Pub Date : 2025-04-19DOI: 10.1016/j.chemphys.2025.112745
Yuanyuan Wang , Xingshen Dong , Yingjing Xia , WenYi Wang , Hua Song , Shetian Liu
Heteroatom-doped porous carbon materials have gained extensive application as electrode materials for supercapacitors. Nitrogen-doped porous carbon materials (NPPCPC-y) were prepared using dicyandiamide as the nitrogen dopant and the husk of Physalis (Physalis pubescens L.) as the carbon source. NPPCPC-1 exhibits a nitrogen content of 11.28 % and a specific surface area of 1677.19 m2·g−1. Notably, NPPCPC-1 demonstrates excellent capacitance performance of 255.9 F·g−1 at 50 A·g−1 and high rate capability of 387.9 F·g−1 at 0.5 A·g−1. In a two-electrode system, NPPCPC-1//NPPCPC-1 exhibits a wide operating voltage range of 2.2 V in 1 M Na2SO4, delivering an energy density exceeding 30 Wh·kg−1 (1100 W·kg−1). Additionally, the NPPCPC-1//NPPCPC-1 undergoes 20,000 continuous charge-discharge cycles (10 A·g−1 in KOH electrolyte) while maintaining a capacitance retention of over 99 %.
{"title":"High-performance nitrogen-doped porous carbon materials derived from waste biomass for supercapacitors","authors":"Yuanyuan Wang , Xingshen Dong , Yingjing Xia , WenYi Wang , Hua Song , Shetian Liu","doi":"10.1016/j.chemphys.2025.112745","DOIUrl":"10.1016/j.chemphys.2025.112745","url":null,"abstract":"<div><div>Heteroatom-doped porous carbon materials have gained extensive application as electrode materials for supercapacitors. Nitrogen-doped porous carbon materials (NPPCPC-<em>y</em>) were prepared using dicyandiamide as the nitrogen dopant and the husk of Physalis (<em>Physalis pubescens</em> L.) as the carbon source. NPPCPC-1 exhibits a nitrogen content of 11.28 % and a specific surface area of 1677.19 m<sup>2</sup>·g<sup>−1</sup>. Notably, NPPCPC-1 demonstrates excellent capacitance performance of 255.9 F·g<sup>−1</sup> at 50 A·g<sup>−1</sup> and high rate capability of 387.9 F·g<sup>−1</sup> at 0.5 A·g<sup>−1</sup>. In a two-electrode system, NPPCPC-1//NPPCPC-1 exhibits a wide operating voltage range of 2.2 V in 1 M Na<sub>2</sub>SO<sub>4</sub>, delivering an energy density exceeding 30 Wh·kg<sup>−1</sup> (1100 W·kg<sup>−1</sup>). Additionally, the NPPCPC-1//NPPCPC-1 undergoes 20,000 continuous charge-discharge cycles (10 A·g<sup>−1</sup> in KOH electrolyte) while maintaining a capacitance retention of over 99 %.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112745"},"PeriodicalIF":2.0,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.chemphys.2025.112747
Jahid Kabir Rony , Md Saiduzzaman , Mohammad Nazmul Hasan , Md N.J. Rifat , Minhajul Islam
Inorganic metal halide perovskites have garnered significant interest from researchers due to their diverse applications across various scientific and engineering fields. Recognizing their importance, the key physical properties of cubic metal halide perovskites MPbI3 (M = K, Tl) were investigated under applied pressures ranging from 0 to 6 GPa using density functional theory (DFT)-based ab-initio calculations. The lattice constant, cell volume, and band gap decrease significantly under the influence of pressure, leading to enhanced atomic interactions. The stability of both materials is confirmed by their formation energy, Goldschmidt tolerance factor, Born stability criteria, and phonon dispersion. The calculated band gap values show improved accuracy for both KPbI3 (2.16 eV) and TlPbI3 (2.40 eV) when the hybrid HSE06 functional is utilized. The band gap calculated using the HSE06 functional agrees closely with the available experimental data for KPbI3 (2.19 eV). As pressure increases, the bond lengths decrease monotonically, resulting in the strengthening of both the ionic and covalent bonds. The changes in optical properties due to pressure are significant, such as the optical absorption and conductivity, which have increased as the band gap decreased. The performance of optoelectronic devices depends much on optical functions, and the compounds with higher pressure show greater performance. Pressure has an influence on mechanical properties because the presence of external pressure produces compounds with more ductility and anisotropy. The ductility and anisotropy, both under hydrostatic pressure and at ambient conditions, exhibit the trend: TlPbI3 > KPbI3. Throughout the study, TlPbI3 consistently outperforms KPbI3 due to its superior physical properties across all evaluated parameters. We believe this investigation will contribute to the development of more efficient solar cells, ionizing radiation detectors, and advanced optoelectronic devices using inorganic KPbI3 and TlPbI3.
