. This study provides a new insight into the rational design of novel imine-linked COFs with D-A structural units for application in the electrocatalytic field.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150521"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655160","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of free radical degradation mechanisms of membrane electrode assembly based on ultraviolet/hydrogen peroxide advanced oxidation process","authors":"Zhongju Wang ,&nbsp;Tengda Guo ,&nbsp;Hui Liu ,&nbsp;Zhonghui Wang ,&nbsp;Jianbo Zhang ,&nbsp;Qiang Liu ,&nbsp;Zixi Wang","doi":"10.1016/j.ijhydene.2025.150362","DOIUrl":"10.1016/j.ijhydene.2025.150362","url":null,"abstract":"<div><div>The main challenges in the commercialization of proton exchange membrane fuel cells (PEMFCs) are their high cost and poor durability; one of the key factors limiting their lifetime is the attack of free radicals (•OH) on membrane electrode assemblies. In this study, a quantitative free-radical aging device is built based on an ultraviolet (UV)/hydrogen peroxide (H₂O₂) Advanced Oxidation Process, which precisely regulates the generation rate of hydroxyl radicals. The results show that free-radical attack leads to polymer backbone and side-chain breakage, as well as the loss of sulfonic acid groups. The tensile strength and water absorption properties of the catalyst-coated membrane (CCM) are significantly reduced, while the gas permeability remains stable. The catalyst layer (CL) thickness decreases, and the mass loss rate increased. The hydrophobicity of the microporous layer (MPL) surface decreases continuously with the free-radical attack, the first 10 h, rapid defluorination and initial oxidation lead to a decrease in hydrophobicity. From 10 to 40 h, the defluorination rate slows, but oxidation continues, further diminishing the hydrophobicity. This study provides an in-depth understanding of the aging mechanisms of free radicals in fuel cells and offers an important theoretical basis for designing durable membrane electrode assembly (MEA) materials.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150362"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Promoting directional reconstruction of double perovskites for efficient water splitting","authors":"Yu Li ,&nbsp;Wanxia Huang ,&nbsp;Gao Chen ,&nbsp;Yongxin Li ,&nbsp;Liangshuang Fei ,&nbsp;Yuxing Gu ,&nbsp;Ran Ran ,&nbsp;Wei Zhou","doi":"10.1016/j.ijhydene.2025.150527","DOIUrl":"10.1016/j.ijhydene.2025.150527","url":null,"abstract":"<div><div>Double perovskite oxides are promising electrocatalysts for water electrolysis due to their tunable structure and ordered ion arrangement. However, while in-situ surface reconstruction of perovskites enhances oxygen evolution reaction (OER) activity, this process is inherently uncontrollable, as structural instability drives irreversible phase transitions and active metal dissolution, ultimately degrading both activity and stability. Herein, we developed an Fe³⁺-induced directional reconstruction strategy that transforms double perovskite Sr₂NiMoO₆ into a heterostructure consisting of crystalline SrMoO₄ and amorphous NiFeO_xH_y. In-situ analyses reveal that this structural reconstruction simultaneously optimizes OH⁻ adsorption at NiFe dual-active sites and activates more lattice oxygen contributions to the reaction. Moreover, dynamically dissolved Mo species during the OER serve as electronic modulators to facilitate rapid reconfiguration of Ni ions while suppressing detrimental over-oxidation and dissolution. This strategy can be extended to optimize other double/triple perovskite oxides, where directional reconstruction and enhanced OER activity/stability are obtained.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150527"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of hydrogen on nickel extraction from low-grade ultramafic nickel sulfide concentrate","authors":"Fanmao Wang ,&nbsp;Sam Marcuson ,&nbsp;Reda Elsawi ,&nbsp;Lucy Liu ,&nbsp;Mansoor Barati","doi":"10.1016/j.ijhydene.2025.150506","DOIUrl":"10.1016/j.ijhydene.2025.150506","url":null,"abstract":"<div><div>Low-grade ultramafic nickel sulfide ores represent an important but underutilized resource for nickel production. However, their high MgO content poses significant challenges to conventional smelting processes, limiting their economic and environmental viability. The authors proposed a solid-state nickel extraction method, employing metallic iron as a nickel extractant under inert or H₂–Ar atmospheres, to avoid high-temperature smelting and enable direct extraction of nickel as ferronickel. Although hydrogen was present in the atmosphere, the authors observed the loss of iron into iron-magnesium oxides and silicates. The aim of the current work is to understand the mechanism of iron oxidation and the effect of atmosphere on it. It was found that hydrogen helps create a low oxygen potential environment around the sample (logP_O2 = −22 to −17 at 750–920 °C), but oxygen-buffering minerals in the ultramafic concentrate create local oxidizing conditions, leading to the oxidation of iron. Kinetic analysis reveals that hydrogen reduction of iron oxide in the complex compounds with MgO and sulfides is hindered by high activation energy barriers (E_a = 240 kJ/mol). These findings highlight critical factors affecting the efficiency of hydrogen-based reductio in complex mineral matrices.