检索结果-南通市图书馆

Symmetry-breaking of LiMn6 hexatomic-ring in grain surface of Li2MnO3

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第6期81卷 110-117页

作者： Lihang Wang Shu Zhao Boya Wang Haijun Yu Institute of advanced Battery materials and Devices Faculty of Materials and Manufacturing Beijing University of Technology Key Laboratory of Advanced Functional Materials Ministry of Education Beijing University of Technology

LiMn6hexatomic-rings act as functional units in Li-rich layered oxides(LLOs), which determine the capacity, voltage, and structural stability of LLOs. However, the symmetry of the LiMn6hexatomic-ring is always broken, especially in the grain surface of LLOs, which will greatly affect its electrochemical performance. Herein, the symmetry-breaking of LiMn6hexatomic-ring in the grain surface of Li2MnO3was studied, and their effect on charge compensation mechanism and structure evolution behavior was thoroughly investigated. The results show that the electrochemical activity of the symmetry-broken LiMn6hexatomic-ring is higher than that of the unbroken LiMn6, and the former is more favorable for spinelization on the grain surface. Furthermore, the exposure proportion of crystallographic planes with different symmetry-broken LiMn6hexatomic-ring has also been discussed, which can be adjusted by changing the partial pressure of oxygen. The in-depth understanding of the symmetry-breaking of LiMn6hexatomic-ring will provide more targeted strategies for designing high-performance LLOs cathodes for lithium-ion batteries.

关键词： Li-rich layered oxides LiMn6 functional unit Symmetry-breaking Surface structure Density functional theory

Grain-boundary segregation and grain growth in nanocrystalline substitutional solid solution alloys

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2024年第1期168卷 239-249页

作者： Fawei Tang Chao Hou Hao Lu Zhi Zhao Xiaoyan Song Faculty of materials and Manufacturing Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of TechnologyBeijing 100124China

A model for describing solute segregation at grain boundaries has been developed for substitutional solid solution alloys,which integrates multiple factors from atomic to microstructural scales.A concept of mo-lar Gibbs free energy of segregation was introduced to evaluate the segregating capability of the solute elements in a closed system,through which the influences of grain boundary structure,grain size,ma-terial composition,and external conditions were described.Based on the evaluation of various energy forms related to solute segregation and grain growth processes,the nature of the thermal stabilization of nanograin structures by solute segregation was disclosed.A criterion for the destabilization of nanostruc-tures,which is determined by the competition of the change rates between the molar Gibbs free energy of segregation and the total energy of grain boundaries with grain size,has been proposed.This study provided guideline to achieve high-temperature stability of nanograin structures of solid solution alloys even for the weakly segregating nanocrystalline systems.

关键词： Substitutional solid solution Grain boundary segregation Thermal stabilization Solute concentration Grain size

Efficient quantum dot sensitized solar cells via improved loading amount management

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Energy & Environment 2023年第1期8卷 213-223页

作者： Wei Wang Yiling Xie Fangfang He Yuan Wang Weinan Xue Yan Li key laboratory for advanced materials Shanghai Key Laboratory of Functional Materials ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China

High light-harvesting efficiency and low interfacial charge transfer loss are essential for the fabrication of high-efficiency quantum dot-based solar cells(QDSCs). Increasing the thickness of mesoporous TiO2films can improve the loading of pre-synthesized QDs on the film and enhance the absorbance of photoanode, but commonly accompanied by the increase in the unfavorable charge recombination due to prolonged electron transmission paths. Herein, we systematically studied the influence of the balance between QD loading and TiO2film thickness on the performance of QDSCs. It is found that the relative thin photoanode prepared by the cationic surfactant-assisted multiple deposition procedure has achieved a high QD loading which is comparable to that of the thick photoanode commonly used. Under AM 1.5G illumination, Zn–Cu–In–Se and Zn–Cu–In–S based QDSCs with optimized 11.8 μm photoanodes show the PCE of 10.03% and 8.53%, respectively, which are comparable to the corresponding highest PCE of Zn–Cu–In–Se and Zn–Cu–In–S QDSCs(9.74% and 8.75%) with over 25.0 μm photoanodes. Similarly, an impressive PCE of 6.14% was obtained for the CdSe based QDSCs with a 4.1 μm photoanode, which is slightly lower than the best PCE(7.05%)of reference CdSe QDSCs with 18.1 μm photoanode.