{"title":"Pressure-controlled enhancement of key physical properties for improved optoelectronic performance in MPbI3 (M = K, Tl) perovskites","authors":"Jahid Kabir Rony , Md Saiduzzaman , Mohammad Nazmul Hasan , Md N.J. Rifat , Minhajul Islam","doi":"10.1016/j.chemphys.2025.112747","DOIUrl":"10.1016/j.chemphys.2025.112747","url":null,"abstract":"<div><div>Inorganic metal halide perovskites have garnered significant interest from researchers due to their diverse applications across various scientific and engineering fields. Recognizing their importance, the key physical properties of cubic metal halide perovskites MPbI<sub>3</sub> (M = K, Tl) were investigated under applied pressures ranging from 0 to 6 GPa using density functional theory (DFT)-based ab-initio calculations. The lattice constant, cell volume, and band gap decrease significantly under the influence of pressure, leading to enhanced atomic interactions. The stability of both materials is confirmed by their formation energy, Goldschmidt tolerance factor, Born stability criteria, and phonon dispersion. The calculated band gap values show improved accuracy for both KPbI<sub>3</sub> (2.16 eV) and TlPbI<sub>3</sub> (2.40 eV) when the hybrid HSE06 functional is utilized. The band gap calculated using the HSE06 functional agrees closely with the available experimental data for KPbI<sub>3</sub> (2.19 eV). As pressure increases, the bond lengths decrease monotonically, resulting in the strengthening of both the ionic and covalent bonds. The changes in optical properties due to pressure are significant, such as the optical absorption and conductivity, which have increased as the band gap decreased. The performance of optoelectronic devices depends much on optical functions, and the compounds with higher pressure show greater performance. Pressure has an influence on mechanical properties because the presence of external pressure produces compounds with more ductility and anisotropy. The ductility and anisotropy, both under hydrostatic pressure and at ambient conditions, exhibit the trend: TlPbI<sub>3</sub> > KPbI<sub>3</sub>. Throughout the study, TlPbI<sub>3</sub> consistently outperforms KPbI<sub>3</sub> due to its superior physical properties across all evaluated parameters. We believe this investigation will contribute to the development of more efficient solar cells, ionizing radiation detectors, and advanced optoelectronic devices using inorganic KPbI<sub>3</sub> and TlPbI<sub>3</sub>.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112747"},"PeriodicalIF":2.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143844626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-17DOI: 10.1016/j.chemphys.2025.112748
K.L. Ngai , Yanhui Zhang , S. Capaccioli , Li-Min Wang
Since its inception in 1979, the Coupling Model have predicted universality of the dynamic processes and their properties in glass-forming materials irrespective of physical structure and chemical composition. The three major dynamic processes are the caged dynamics at early times, the intermediary primitive and the Johari-Goldstein β relaxation, and the terminal structural α relaxation. They are coupled together, and thus their properties are interrelated and universal. Experiments and simulations data of many different classes of glass-forming materials analyzed over the past 45 years and collected in the review, Prog. Mater. Sci.2023, 139, 101130, have verified extensively the prediction of universality of the interrelated properties. In this paper we performed critical tests of the universal interrelated properties of the three processes in water involved in its liquid-glass transition problem. The positive results from the tests show water is no exception. The universal properties found in water have the benefits of solving the glass transition problem of water and resolving the controversies that last over several decades. Controversies instead of solutions in the past were due to failure to include caged dynamics and Johari-Goldstein β relaxation and their linkage to the structural α relaxation of water in interpreting the experimental data.