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150506"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study on hydrogen recovery performance of a novel industrial scale hydride-based flow-through hydrogen purification reactor with distributed gas inlet tubes","authors":"Ruiqing Li,&nbsp;Guangze Wan,&nbsp;Leilei Guo,&nbsp;Fusheng Yang,&nbsp;Zhen Wu,&nbsp;Zaoxiao Zhang","doi":"10.1016/j.ijhydene.2025.150496","DOIUrl":"10.1016/j.ijhydene.2025.150496","url":null,"abstract":"<div><div>In this study, an industrial-scale, flow-through metal hydride hydrogen purification (MHHP) reactor with distributed gas inlet tubes loaded with 160 kg of LaNi₄.₃Al₀.₇ material was designed. Numerical simulations were employed to analyze the impact of reactor structure parameters, such as bed thickness and gas inlet tube length. Further, we investigated how operational parameters, including heat transfer fluid temperature, hydrogen partial pressure, and raw gas composition, influence the absorption efficiency of the reactor. Moreover, an annular finned MHHP reactor was designed, which increased the hydrogen absorption efficiency from 70 % to 77.7 % under low pressure (0.67 MPa). This research contributes to the development of high-performance industrial scale MHHP reactor, provides valuable insights into the application of large MHHP reactors in the recovery of industrial by-product hydrogen.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150496"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen production from plastic waste pyrolysis syngas: A review on progresses and challenges","authors":"M.B. Uddin,&nbsp;M.G. Rasul,&nbsp;Ashfaque Ahmed Chowdhury,&nbsp;N.M.S. Hassan","doi":"10.1016/j.ijhydene.2025.150512","DOIUrl":"10.1016/j.ijhydene.2025.150512","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Globally, 380 million tons of plastic are produced annually, and more than 75 % of these plastics are rejected as waste in the environment. The increasing accumulation of plastic waste poses significant environmental, and health risks and urges the need for sustainable waste management strategies. One promising solution is the conversion of plastic waste into valuable energy products (oil, char, and syngas) through thermochemical processes, such as pyrolysis/gasification. This review focuses on hydrogen production from syngas derived from the pyrolysis of plastic waste. PET and HDPE emerge as highly effective feedstocks, producing gaseous yields of up to 77 % and 66 %, respectively, during pyrolysis. Researchers favour pyrolysis because of its ability to yield syngas from 35 % to 40 % from plastic waste, depending on the type of pyrolysis process used. This review evaluates the impact of key pyrolysis process parameters (temperature, pressure, residence time, heating rate, catalyst, and feedstock composition) on hydrogen yield and its quality. Pyrolysis, particularly using different types of catalysts, increases hydrogen output to as high as 219 mmol/g to 730.6 mmol/g. Advances on palladium-based membranes have been discussed for their role in separating hydrogen from syngas efficiently, achieving 99.99 % purity. Among palladium-based membranes, performance of PdAg is reviewed in detail as it shows good effectiveness against impurities, carbon dioxides (C &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, carbon monoxide (CO), methane (C &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, etc. and efficiency against poisoning (sulphur and Chlorine) that reduce the membrane thickness, durability, quality, stability and selectivity. The highest permeability of palladium silver (PdAg) membrane was found 3.2 × &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mn&gt;10&lt;/mn&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;8&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; mol. &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msup&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;msup&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;mo&gt;.&lt;/mo&gt;&lt;msup&gt;&lt;mtext&gt;pa&lt;/mtext&gt;&lt;mrow&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0.5&lt;/mn&gt;&lt;/mrow&gt;&lt;/msup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; at 450 °C and the lowest thickness was found 0.8 μm. Plastic waste pyrolysis produces significantly lower C &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (1–3 kg C&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;O&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;/kg &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) emissions compared to traditional methods such as landfilling, incineration and recycling. The review concludes with a roadmap for future research directions aimed at optimising hydrogen separation from plastic waste syngas to develop cost-effective, sustainable solutions for plastic waste management and clean energy production, thereby contributing to a cleaner environment and sustainable energy future.