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Effect of N-doping and biaxial compressive strain on H2 adsorption of 2D holey graphyne monolayer via first-principles study

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2025年 115卷 186-197页

作者： Beniwal, Preeti Chakraborty, Brahmananda Kumar, T. J. Dhilip Indian Inst Technol Ropar Dept Chem Rupnagar 140001 India Bhabha Atom Res Ctr High Pressure & Synchrotron Radiat Phys Div Mumbai 400085 India Homi Bhabha Natl Inst Mumbai 400094 India

Developing advanced materials plays an essential role in improving the efficiency and stability of hydrogen storage systems. We have explored the hydrogen storage properties of a recently synthesized holey graphyne (HGY) monolayer, considering the impacts of nitrogen doping followed by biaxial compressive strain. H2 adsorption energy on the pristine HGY is too low, i.e., -0.157 eV fora single H2 adsorption, to comply with the standards for hydrogen storage. N-doping leads to improved interaction with H2, thereby the increased adsorption energy. Doping induces substantial changes in the electronic properties, as with 1 N (4.16 at.%) doping within a unit cell comprising 24 C atoms, the semiconducting nature of HGY transforms to metallic and with 6 N (25 at.%) doping, it reverts to semiconductor state featuring a reduced band gap of 0.40 eV. 3NHGY (12.5 at.% doping) is taken as the optimum case with symmetric doping and metallic nature. It shows a comparatively higher adsorption energy fora single H2 molecule (-0.175 eV). Afterward, we explored the adsorption properties of 3NHGY subjected to biaxial compressive strain. The application of compressive strain induces an increase in the electronic density in the bonds, thereby facilitating a stronger adsorption of H2 molecules and thus elevating the adsorption energy. Under 4% strain, 3NHGY can adsorb 10 H2 molecules with the adsorption energy within -0.191 to -0.338 eV, reflecting a gravimetric density of 6.42 wt%. Ab initio molecular dynamics simulation affirms the structural and thermal stability of the unstrained and strained 3NHGY monolayers. From the findings, we can infer that this study emphasizes the quest to enhance the hydrogen storage efficiency of 2D materials.

关键词： DFT aimd simulation Biaxial strain Gravimetric density H2 adsorption

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Modulation of H2 adsorption in C9N4 monolayer via biaxial strain for hydrogen storage

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APPLIED SURFACE SCIENCE 2025年 690卷

作者： Beniwal, Preeti Kumar, T. J. Dhilip Indian Inst Technol Ropar Dept Chem Rupnagar 140001 India

Two-dimensional (2D) carbon nitride materials hold significant potential as hydrogen storage mediums owing to remarkable chemical stability and large surface area. Prompted by this exploration, leveraging first-principles computations, the hydrogen storage possibility of an innovative C9N4 monolayer is studied systematically. H2 adsorption energy on pristine C9N4 lies below the threshold value of -0.20 eV due to weak van der Waals interactions. To optimize the adsorption interaction between the H2 and monolayer, we explored the hydrogen storage possibilities of a C9N4 monolayer when subjected to biaxial strain. The introduction of compressive strain enhanced the reactivity of the monolayer, subsequently improving its adsorption energies. Inducing 4% biaxial compressive strain on C9N4, i.e. in 4%epsilon-C9N4, the adsorption energy successfully enhanced and the system adsorbs a single H2 molecule with -0.32 eV. 4%epsilon-C9N4 monolayer effectively adsorb 8 H2 molecules, demonstrating the adsorption energy spanning from -0.20 to -0.32 eV, thereby achieving a storage capacity of 8.95 wt%. This work present an effective approach for optimizing the storage attributes of 2D carbon nitrides, serving as an impetus toward the ongoing improvement of advanced hydrogen storage materials.