{"title":"Properties of processes associated with the glass transition of water are isomorphic to those of other glass-formers","authors":"K.L. Ngai , Yanhui Zhang , S. Capaccioli , Li-Min Wang","doi":"10.1016/j.chemphys.2025.112748","DOIUrl":"10.1016/j.chemphys.2025.112748","url":null,"abstract":"<div><div>Since its inception in 1979, the Coupling Model have predicted universality of the dynamic processes and their properties in glass-forming materials irrespective of physical structure and chemical composition. The three major dynamic processes are the caged dynamics at early times, the intermediary primitive and the Johari-Goldstein β relaxation, and the terminal structural α relaxation. They are coupled together, and thus their properties are interrelated and universal. Experiments and simulations data of many different classes of glass-forming materials analyzed over the past 45 years and collected in the review, <em>Prog. Mater. Sci.</em> <strong>2023</strong>, <em>139</em>, 101130, have verified extensively the prediction of universality of the interrelated properties. In this paper we performed critical tests of the universal interrelated properties of the three processes in water involved in its liquid-glass transition problem. The positive results from the tests show water is no exception. The universal properties found in water have the benefits of solving the glass transition problem of water and resolving the controversies that last over several decades. Controversies instead of solutions in the past were due to failure to include caged dynamics and Johari-Goldstein β relaxation and their linkage to the structural α relaxation of water in interpreting the experimental data.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112748"},"PeriodicalIF":2.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Unsymmetrical dimethylhydrazine (UDMH), a widely used liquid propellant, has garnered significant attention for its environmental monitoring challenges. This study explores the adsorption properties and reaction mechanisms of UDMH and oxygen on the Cu2O (111) surface through first-principles calculations and molecular dynamics simulations. Initially, adsorption energies and charge transfer dynamics were analyzed at various adsorption sites, revealing strong adsorption capacities for both UDMH and oxygen. Subsequently, molecular dynamics simulations elucidated the reaction pathways between UDMH and oxygen on the Cu2O (111) surface. The results indicate that UDMH undergoes rapid redox reactions with oxygen, forming multiple stable compounds. This highlights the substantial impact of oxygen on the accuracy of UDMH concentration detection by Cu2O-based sensors. These findings provide valuable insights for improving the design and functionality of gas-sensitive materials for UDMH detection.
{"title":"Adsorption and reaction mechanism of UDMH and O2 on Cu2O (111) surface: A combined first-principles and reactive molecular dynamics study","authors":"Hao-yang Wang, Ying Jia, Xiao-meng Lv, Wan-ting Zhou","doi":"10.1016/j.chemphys.2025.112750","DOIUrl":"10.1016/j.chemphys.2025.112750","url":null,"abstract":"<div><div>Unsymmetrical dimethylhydrazine (UDMH), a widely used liquid propellant, has garnered significant attention for its environmental monitoring challenges. This study explores the adsorption properties and reaction mechanisms of UDMH and oxygen on the Cu<sub>2</sub>O (111) surface through first-principles calculations and molecular dynamics simulations. Initially, adsorption energies and charge transfer dynamics were analyzed at various adsorption sites, revealing strong adsorption capacities for both UDMH and oxygen. Subsequently, molecular dynamics simulations elucidated the reaction pathways between UDMH and oxygen on the Cu<sub>2</sub>O (111) surface. The results indicate that UDMH undergoes rapid redox reactions with oxygen, forming multiple stable compounds. This highlights the substantial impact of oxygen on the accuracy of UDMH concentration detection by Cu<sub>2</sub>O-based sensors. These findings provide valuable insights for improving the design and functionality of gas-sensitive materials for UDMH detection.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112750"},"PeriodicalIF":2.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143848434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The mounting interest in conducting thorough analyses and studies of long-range interactions stems from their wide-ranging applications in cold atomic physics, making it a compelling area for research. In this work, we have evaluated long range van der Waals dispersion (vdW) interactions of Cu and Ag atoms with atoms of group I (Li, Na, K, Rb, Cs, and Fr), II (Be, Mg, Ca, Sr, and Ba), XII (Zn, Cd, and Hg) as well as singly charged ions of group II (Be, Mg, Ca, Sr, and Ba) and XII (Zn, Cd, and Hg) by calculating (two-body) and (three-body) vdW dispersion coefficients. In order to obtain these and coefficients, we have evaluated the dynamic dipole polarizability of the considered atoms using appropriate relativistic methods and the sum-over-states approach. To ascertain the accuracy of our results, we have compared the evaluated static dipole polarizabilities of Cu and Ag atoms and their oscillator strengths for dominant transitions with available literature. The calculated values of dispersion coefficients have also been compared with the previously reported results.