&lt;","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150512"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synergistic effects of SO42− /PO43− modification and Fe-loading on NH3-SCR activity in surface-engineered rare earth concentrate catalysts","authors":"Dongming Pan ,&nbsp;Yuchen Liu ,&nbsp;Jin xiao Bao ,&nbsp;Ran Zhao ,&nbsp;Zhijia Mao","doi":"10.1016/j.ijhydene.2025.150351","DOIUrl":"10.1016/j.ijhydene.2025.150351","url":null,"abstract":"<div><div>Bayan Obo rare earth concentrate (REC), naturally rich in Ce and low in transition metals, exhibits high stability and poison resistance, making it promising for NH₃-SCR. The REC was first modified with H₂SO₄ (S) or H₃PO₄ (P). Optimizing acid concentration revealed that 6 mol/L H₂SO₄ and 4 mol/L H₃PO₄ yielded catalysts with the best SCR activity. To broaden the temperature window and enhance activity, acid-treated REC(REC-S/P) was further modified with Fe via impregnation, creating Fe₂O₃/REC-(S/P) catalysts. Studies on varying Fe/Ce ratios showed an optimal loading (Fe/Ce = 0.8) significantly expanded the operating temperature range and improved N₂ selectivity. These catalysts achieved &gt;90 % NO_<em>x</em> conversion between 325 and 375 °C. Iron loading critically enhanced SCR activity by improving redox properties and increasing available acidic sites. In-situ IR studies explored adsorption (NH₃, NO, O₂) and reaction pathways. Adsorbed NO was oxidized by surface Fe³⁺ to form –NO₂^- and –NO₃^- species, primarily via the Langmuir-Hinshelwood (L-H) mechanism. At higher temperatures, adsorbed NH₃ species activated by Fe³⁺ formed amide (NH₂). Crucially, this NH₂ on Fe₂O₃/REC-(S/P) could be oxidized to N₂O, predominantly through the Eley-Rideal (E-R) mechanism.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150351"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and simulation study on the sealing performance of rubber O-rings exposed to hydrogen conditions","authors":"Jianlu Zhu ,&nbsp;Jie Zhang ,&nbsp;Yuchen Lu ,&nbsp;Yao Duan ,&nbsp;Yuxing Li ,&nbsp;Cuiwei Liu ,&nbsp;Jiang Zhao ,&nbsp;Lei He ,&nbsp;Xin Liu","doi":"10.1016/j.ijhydene.2025.150239","DOIUrl":"10.1016/j.ijhydene.2025.150239","url":null,"abstract":"<div><div>As the key link of pure hydrogen and hydrogen-doped pipeline system, rubber O-ring sealing element is of great significance for the safe and efficient transportation of pipeline. The variation law of leakage rate of rubber O-ring under various factors such as preload, sealing ring size, hydrogen pressure and hydrogen blending ratio was explored from a macro perspective through experiments, and the mechanical properties of rubber materials under hydrogen permeation conditions were further studied from a micro perspective through simulation. The results show that: (1): Under the condition of hydrogen permeation, with the increase of preload torque, the leakage rate of the sealing system shows a trend of decreasing first and then increasing. When the diameter of the O-ring is constant, the leakage rate tends to increase linearly with the increase of the inner diameter, and the sealing performance is weak. With the increase of hydrogen pressure, the gas leakage rate decreases exponentially. The hydrogen blending ratio is negatively correlated with the leakage rate, and increasing the hydrogen blending ratio will promote the sealing performance. (2) Under the condition of hydrogen permeation, the contact stress of the rubber O-ring increases linearly with the increase of hydrogen pressure. Substituting it into the leakage rate formula, it is found that the leakage rate decreases, which is consistent with the experimental conclusion, but the pressure rise will also increase the Mises stress, and cause the volume of the O-ring outside the extrusion groove to increase, accelerating the sealing failure. The increase of hydrogen blending ratio will increase the contact stress and reduce the Mises stress, but the effect is not obvious. (3) A theoretical formula of hydrogen leakage rate with multiple independent variables and single dependent variable is established. Suggestions on the selection of flange seals and the application of process operation parameters in hydrogen environment are put forward, which provides theoretical support for the safe transportation of pure hydrogen or hydrogen-doped natural gas pipelines.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150239"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrogen vacancies enriched g-C3N4 nanosheets for photocatalytic CO2 reduction","authors":"Donghui Hu,&nbsp;Shurong Li,&nbsp;Yulu Chen,&nbsp;Yan Shen,&nbsp;Xiangyu Liao,&nbsp;Xu Zhou,&nbsp;Haoran Xu,&nbsp;Yang Tan,&nbsp;Junbo Zhong","doi":"10.1016/j.ijhydene.2025.150571","DOIUrl":"10.1016/j.ijhydene.2025.150571","url":null,"abstract":"<div><div>Photocatalytic carbon dioxide (CO₂) reduction is an effective pathway to balance CO₂ production and consumption while achieving carbon neutrality. Graphitic carbon nitride (g-C₃N₄) is a promising non-metal semiconductor for photocatalytic CO₂ reduction. Nonetheless, the primary reason limiting the high CO₂ reduction performance is still the inadequate charges separation of g-C₃N₄. Herein, g-C₃N₄ with enriched nitrogen vacancies (NVs) was synthesized at room temperature by oxalic acid treatment. As electron traps and adsorption sites, NVs improve the separation efficiency of electron-hole pairs and increase CO₂ adsorption capacity. As a result, the photocatalytic CO₂ reduction activity of g-C₃N₄ can be improved with optimized 11CN having an activity 2.8 times of that of g-C₃N₄.</div></div>","PeriodicalId":337,"journal":{"name":"International Journal of Hydrogen Energy","volume":"158 ","pages":"Article 150571"},"PeriodicalIF":8.1,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144655162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}