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Single thiolate replacement of metal nanoclusters

science China Chemistry 2024年第2期67卷 523-528页

作者： Ambreen Ambreen Yue Zhou Wanmiao Gu Qing You Liang Fang Guoqing Bian Nan Yan Nan Xia Zhikun Wu Key Laboratory of Materials Physics Anhui Key Laboratory of Nanomaterials and NanotechnologyInstitute of Solid State PhysicsHefei Institutes of Physical Science(HFIPS)Chinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230601China Institute of Physical Science and Information Technology Anhui UniversityHefei230601China

Surface thiolates play important roles in evincing the structures and properties of thiolated metal nanoclusters—one type of recently emerging inorganic-organic hybrids,and thus the thiolate substitution,especially single thiolate substitution,is highly desirable for subtly tailoring the structures and properties of metal ***,such a single-thiolate substituting is challenging,and its influence on the metal-metal and metal-sulfur bonds remains mysterious due to the absence of the singlethiolate-substituted ***,we developed a combined method,concurrently synthesized the single-thiolate-substituted nanocluster and its parent nanocluster,and successfully resolved their structures by single crystal X-ray crystallography,which reveals that the single thiolate substitute has an obvious influence on the metal-metal and metal-sulfur bond lengths although it has no effect on the absorption ***,the metal-metal and metal-sulfur bonds show various thermal extensibility and even the negative thermal expansion phenomena of the Au–S bond were observed in the single-thiolate-substituted *** bond length-related stability was also ***,this study highlights a novel synthesis method and offers novel structural insights and an in-depth structure-property correlation of thiolated metal nanoclusters.

关键词： metal nanoclusters single thiolate replacement thermal expansion stability intercluster interaction

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Recovery of aluminum oxide and iron oxide from aluminum electrolysis iron-rich cover material and preparation of aluminum fluoride

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Environmental science and Pollution Research 2024年第18期31卷 27388-27402页

作者： Lan, Jinghao Yan, Hengwei Liu, Zhanwei Ma, Wenhui Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Kunming650093 China The National Engineering Laboratory for Vacuum Metallurgy Kunming University of Science and Technology Kunming650093 China

In aluminum electrolysis, the iron-rich cover material is formed on the cover material and the steel rod connecting the carbon anode. Due to the high iron content in the iron-rich cover material, it differs from traditional cover material and thus requires harmless recycling and treatment. A process was proposed and used in this study to recovery F, Al, and Fe elements from the iron-rich cover material. This process involved aluminum sulfate solution leaching for fluorine recovery and alkali-acid synergistic leaching for α-Al2O3 and Fe2O3 recovery were obtained. The optimal leaching rates for F, Na, Ca, Fe, and Si were 93.92, 96.25, 94.53, 4.48, and 28.87%, respectively. The leaching solution and leaching residue were obtained. The leaching solution was neutralized to obtain the aluminum hydroxide fluoride hydrate (AHFH, AlF1.5(OH)1.5·(H2O)0.375). AHFH was calcined to form a mixture of AlF3 and Al2O3 with a purity of 96.14%. The overall recovery rate of F in the entire process was 92.36%. Additionally, the leaching residue was sequentially leached with alkali and acid to obtain the acid leach residue α-Al2O3. The pH of the acid-leached solution was adjusted to produce a black-brown precipitate, which was converted to Fe2O3 under a high-temperature calcination, and the recovery rate of Fe in the whole process was 94.54%. Therefore, this study provides a new method for recovering F, Al, and Fe in iron-rich cover material, enabling the utilization of aluminum hazardous waste sources. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.

关键词： Sulfur compounds

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Impact of Quantum Coherence on Inelastic Thermoelectric Devices:From Diode to Transistor

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Chinese Physics Letters 2024年第7期41卷 117-125页

作者：曹蓓韩崇泽郝翔王晨陆金成 Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhou 215009China Department of Physics Zhejiang Normal UniversityJinhua 321004China

We present a study on inelastic thermoelectric devices, wherein charge currents and electronic and phononic heat currents are intricately interconnected. The employment of double quantum dots in conjunction with a phonon reservoir positions them as promising candidates for quantum thermoelectric diodes and transistors. We illustrate that quantum coherence yields significant charge and Seebeck rectification effects. It is worth noting that, while the thermal transistor effect is observable in the linear response regime, especially when phononassisted inelastic processes dominate the transport, quantum coherence does not enhance thermal *** work may provide valuable insights for the optimization of inelastic thermoelectric devices.