{"title":"Two- and three-body dispersion coefficients for interaction of Cu and Ag atoms with Group I, II, and XII elements","authors":"Harpreet Kaur , Jyoti , Neelam Shukla , Bindiya Arora","doi":"10.1016/j.chemphys.2025.112731","DOIUrl":"10.1016/j.chemphys.2025.112731","url":null,"abstract":"<div><div>The mounting interest in conducting thorough analyses and studies of long-range interactions stems from their wide-ranging applications in cold atomic physics, making it a compelling area for research. In this work, we have evaluated long range van der Waals dispersion (vdW) interactions of Cu and Ag atoms with atoms of group I (Li, Na, K, Rb, Cs, and Fr), II (Be, Mg, Ca, Sr, and Ba), XII (Zn, Cd, and Hg) as well as singly charged ions of group II (Be<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, Mg<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, Ca<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, Sr<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, and Ba<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>) and XII (Zn<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, Cd<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>, and Hg<span><math><msup><mrow></mrow><mrow><mo>+</mo></mrow></msup></math></span>) by calculating <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span>(two-body) and <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>9</mn></mrow></msub></math></span> (three-body) vdW dispersion coefficients. In order to obtain these <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span> and <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>9</mn></mrow></msub></math></span> coefficients, we have evaluated the dynamic dipole polarizability of the considered atoms using appropriate relativistic methods and the sum-over-states approach. To ascertain the accuracy of our results, we have compared the evaluated static dipole polarizabilities of Cu and Ag atoms and their oscillator strengths for dominant transitions with available literature. The calculated values of <span><math><msub><mrow><mi>C</mi></mrow><mrow><mn>6</mn></mrow></msub></math></span> dispersion coefficients have also been compared with the previously reported results.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112731"},"PeriodicalIF":2.0,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143848433","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study systematically investigates the effects of 34 metallic dopants on the {} grain boundary in Yttrium-based alloys using first-principles calculations. Results reveal a strong segregation tendency of dopants near the grain boundary due to favorable segregation energies, with energy barriers influencing segregation positions. Strengthening energy calculations show all dopants enhance grain boundary strength when located nearby. Considering the stability of the grain boundary, 11 elements (Al, Zn, etc) are identified as preferentially segregating near the grain boundary, contributing to enhanced strength and stability. Trends in grain boundary energy and solubility among transition group elements correlate with valence electrons. Decomposition of strengthening energy reveals that chemical contributions dominate, while mechanical effects correlate with changes in Voronoi volume and solute atomic radius. DOS analysis indicates that hybridization between solutes and Yttrium d orbitals stabilizes the grain boundary. This study provides theoretical insights for optimizing dopants in Y-based alloys.