关键词： Quantum dot sensitized solar cell Photoanode Loading amount Surfactant-assisted deposition

Covalence bridge atomically precise metal nanocluster and metalorganic frameworks for enhanced photostability and photocatalysis

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第1期16卷 1527-1532页

作者： Aimin Yao Yuanxin Du Meng Han Yan Wang Jiashen Hu Qingtao Zhu Hongting Sheng Manzhou Zhu Department of materials Science and Engineering Centre for Atomic Engineering of Advanced MaterialsKey Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Functional Inorganic Material Chemistry of Anhui ProvinceAnhui UniversityHefei 230601China

Metal nanoclusters(NCs)with precise structure and ultrasmall size have attracted great interests in catalysis.However,the poor stability has limited its large-scale use.Herein,we proposed the“covalence bridge”strategy to effectively connect atomically precise metal NCs and metal-organic frameworks.Benefiting from the covalent linkage,the synthesized UiO-66-NH2-Au25(LCys)18 showed outstanding stability after 16 h photocatalysis.Moreover,the covalence bridge created a strong metal-support interaction between the two components and provided an effective charge transport channel and thereby enhanced photocatalytic activity.UiO-66-NH2-Au25(L-Cys)18 displayed an exceptional photocatalytic H2 production rate,which is 21 and 90 times higher than that of UiO-66-NH2/Au25(PET)18(made by physically combination)and bare UiO-66-NH2,respectively.Thermodynamic and kinetic studies demonstrated that UiO-66-NH2-Au25(L-Cys)18 exhibited higher charge transfer efficiency,lower overpotential of water reduction and activation energy barrier compared with its counterparts.

关键词： atomically precise nanoclusters metal-organic frameworks covalent binding photostability photocatalytic hydrogen production

Rationally construction of atomic-precise interfacial charge transfer channel and strong build-in electric field in nanocluster-based Zscheme heterojunctions with enhanced photocatalytic hydrogen production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5002-5010页

作者： Qingtao Zhu Honglei Shen Chao Han Liu Huang Yanting Zhou Yuanxin Du Xi Kang Manzhou Zhu Department of materials Science and Engineering Centre for Atomic Engineering of Advanced MaterialsKey Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Functional Inorganic Material Chemistry of Anhui ProvinceAnhui UniversityHefei 230601China

The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-based heterojunction(Pt1Ag28-BTT/CoP,BTT=1,3,5-benzenetrithiol)with strong internal electric field is constructed via interfacial Co-S bond,which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h^(−1)·g−1 H_(2)production rate,25.77%apparent quantum yield at 420 nm,and~100%activity retention in stability,compared with Pt1Ag28-BDT/CoP(BDT=1,3-benzenedithiol),Ag29-BDT/CoP,and CoP.The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC,wherein,the center Pt single atom doping regulates the band structure of NC to match well with CoP,builds internal electric field,and then drives photogenerated electrons steering;the accurate surface S modification promotes the formation of Co-S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration.This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.

关键词： atomically precise metal nanocluster Z-scheme heterojunction interfacial charge transfer build-in electric field photocatalytic hydrogen production

Surface modification of tungsten oxide by oxygen vacancies for hydrogen adsorption

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2022年第22期117卷 23-35页

作者： Q.Zhang F.W.Tang Z.Zhao Z.R.Nie X.Y.Song Faculty of materials and Manufacturing Key Laboratory of Advanced Functional MaterialsMinistry of Education of ChinaBeijing University of TechnologyBeijing 100124China

A model for describing the adsorption process of hydrogen on surface of tungsten oxide was proposed based on the first-principle calculations. Multiple factors such as type of active surface, adsorption site and distribution of oxygen vacancies were considered to evaluate the hydrogen adsorption capability of tungsten oxide. The adsorption Gibbs free energies, electronic structures and bonding characteristics under various conditions were examined to reveal the influence of oxygen vacancies on the surface. It is found that the capability of hydrogen adsorption of tungsten oxide can be significantly enhanced by adjusting the oxygen vacancy on the outermost layer of certain active surfaces. The modeling predicts that the surface structure stability and gas adsorption ability of tungsten oxide can be simultaneously improved through the formation of W–H bonds. The proposed strategy for moderating surface provides a new approach to obtain excellent gas-sensitive metal oxide materials.