关键词： Biaxial strain Hydrogen storage capacity H2 adsorption Polarization aimd simulation

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Investigation of structural, phonon, thermodynamic, electronic, and mechanical properties of non-toxic XZnH3 (X = Li, Na, K) perovskites for solid-state hydrogen storage: A DFT and aimd approach

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JOURNAL OF ENERGY STORAGE 2025年 112卷

作者： Archi, M. Bajjou, O. Rahmani, K. Elhadadi, B. Sultan Moulay Slimane Univ Polydisciplinary Fac Res Lab Phys & Sci Engineers LRPSI Beni Mellal Morocco Sultan Moulay Slimane Univ Lab Engn Chem & Phys Matter LICPM Beni Mellal Morocco Univ South Afr UNISA Coll Grad Studies U2ACN2 Pretoria South Africa Mohammed V Univ Rabat Fac Sci ENS Rabat LPHE MS Rabat Morocco

Due to its abundance on earth, clean, and non-toxicity, hydrogen is one of the best choices to replace fossil fuels. However, finding efficient storage methods remains a significant challenge. Perovskite hydrides have gained attention as potential solid-state storage materials due to their safety and higher density. In this paper, we conducted a comprehensive investigation into the stability, electronic, mechanical, and thermodynamic properties of the non-toxic XZnH3 (where X = Li, Na, K) compounds as potential candidates for solid-state hydrogen storage using Density functional theory. The structural characteristics and XRD patterns demonstrate that these materials exhibit a cubic phase with KZnH3 has the higher volume due it is higher lattice constant of 3.83 & Aring;, compared to LiZnH3 (3.58 & Aring;) and NaZnH3 (3.68 & Aring;). The phonon dispersion curves revealed the absence of negative frequencies, confirming the dynamical stability of these materials. Additionally, the formation energy results validated their synthesizability and thermodynamic stability, and the elastic constants (Cij) satisfied the Born criteria, ensuring that these materials are mechanically stable. Moreover, the aimd simulations were performed to investigate the thermal stability of these compounds. Analysis of the electronic band structure and density of states verified the metallic nature of all XZnH3 perovskites, highlighting their excellent electrical conductivity which enhances the charge transfer, and improves the adsorption and desorption of hydrogen atoms. In addition, the thermodynamic properties including free energy, enthalpy, zero-point energy, entropy, and specific heat capacity were analyzed at different temperatures. The mechanical properties of XZnH3 (X = Li, Na, K) hydrides, including high bulk modulus, Debye temperature, and melting point, suggest their structural resilience and significant resistance to deformation. Their favorable B/G ratios and Cauchy pressures indic

关键词： Hydride perovskites First-principles study Hydrogen storage Desorption temperature aimd simulation Gravimetric capacity Stability properties

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Reactivity of Carbonyl-Containing Solid Polymer Electrolytes in Lithium-Metal Batteries from First-Principles Molecular Dynamics

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ACS APPLIED POLYMER MATERIALS 2025年第6期7卷 3636-3646页

作者： Wu, Liang-Ting Mindemark, Jonas Brandell, Daniel Jiang, Jyh-Chiang Natl Taiwan Univ Sci & Technol Dept Chem Engn Taipei 106 Taiwan Natl Taiwan Univ Sci & Technol Sustainable Electrochem Energy Dev Ctr SEED Ctr Taipei 106 Taiwan Uppsala Univ Dept Chem Angstrom Lab S-75121 Uppsala Sweden

Solid polymer electrolytes (SPEs) are promising candidates for all-solid-state Li-metal batteries (ASSLMBs) due to their high safety and excellent mechanical flexibility. However, the widely used polyethers suffer from low ionic conductivity at ambient temperature and unstable electrode-electrolyte interfaces. In this work, we systematically investigate the reactivities with metallic lithium of three carbonyl-containing polymer-based SPE hosts-a polyketone (POHM), a polyester (PCL), and a polycarbonate (PTeMC)-as potential alternatives to polyethers by means of DFT calculations and aimd simulations. Our redox potential and frontier orbital analyses indicate that introducing alkoxy oxygens connected to carbonyl groups enhances the electrochemical stability of polyester and polycarbonate, but also increases their reactivity on the Li anode surface. In particular, PTeMC shows higher electron uptake and a lower conduction band when interacting with surface Li. This increased reactivity, however, may also promote the formation of a stable solid electrolyte interphase (SEI), preventing further reduction of the electrolyte. We further summarize the possible decomposition mechanisms of the SPE polymer host and predict the resulting SEI components. The simulations revealed that POHM predominantly undergoes alpha-dehydrogenation and nucleophilic addition-elimination reactions, while PCL exhibits Ccarbonyl-Oalkoxy bond cleavage, producing both saturated and unsaturated lithium alkoxides. In the case of PTeMC, breaking two Ccarbonyl-Oalkoxy bonds can generate two saturated lithium alkoxides and a Li x CO species, or it can produce a RCO3Li species and unsaturated hydrocarbons via a Calkoxy-Oalkoxy bond cleavage;these pathways are kinetically favorable and unfavorable, respectively. This work underscores the influence of alkoxy oxygens in carbonyl-containing polymers and provides computational insights for guiding polymer electrolyte design.

