Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understan...Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understanding their petrological,chemical,and geophysical behaviors.In this study,we employed first-principles molecular dynamics simulations to explore the structures,self-diffusion coefficients(D),and viscosities(η)of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids under conditions of 2000 K and 3-10 GPa,with water contents of 30 wt% and 50 wt%.Our calculations indicate that at a water content of 30 wt%,Q^(2) and Q^(3) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species(n represents the number of bridging oxygens connected to Si/Al)show minimal changes.At a water content of 50 wt%,Q^(2) and Q^(0) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species show minimal changes.At both water contents,Si-O-H and molecular water in the system exhibit negative pressure dependence,suggesting that the migration of supercritical fluids from deep to shallow regions is accompanied by the release of water.The self-diffusion coefficients in the supercritical NaAlSi_(3)O_(8)-H_(2)O fluid follow the order D_(Na)≈D_(H)>D_(O)>D_(Al)≈D_(Si),with an overall weak negative pressure dependence.By comparing the viscosities of anhydrous and hydrous silicate melts from previous studies,we found that the addition of water caused a transition from negative to positive pressure dependence of viscosity,corresponding to a structural change from polymerization to depolymerization.Additionally,we calculated the fluid mobility Δp/η of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids and found that their mobility is several orders of magnitude higher than that of basalt melt and is also significantly greater than that of carbonate melt.As supercritical fluids ascend from deeper to shallower regions,their mobility is further enhanced,significantly contributing to the transport of elements from subducting slabs to the overlying mantle wedge.展开更多
P2型层状过渡金属氧化物(P2-Na_(x)TMO_(2))因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计...P2型层状过渡金属氧化物(P2-Na_(x)TMO_(2))因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计来克服这些挑战。通过在P2相高熵基体中引入O3相,构建新型P2/O3双相高熵层状氧化物Na_(0.70)Ni_(0.25)Mn_(0.35)Co_(0.15)Fe_(0.05)Ti_(0.20)O_(2)(简称Na_(0.70)NMCFT)。其中,高熵设计通过构型熵稳定效应有效抑制P2相的不可逆相变,而O3相则通过协同作用弥补容量不足并提升循环稳定性。此外,双相组分之间的相互作用进一步促进P2-O3与P2-P3相变的高度可逆性。Na_(0.70)NMCFT在1C倍率下的初始放电容量为102.08 mAhg^(-1),200次循环后容量保持率达88.15%,表明具有优异的循环稳定性。更重要的是,即使在10C的高倍率下,Na_(0.70)NMCFT仍能提供85.67 mAh g^(-1)的初始放电比容量,并在1000次循环后容量保持率达70%。本工作证实双相高熵设计在提升钠离子电池正极性能中的关键作用,为开发先进钠离子电池正极材料提供了新思路。展开更多
Quinoxalin-2(1H)-ones are unique nitrogen-containing organic compounds with wide applications in the agrochemical,pharmaceutical,and chemical industries as well as in material science.During the last decades,visible-l...Quinoxalin-2(1H)-ones are unique nitrogen-containing organic compounds with wide applications in the agrochemical,pharmaceutical,and chemical industries as well as in material science.During the last decades,visible-light-promoted photoredox catalysis has emerged as a versatile platform for constructing quinoxalin-2(1H)-one scaffolds under exceptionally mild conditions.In this review,we provide an overview of recent advances in photocatalytic direct C(3)–H functionalization of quinoxaline-2(1H)-ones,including the construction of C(3)–C bonds and C(3)–R_(F)/C/O/N/Cl/S/D bonds,as well as the related reaction mechanisms.We aim to enhance the methods for the reaction of quinoxalin-2(1H)-ones at the C-3 position,which have extensive applications in organic synthesis and medicinal chemistry.展开更多
Ternary blending as one of the most successful strategies has achieved continuous performance breakthroughs in organic solar cells(OSCs)over the past few years.Here,a small molecule featuring a dithieno[3,2-f:2′,3′-...Ternary blending as one of the most successful strategies has achieved continuous performance breakthroughs in organic solar cells(OSCs)over the past few years.Here,a small molecule featuring a dithieno[3,2-f:2′,3′-h]phthalimide derivative as the intermediate unit,named DTP-C8-R,is designed and utilized as the third component to construct ternary OSCs(TOSCs).The increased molecular packing of L8-BO as well as the charge transfer excitons between PM6 and DTP-C8-R lead to a very low nonradiative energy loss of 0.179 eV and a high open-circuit voltage(V_(OC))of 0.910 V in the TOSCs based on the PM6:L8-BO host blend.Moreover,the DTP-C8-R:PM6:L8-BO film(0.05:0.95:1.2,w/w)possesses better fibrous nanophase separation and the enhancedπ-πstacking ordering of the acceptors with a larger crystal coherence length compared with the PM6:L8-BO blend film,so the TOSCs present more efficient exciton dissociation,longer carrier lifetime,faster carrier transport and less charge recombination.It boosts the power conversion efficiency to 19.22%with a short-circuit current density of 27.10 mA cm^(-2).This work demonstrates that the small molecule based on a dithieno[3,2-f:2′,3′-h]phthalimide derivative as the minor component is an executable strategy to achieve high-performance TOSCs with high V_(OC).展开更多
基金funded by National Natural Science Foundation of China(42373033,Yicheng Sun)Fundamental Research Funds for the Central Universities(B240201111,Yicheng Sun)。
文摘Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understanding their petrological,chemical,and geophysical behaviors.In this study,we employed first-principles molecular dynamics simulations to explore the structures,self-diffusion coefficients(D),and viscosities(η)of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids under conditions of 2000 K and 3-10 GPa,with water contents of 30 wt% and 50 wt%.Our calculations indicate that at a water content of 30 wt%,Q^(2) and Q^(3) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species(n represents the number of bridging oxygens connected to Si/Al)show minimal changes.At a water content of 50 wt%,Q^(2) and Q^(0) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species show minimal changes.At both water contents,Si-O-H and molecular water in the system exhibit negative pressure dependence,suggesting that the migration of supercritical fluids from deep to shallow regions is accompanied by the release of water.The self-diffusion coefficients in the supercritical NaAlSi_(3)O_(8)-H_(2)O fluid follow the order D_(Na)≈D_(H)>D_(O)>D_(Al)≈D_(Si),with an overall weak negative pressure dependence.By comparing the viscosities of anhydrous and hydrous silicate melts from previous studies,we found that the addition of water caused a transition from negative to positive pressure dependence of viscosity,corresponding to a structural change from polymerization to depolymerization.Additionally,we calculated the fluid mobility Δp/η of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids and found that their mobility is several orders of magnitude higher than that of basalt melt and is also significantly greater than that of carbonate melt.As supercritical fluids ascend from deeper to shallower regions,their mobility is further enhanced,significantly contributing to the transport of elements from subducting slabs to the overlying mantle wedge.