{"title":"First-principles insights into metallic doping effects on yttrium twin grain boundary","authors":"Guanlin Lyu, Yuanxu Zhu, Yuguo Sun, Panpan Gao, Ping Qian","doi":"10.1016/j.chemphys.2025.112742","DOIUrl":"10.1016/j.chemphys.2025.112742","url":null,"abstract":"<div><div>This study systematically investigates the effects of 34 metallic dopants on the {<span><math><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn></math></span>} grain boundary in Yttrium-based alloys using first-principles calculations. Results reveal a strong segregation tendency of dopants near the grain boundary due to favorable segregation energies, with energy barriers influencing segregation positions. Strengthening energy calculations show all dopants enhance grain boundary strength when located nearby. Considering the stability of the grain boundary, 11 elements (Al, Zn, etc) are identified as preferentially segregating near the grain boundary, contributing to enhanced strength and stability. Trends in grain boundary energy and solubility among transition group elements correlate with valence electrons. Decomposition of strengthening energy reveals that chemical contributions dominate, while mechanical effects correlate with changes in Voronoi volume and solute atomic radius. DOS analysis indicates that hybridization between solutes and Yttrium d orbitals stabilizes the grain boundary. This study provides theoretical insights for optimizing dopants in Y-based alloys.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"596 ","pages":"Article 112742"},"PeriodicalIF":2.0,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143833963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-11DOI: 10.1016/j.chemphys.2025.112738
Qian Gao, Junfeng Xu
The frequently used m0.33, determined by the glass transition temperature Tg,0.33 at a heating rate q = 0.33 K/s in numerous studies, is compared with the Angell fragility parameter mη, derived from Tg,η at a viscosity of η = 1012 Pa s. Although m0.33 exhibits an overall increasing trend with mη, it does not accurately quantify the degree of deviation from the Arrhenius relation of η. Several counterexamples indicate that a larger m0.33 can correspond to a smaller mη. For 23 kinds of metallic glass-forming liquids, Tg,0.33 corresponds to viscosities ranging from 7.7 × 107 Pa s to 1.5 × 1012 Pa s. Consequently, m0.33 is determined under non-uniform viscosity standards, making it unsuitable for accurately evaluating the departure of η from Arrhenius temperature dependence. However, m0.33 can be converted to mη by multiplying by a factor λ = (Tg,η/Tg,0.33) × [(Tg,0.33-T0)/(Tg,η-T0)]2, where T0 is the kinetic ideal glass transition temperature. The ratio Tg,η/Tg,0.33 is 0.962, with a high R2 = 0.979. By using Tg,η ≈ 0.962Tg,0.33, a simpler approximate expression can be given as mη ≈ 0.962 × {(1-χ)/(0.962-χ)}2m0.33, where χ is T0/Tg.
{"title":"Study on the effect of glass transition temperature on fragility parameter in metallic glass-forming liquids","authors":"Qian Gao, Junfeng Xu","doi":"10.1016/j.chemphys.2025.112738","DOIUrl":"10.1016/j.chemphys.2025.112738","url":null,"abstract":"<div><div>The frequently used <em>m</em><sub>0.33</sub>, determined by the glass transition temperature <em>T</em><sub>g,0.33</sub> at a heating rate <em>q</em> = 0.33 K/s in numerous studies, is compared with the Angell fragility parameter <em>m</em><sub>η</sub>, derived from <em>T</em><sub>g,η</sub> at a viscosity of <em>η</em> = 10<sup>12</sup> Pa s. Although <em>m</em><sub>0.33</sub> exhibits an overall increasing trend with <em>m</em><sub>η</sub>, it does not accurately quantify the degree of deviation from the Arrhenius relation of <em>η</em>. Several counterexamples indicate that a larger <em>m</em><sub>0.33</sub> can correspond to a smaller <em>m</em><sub>η</sub>. For 23 kinds of metallic glass-forming liquids, <em>T</em><sub>g,0.33</sub> corresponds to viscosities ranging from 7.7 × 10<sup>7</sup> Pa s to 1.5 × 10<sup>12</sup> Pa s. Consequently, <em>m</em><sub>0.33</sub> is determined under non-uniform viscosity standards, making it unsuitable for accurately evaluating