关键词： DFT calculation aimd simulation solid polymerelectrolytes Li-metal batteries reactivity carbonyl-containing polymer

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Insights from Ab Initio Molecular Dynamics on the Interface Reaction between Electrolyte and Li2MnO3 Cathode during the Charging Process

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ACS APPLIED MATERIALS & INTERFACES 2024年第34期16卷 44979-44987页

作者： Yan, Xiaotong Huang, Weijie Zhu, Chunwei Zhao, Yu-Jun South China Univ Technol Dept Phys Guangzhou 510641 Peoples R China South China Univ Technol Key Lab Adv Energy Storage Mat Guangdong Prov Guangzhou 510641 Peoples R China

The complex interface reactions are crucial to the performance of the Li2MnO3 cathode material. Here, the interface reactions between the liquid electrolyte and the typical surfaces of Li2MnO3 during the charging process are systematically investigated by ab initio molecular dynamics (aimd) simulation and first-principles calculation. The results indicate that these interface reactions lead to the formation of hydroxide radicals, oxygen, carbon dioxide, carbonate radicals, and other products, which are consistent with the experimental findings. These processes primarily result from the conversion of the stable closed-shell O2- into reactive oxygen ions by electron loss. All surfaces exhibit some degree of layered- and spinel-like phase transitions during the aimd simulations, consistent with the experiment. This is mainly attributed to the decrease in the Mn-O bond strength and the increase in the Li/O ion vacancy concentration. This study offers valuable theoretical insights into the interface reaction between lithium-rich cathode materials and liquid electrolytes.

关键词： aimd simulation liquid electrolyte Li2MnO3 cathode material interface reaction charging process

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Influence of hydrogen volume/specimen surface area ratio on hydrogen embrittlement sensitivity of X52 pipeline steel

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INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING 2024年 209卷

作者： Peng, Shiyao Zhang, Yan-Hui Li, Ba Wang, Bing Chai, Chong Jia, Shujun Liu, Qingyou Mi, Zhishan Natl Oil & Gas Pipeline Network Corp PipeChina Sci & Technol Inst 51 Jinguang Ave Langfang Peoples R China Cent Iron & Steel Res Inst Co Ltd Beijing 100081 Peoples R China China Iron & Steel Res Inst Grp Mat Digital R&D Ctr Beijing 100081 Peoples R China

In the transition towards green energy, long distance transportation of gaseous hydrogen by pipeline is considered to be an economically attractive solution. For safe transportation of hydrogen, it is important to conduct relevant mechanical tests in representative hydrogen environments and working conditions of pipelines to demonstrate acceptable hydrogen embrittlement resistance of the steel. One important issue is the testing condition for the ratio of gaseous hydrogen volume over specimen surface area required in mechanical testing since this has not been specified in any testing standards and codes or investigated. This study investigated this issue by performing slow strain rate tensile (SSRT) testing of an X52 pipeline steel in gaseous hydrogen with different ratios of hydrogen volume/specimen surface area, R-v/s, ml/mm(2). It was found that, with increasing R-v/s ratio, the area reduction of the steel decreased and hydrogen embrittlement sensitivity increased in the range of the R-v/s ratios investigated. The saturating R-v/s ratio appeared to be similar to 2.0 beyond which the effect of R-v/s ratio on hydrogen embrittlement sensitivity was relatively small. The macroscopic and microscopic observations on both the fracture and side surfaces of the SSRT tested specimens also found that the tendency to cleavage fracture increased with increasing R-v/s ratio. The results of the ab initio molecular dynamics (aimd) simulations performed also predicted a dependence of hydrogen embrittlement on hydrogen volume when R-v/s ratio is relatively small.