关键词： Metal oxide Gas-sensitive material Surface adsorption Oxygen vacancy First-principles calculation

Uncover the mystery of interfacial interactions in immiscible composites by spectroscopic microscopy:A case study with W-Cu

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2022年第31期126卷 106-115页

作者： Zhi Zhao Fawei Tang Chao Hou Xintao Huang Xiaoyan Song Faculty of materials and Manufacturing Key Laboratory of Advanced Functional MaterialsEducation Ministry of ChinaBeijing University of TechnologyBeijing 100124China

Characterizing immiscible metallic composites with electron microscopy and X-ray spectroscopy is the classic way of obtaining their structural and physical details.Nevertheless,such a combination lacks abil-ity to tell the interfacial interactions at grain boundaries.Here we demonstrate a novel strategy to un-cover the mystery of interfacial interactions in such systems by spectroscopic microscopy.The morpho-logical and spectral data of samples were simultaneously recorded and analyzed,which reveals critical information regarding interfacial electronic modes.Taking W-Cu as a model,we experimentally quanti-fied its connectivity and unambiguously identified conditional bonding between W and Cu.Further,we chemically reconstructed the specific W-Cu boundary that possessed the strongest interactions and inves-tigated its atomic structure.The mechanism of W-Cu bonding was proposed and verified by first-principle calculations.The above methodology holds great promise to serve as a universal approach in achieving in-depth understanding of immiscible composites.

关键词： Metal-matrix composites Interface Physical properties Spectroscopic microscopy Interfacial bonding

Gelation of Hole Transport Layer to Improve the Stability of Perovskite Solar Cells

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第10期15卷 305-316页

作者： Ying Zhang Chenxiao Zhou Lizhi Lin Fengtao Pei Mengqi Xiao Xiaoyan Yang Guizhou Yuan Cheng Zhu Yu Chen Qi Chen Beijing key laboratory of Construction Tailorable advanced functional materials and Green Applications MIIT Key Laboratory for Low‑Dimensional Quantum Structure and DevicesExperimental Center of Advanced MaterialsSchool of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081People’s Republic of China

To achieve high power conversion efficiency(PCE) and long-term stability of perovskite solar cells(PSCs), a hole transport layer(HTL) with persistently high conductivity, good moisture/oxygen barrier ability, and adequate passivation capability is important. To achieve enough conductivity and effective hole extraction, spiro-OMe TAD, one of the most frequently used HTL in optoelectronic devices, often needs chemical doping with a lithium compound(LiTFSI). However, the lithium salt dopant induces crystallization and has a negative impact on the performance and lifetime of the device due to its hygroscopic nature. Here, we provide an easy method for creating a gel by mixing a natural small molecule additive(thioctic acid, TA) with spiro-OMe TAD. We discover that gelation effectively improves the compactness of resultant HTL and prevents moisture and oxygen infiltration. Moreover, the gelation of HTL improves not only the conductivity of spiro-OMe TAD, but also the operational robustness of the devices in the atmospheric environment. In addition, TA passivates the perovskite defects and facilitates the charge transfer from the perovskite layer to HTL. As a consequence, the optimized PSCs based on the gelated HTL exhibit an improved PCE(22.52%) with excellent device stability.

关键词： Perovskite solar cell Hole transport layer Gelation Humidity stability Aggregation of LiTFSI

Reversible Zn stripping/plating achieved by surface thin Sn layer for high-performance aqueous zinc metal batteries

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2022年第22期117卷 72-78页

作者： Bingfeng Cui Yu Gao Xiaopeng Han Wenbin Hu Tianjin key laboratory of Composite and functional materials Key Laboratory of Advanced Ceramics and Machining Technology(Ministry of Education)School of Materials Science and EngineeringTianjin UniversityTianjin 300350China

Aqueous zinc metal batteries (ZMBs) are considered as the most promising candidate for large-scale energy storage system due to their abundant reserves and high safety. To achieve highly stable zinc metalbatteries, it is imperative to inhibit the unavoidable dendrite growth, which leads to the non-uniformzinc deposition and even makes the battery short circuit. Herein, Sn coating is loaded on copper foil(SCF) by a simple electrodeposition to guide the uniform zinc deposition, which not only lowers the zincnucleation overpotential but also promotes the uniform zinc deposition/dissolution. As a result, the Znplated SCF (Zn@SCF) anode presents a low voltage hysteresis of ∼40 mV and a superior stability over270 h in symmetric cells at a current density of 1 mA cm^(−2). Furthermore, the Zn@SCF anode can realizethe improved performance for full cells paired with α-MnO_(2) cathode. This work provides a simple andeffective approach to modify the Zn anode for improved electrochemical performance of ZMBs.

关键词： Tin coatings Uniform zinc deposition Zinc anode Zinc metal batteries