文摘P2型层状过渡金属氧化物(P2-Na_(x)TMO_(2))因其优异的循环稳定性和倍率性能,成为钠离子电池正极材料的有力候选者。然而,其在高电压下的不可逆相变和固有低理论容量问题,阻碍了实际应用。本研究工作提出高熵策略与双相结构的协同设计来克服这些挑战。通过在P2相高熵基体中引入O3相,构建新型P2/O3双相高熵层状氧化物Na_(0.70)Ni_(0.25)Mn_(0.35)Co_(0.15)Fe_(0.05)Ti_(0.20)O_(2)(简称Na_(0.70)NMCFT)。其中,高熵设计通过构型熵稳定效应有效抑制P2相的不可逆相变,而O3相则通过协同作用弥补容量不足并提升循环稳定性。此外,双相组分之间的相互作用进一步促进P2-O3与P2-P3相变的高度可逆性。Na_(0.70)NMCFT在1C倍率下的初始放电容量为102.08 mAhg^(-1),200次循环后容量保持率达88.15%,表明具有优异的循环稳定性。更重要的是,即使在10C的高倍率下,Na_(0.70)NMCFT仍能提供85.67 mAh g^(-1)的初始放电比容量,并在1000次循环后容量保持率达70%。本工作证实双相高熵设计在提升钠离子电池正极性能中的关键作用,为开发先进钠离子电池正极材料提供了新思路。
基金support from the National Natural Science Foundation of China(No.22101267)the China Postdoctoral Science Foundation(Nos.2021M692905 and 2024T170832)+2 种基金Natural Science Foundation of Henan Province,China(No.242300421123)Scientific Research Project of Hubei Provincial Education Department,China(No.Q20233104)Hubei Provincial Natural Science Foundation,China(No.2024AFB946).
文摘Quinoxalin-2(1H)-ones are unique nitrogen-containing organic compounds with wide applications in the agrochemical,pharmaceutical,and chemical industries as well as in material science.During the last decades,visible-light-promoted photoredox catalysis has emerged as a versatile platform for constructing quinoxalin-2(1H)-one scaffolds under exceptionally mild conditions.In this review,we provide an overview of recent advances in photocatalytic direct C(3)–H functionalization of quinoxaline-2(1H)-ones,including the construction of C(3)–C bonds and C(3)–R_(F)/C/O/N/Cl/S/D bonds,as well as the related reaction mechanisms.We aim to enhance the methods for the reaction of quinoxalin-2(1H)-ones at the C-3 position,which have extensive applications in organic synthesis and medicinal chemistry.
基金financially supported by the National Natural Science Foundation of China(51873177,52303252)the Natural Science Foundation of Hunan Province(2024JJ4039)+1 种基金the Advanced Photoelectricity and Supramolecular Functional Materials of the Ministry of Education(IRT-17R90)the Hunan 2011 Collaborative Innovation Centre of Chemical Engineering&Technology with Environmental Benignity and Effective Resource Utilization。
文摘Ternary blending as one of the most successful strategies has achieved continuous performance breakthroughs in organic solar cells(OSCs)over the past few years.Here,a small molecule featuring a dithieno[3,2-f:2′,3′-h]phthalimide derivative as the intermediate unit,named DTP-C8-R,is designed and utilized as the third component to construct ternary OSCs(TOSCs).The increased molecular packing of L8-BO as well as the charge transfer excitons between PM6 and DTP-C8-R lead to a very low nonradiative energy loss of 0.179 eV and a high open-circuit voltage(V_(OC))of 0.910 V in the TOSCs based on the PM6:L8-BO host blend.Moreover,the DTP-C8-R:PM6:L8-BO film(0.05:0.95:1.2,w/w)possesses better fibrous nanophase separation and the enhancedπ-πstacking ordering of the acceptors with a larger crystal coherence length compared with the PM6:L8-BO blend film,so the TOSCs present more efficient exciton dissociation,longer carrier lifetime,faster carrier transport and less charge recombination.It boosts the power conversion efficiency to 19.22%with a short-circuit current density of 27.10 mA cm^(-2).This work demonstrates that the small molecule based on a dithieno[3,2-f:2′,3′-h]phthalimide derivative as the minor component is an executable strategy to achieve high-performance TOSCs with high V_(OC).