关键词： X52 pipeline steel Hydrogen volume/surface area ratio Slow strain rate tensile testing Hydrogen embrittlement sensitivity Quasi-cleavage fracture aimd simulation

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Electrochemical Properties of Mo4VC4T x MXene in Aqueous Electrolytes

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ACS APPLIED MATERIALS & INTERFACES 2024年第29期16卷 38053-38060页

作者： Hussain, Iftikhar Rehman, Faisal Saraf, Mohit Zhang, Teng Wang, Ruocun Das, Tridip Luo, Zhengtang Gogotsi, Yury Zhang, Kaili City Univ Hong Kong Dept Mech Engn Kowloon Hong Kong 19104 Peoples R China Drexel Univ AJ Drexel Nanomat Inst Philadelphia PA 19104 USA Drexel Univ Dept Mat Sci & Engn Philadelphia PA 19104 USA Hong Kong Univ Sci & Technol Dept Chem & Biol Engn Kowloon Hong Kong 19104 Peoples R China CALTECH Mat & Proc Simulat Ctr MC 139-74 Pasadena CA 91125 USA Univ Engn & Technol Lahore Dept Chem & Polymer Engn Faisalabad 38000 Pakistan

M5C4Tx MXenes represent the most recently discovered and least studied subfamily of out-of-plane ordered double transition metal carbides with 11 atomic layers, probably the thickest of all 2D materials. Molybdenum (Mo) and vanadium (V) in Mo4VC4Tx offer multiple oxidation states, making this MXene potentially attractive for electrochemical energy storage applications. Herein, we evaluated the electrochemical properties of Mo4VC4Tx free-standing thin films in acidic, basic, and neutral aqueous electrolytes and observed the highest gravimetric capacitance of 219 F g(-1) at 2 mV s(-1) in a 3 M H2SO4. Further, we investigated the intercalation states of four different cations (H+, Li+, Na+, and K+) in MXenes through ab initio molecular dynamics (aimd) simulation and used density functional theory (DFT) calculations to assess the charge storage mechanisms in different electrolytes. These studies show hydrated Li+, Na+, and K+ ions forming an electric double layer (EDL) at the MXene surface as the primary charge storage mechanism. This work shows the promise of Mo4VC4Tx MXene for energy storage in aqueous electrolytes.

关键词： Mo4VC4T x MXene DFT aimd simulation aqueouselectrolytes supercapacitors

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High capacity hydrogen storage structure based on a two-dimensional material (Ga2C6) with strong adsorption properties

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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY 2024年 68卷 1072-1079页

作者： Labrousse, J. Aziz, O. El Kenz, A. Benyoussef, A. Mohammed V Univ Fac Sci Dept Phys Lab Condensed Matter & Interdisciplinary Sci Rabat Morocco Hassan II Acad Sci & Technol Rabat Morocco

The use of solid -state devices is a promising approach to address the current technological requirements for sustainable clean energy applications. Within this context, it has become apparent that density functional theory (DFT) has emerged as a powerful tool to study intrinsic electronic characteristics and shows great potential to lead the way to novel materials exploration. Here, we have investigated H 2 adsorption on Ga 2 C 6 monolayer, a prospective model for the storage of H 2 molecule because of its structural stability. The hydrogen molecules favor being adsorbed at the carbon hexagon center with a binding energy of 0.39 eV. The thermodynamic stability of the Ga 2 C 6 monolayer upon adsorption of 22H 2 molecules was evaluated at room temperature using ab-initio molecular dynamics (aimd) simulations. It is found from the electronic structure analysis that the semiconducting Ga 2 C 6 sheet maintain its behavior after 22H 2 molecules were adsorbed. Owing to the small activation energy of about 0.0198 eV, the process of H 2 molecule migration at the surface easy proceeds. This investigation demonstrates a strong (G C ) gravimetric capacity around 9.65 wt%, and a desorption temperature (T D ) around 213.68 K. The above findings imply that the Ga 2 C 6 monolayer may serve as a suitable medium for hydrogen adsorption.