the departure of <em>η</em> from Arrhenius temperature dependence. However, <em>m</em><sub>0.33</sub> can be converted to <em>m</em><sub>η</sub> by multiplying by a factor λ = (<em>T</em><sub>g,η</sub>/<em>T</em><sub>g,0.33</sub>) × [(<em>T</em><sub>g,0.33</sub>-<em>T</em><sub>0</sub>)/(<em>T</em><sub>g,η</sub>-<em>T</em><sub>0</sub>)]<sup>2</sup>, where <em>T</em><sub>0</sub> is the kinetic ideal glass transition temperature. The ratio <em>T</em><sub>g,η</sub>/<em>T</em><sub>g,0.33</sub> is 0.962, with a high <em>R</em><sup>2</sup> = 0.979. By using <em>T</em><sub>g,η</sub> ≈ 0.962<em>T</em><sub>g,0.33</sub>, a simpler approximate expression can be given as <em>m</em><sub>η</sub> ≈ 0.962 × {(1-<em>χ</em>)/(0.962-<em>χ</em>)}<sup>2</sup><em>m</em><sub>0.33</sub>, where <em>χ</em> is <em>T</em><sub>0</sub>/<em>T</em><sub>g</sub>.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"595 ","pages":"Article 112738"},"PeriodicalIF":2.0,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143824690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-11DOI: 10.1016/j.chemphys.2025.112739
Mihade El Akkel, Hamid Ez-Zahraouy
This study represents the first comprehensive investigation into the photocatalytic performance of the double halide perovskite K2SeBr6 for hydrogen production via water splitting, employing density functional theory (DFT) as implemented in WIEN2k. The research encompasses an in-depth analysis of the structural, elastic, electronic, optical, transport, and photocatalytic properties of K2SeBr6. The findings reveal that K2SeBr6 fulfills the thermodynamic prerequisites for driving the water-splitting reaction. However, its band edges are significantly far from the water redox potentials, resulting in slower reaction kinetics. To address this limitation, the study investigates the application of tensile triaxial strains (2 %, 4 %, and 6 %). Tensile strain application reduces the bandgap energy, shifts optical absorption into the visible spectrum, and enhances the kinetics of the photocatalytic reactions. Additionally, the influence of pH on the photocatalytic efficiency of K2SeBr6 was thoroughly examined. Beyond its application in water splitting, the study explores the potential of K2SeBr6 for detecting and reducing CO2 into useful chemicals and fuels. These findings propose effective strategies for optimizing K2SeBr6 as a multifunctional material, particularly as an efficient photocatalyst for solar-driven hydrogen production.
{"title":"First-principles study of triaxial strain effect on structural, mechanical, electronic, optical, and photocatalytic properties of K2SeBr6 for solar hydrogen production","authors":"Mihade El Akkel, Hamid Ez-Zahraouy","doi":"10.1016/j.chemphys.2025.112739","DOIUrl":"10.1016/j.chemphys.2025.112739","url":null,"abstract":"<div><div>This study represents the first comprehensive investigation into the photocatalytic performance of the double halide perovskite K<sub>2</sub>SeBr<sub>6</sub> for hydrogen production via water splitting, employing density functional theory (DFT) as implemented in WIEN2k. The research encompasses an in-depth analysis of the structural, elastic, electronic, optical, transport, and photocatalytic properties of K<sub>2</sub>SeBr<sub>6</sub>. The findings reveal that K<sub>2</sub>SeBr<sub>6</sub> fulfills the thermodynamic prerequisites for driving the water-splitting reaction. However, its band edges are significantly far from the water redox potentials, resulting in slower reaction kinetics. To address this limitation, the study investigates the application of tensile triaxial strains (2 %, 4 %, and 6 %). Tensile strain application reduces the bandgap energy, shifts optical absorption into the visible spectrum, and enhances the kinetics of the photocatalytic reactions. Additionally, the influence of pH on the photocatalytic efficiency of K<sub>2</sub>SeBr<sub>6</sub> was thoroughly examined. Beyond its application in water splitting, the study explores the potential of K<sub>2</sub>SeBr<sub>6</sub> for detecting and reducing CO<sub>2</sub> into useful chemicals and fuels. These findings propose effective strategies for optimizing K<sub>2</sub>SeBr<sub>6</sub> as a multifunctional material, particularly as an efficient photocatalyst for solar-driven hydrogen production.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"595 ","pages":"Article 112739"},"PeriodicalIF":2.0,"publicationDate":"2025-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143828515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-04-09DOI: 10.1016/j.chemphys.2025.112737