关键词： H2 adsorption DFT calculation aimd simulation Desorption temperature Gravimetric capacity

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Diffusion and Surface Segregation of Interstitial Ti Defects Induced by Electronic Metal-Support Interactions on a Au/TiO2 Nanocatalyst

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ACS CATALYSIS 2022年第8期12卷 4455-4464页

作者： Xia, Guang-Jie Lee, Mal-Soon Glezakou, Vassiliki-Alexandra Rousseau, Roger Wang, Yang-Gang Southern Univ Sci & Technol Dept Chem Shenzhen 518055 Guangdong Peoples R China Southern Univ Sci & Technol Guangdong Prov Key Lab Catalysis Shenzhen 518055 Guangdong Peoples R China Pacific Northwest Natl Lab Phys Sci Div Richland WA 99352 USA

Both the O vacancy and interstitial Ti are ubiquitous defect types found inreduced TiO2-xcatalytic support materials. Without a metal cluster, the interstitial Ti defect ismore stable in bulk of TiO2-xrather than becoming the Ti adatom on the reduced ***, it can slowly diffuse out to regrow TiO2islands after surface oxidation. However, forthe widely used Au/TiO2nanocatalyst, ab initio molecular dynamics simulation and densityfunctional theory calculation found, even under the reducing condition with O vacancy, that theAu cluster could induce the outward diffusion and surface segregation of interstitial Ti *** Au cluster, which acts as an electron reservoir, enables the interstitial Ti to shed excesselectrons and stabilize itself at the Au/TiO2interface. The electronic metal-support interaction not only makes this processexothermic but also reduces its diffusion barrier. When excess O2is further introduced, the TiO2islands can regrow at the metal-support interface to form the inverse supporting local sites. Comparatively speaking, the Au cluster plays a critical role overinterstitial Ti diffusion rates, while the additional O2stabilizes the regrowth of TiO2islands. Generally, the surface segregation ofinterstitial Ti defects could be more favorable for the metals with higher work function, such as Pt and Au, but less for thoseelectron-rich metals with a lower work function, such as Zn. Considering the ubiquity of support defects and the fact that the surfacesegregation is so facile under not only oxidating but also reducing conditions, we postulate that, in addition to O vacancies,interstitial Ti defects are also crucial for fully understanding the catalytic role of TiO2-supported metal catalysts.

关键词： titania interstitial defect gold electronic metal-support interaction surface segregation aimd simulation DFT calculation

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Unraveling oxidative aging behavior of asphaltenes using ab initio molecular dynamics and static density functional theory

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CONSTRUCTION AND BUILDING MATERIALS 2022年第0期318卷 126032-126032页

作者： Hu, Dongliang Gu, Xingyu Lyu, Lei Wang, Guoliang Cui, Bingyan Southeast Univ Sch Transportat Nanjing 211189 Jiangsu Peoples R China Southeast Univ Natl Demonstrat Ctr Expt Rd & Traff Engn Educ Nanjing 211189 Jiangsu Peoples R China Tibet Univ Coll Engn Lhasa 850000 Tibet Peoples R China Changan Univ Sch Highway Xian 710064 Shaanxi Peoples R China Rutgers State Univ Sch Engn Dept Civil & Environm Engn New Brunswick NJ USA

Asphalt aging is a major cause of cracking failure in asphalt pavement. However, owing to the lack of understanding of the asphalt aging mechanism, research on asphalt-targeted antiaging technology has encountered challenges. To address this issue, ab initio molecular dynamics simulations and density functional theory calculations based on the quantum chemistry framework were conducted to explore the reaction pathway and thermodynamic driving force of asphaltene aging. The physical properties of asphaltenes were evaluated to determine the effect of aging on asphaltene performance. The results indicate that asphaltenes undergo aging subreactions at different temperatures, including aromatization of naphthenes, formation of oxygen-containing groups, and homolysis of alkyl side chains. The free energy barriers of these reactions can be ranked in ascending order as aromatization < oxygen-containing group formation < homolysis. The molecular polarity, intermolecular binding energy, and solubility parameter of the asphaltene molecule increased significantly with aging, leading to enhanced agglomeration and reduced compatibility of asphalt components, resulting in the deterioration of asphalt cracking resistance.

关键词： aimd simulation Aging mechanism Antiaging Asphaltene aging DFT calculation

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