Yan-Jun Liu , Qian Wang , Cong Xu , Rui-Zhe Zhang , Cai-Xia Hou , Wen-Jia Hu , Ting Lu , Ying-Hua Liang
The alkali‑oxygen oxidation of oil shale is a useful method to study the structural characteristics and produce carboxylic acids (CAs). However, this approach usually only obtains the average structural parameters and just examines oxidation product distribution. The information regarding reaction pathway and mechanism is not discussed in detail. In this study, a combination of experimental and computational methods was applied to investigate the alkaline‑oxygen oxidation mechanism of Yilan oil shale. In the oxidation process, 56.1 wt% yield of CAs can be obtained. By characterizing degradation pathway of organic carbon in oil shale, the degradation pathway was concluded. By analyzing molecular dynamics simulation trajectories, intermediates and elementary reactions involved in carbon structure were tracked. The ReaxFF results showed that the reaction followed a chain-reaction pathway, which included side-chain oxidation, aromatic carbon oxidation, and decarboxylation steps. Formaldehyde and carbonyl/phenolic hydroxyl groups were the active sites for carboxyl group formation.
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Pub Date : 2025-04-08DOI: 10.1016/j.chemphys.2025.112732
Mojtaba Gholami
Using DFT-based first-principles calculations, we investigate vacancy defects and non-metallic substitution doping (N, P, As) in the GeO₂ monolayer. Ge(O) vacancies induce significant magnetic moments of 3.7 and 7.8 μB for single and double vacancies, respectively, while O vacancies do not generate magnetism. Doping at O sites induces magnetic moments of 1.00, 0.90, and 0.90 μB for N, P, and As, respectively. Substitution at Ge sites results in 0.60 and 0.54 μB for N and As, whereas P doping does not induce magnetism. These modifications also alter the electronic structure: removing two Ge atoms leads to a semimetallic state, P doping at O sites induces semimetallicity, and P doping at Ge sites results in a metallic phase. These findings offer insights into defect engineering and doping in 2D materials, demonstrating their potential for spintronic and optoelectronic applications.
{"title":"Effects of vacancy defect and nonmetal (N, P, and as) impurities on electronic and magnetic properties of nonmagnetic-semiconductor GeO2 monolayer: A first-principles investigation","authors":"Mojtaba Gholami","doi":"10.1016/j.chemphys.2025.112732","DOIUrl":"10.1016/j.chemphys.2025.112732","url":null,"abstract":"<div><div>Using DFT-based first-principles calculations, we investigate vacancy defects and non-metallic substitution doping (N, P, As) in the GeO₂ monolayer. Ge(O) vacancies induce significant magnetic moments of 3.7 and 7.8 μB for single and double vacancies, respectively, while O vacancies do not generate magnetism. Doping at O sites induces magnetic moments of 1.00, 0.90, and 0.90 μB for N, P, and As, respectively. Substitution at Ge sites results in 0.60 and 0.54 μB for N and As, whereas P doping does not induce magnetism. These modifications also alter the electronic structure: removing two Ge atoms leads to a semimetallic state, P doping at O sites induces semimetallicity, and P doping at Ge sites results in a metallic phase. These findings offer insights into defect engineering and doping in 2D materials, demonstrating their potential for spintronic and optoelectronic applications.</div></div>","PeriodicalId":272,"journal":{"name":"Chemical Physics","volume":"595 ","pages":"Article 112732"},"PeriodicalIF":2.0,"publicationDate":"2025-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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