关键词： quantum charge Quantum

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Preparing cyclic polymers at high concentrations via self-folding cyclization technique by adjusting the contents of hydrophilic units in linear precursors

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Chinese Chemical Letters 2024年第2期35卷 283-288页

作者： Hao Zha Zuowei Wang Chao Liu Chunyan Hong Department of Polymer Science and Engineering University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China

Cyclic polymers are a class of polymers that feature endless topology,and the synthesis of cyclic polymers has attracted the attention of many ***,cyclic polymers were efficiently constructed by self-folding cyclization technique at high *** poly((oligo(ethylene glycol)acrylate)-co-(dodecyl acrylate))(P(OEGA-co-DDA))precursors with different ratios of hydrophilic and hydrophobic moieties were synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization using a bifunctional chain transfer agent with two anthryl end *** amphiphilic linear precursors underwent the self-folding process to generate polymeric nanoparticles in *** irradiating the aqueous solution of the nanoparticles with 365 nm UV light,cyclic polymers were synthesized successfully via coupling of anthryl *** effects of the ratios of hydrophilic and hydrophobic moieties in linear P(OEGA-co-DDA)copolymers and polymer concentration on the purity of the obtained cyclic polymers were explored in detail via ^(1)H nuclear magnetic resonance(^(1)H NMR),dynamic light scattering(DLS),UV‒visible(vis)analysis,three-detection size exclusion chromatography(TD-SEC)and transmission electron microscopy(TEM).It was found that by adjusting the content of the hydrophilic segments in linear precursors,single chain polymeric nanoparticles(SCPNs)can be generated at high polymer ***,cyclic polymers with high purity can be constructed *** method overcomes the limitation of traditional ring-closure method,which is typically conducted in highly dilute conditions,providing an efficient method for the scalable preparation of cyclic polymers.

关键词： Cyclic polymers Self-folding cyclization technique Single chain polymeric nanoparticles RAFT polymerization Direct visualization

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Study on the theoretical and mechanism of CaF_(2)-catalyzed vacuum carbothermal reduction of MgO

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Journal of Magnesium and Alloys 2025年第2期13卷 731-745页

作者： Tingzhuang Ma Bin Yang Yang Tian Neng Xiong Baoqiang Xu Guozheng Zha Rong Yu Dong Liang Lipeng Wang Dong Wang Key Laboratory for Nonferrous Vacuum Metallurgy of Yunnan Province Kunming University of Science and TechnologyKunming 650093China Yunnan province Engineering Research Center of Aluminium Industry Kunming University of Science and TechnologyKunming 650093China National Engineering Research Center of Vacuum Metallurgy Kunming University of Science and TechnologyKunming 650093China Faculty of Metallurgical and Energy Engineering Kunming University of Science and TechnologyKunming 650093China IME Institute of Process Metallurgy and Metal Recycling RWTH Aachen UniversityAachen 52056Germany

The increasing demand for magnesium as a next-generation structural material highlights the significance of incorporating CaF_(2)as a catalyst to enhance the efficiency of vacuum carbothermal reduction of magnesium(VCTRM).This study investigates the thermodynamic theory and catalytic mechanism of CaF_(2)in the VCTRM *** reduction experiments and molecular dynamics simulations were conducted to gain a comprehensive understanding of the *** calculations indicate that in vacuum carbothermal reduction,the primary reaction occurs between MgO and *** shows that CaF_(2)'s catalytic action primarily involves F^(-),Ca^(2+),and melt *** experiments demonstrate that the addition of CaF_(2)significantly increases the reduction ***,the mass loss rate increases with both the quantity of CaF_(2)added and the holding time,stabilizing at additions over 5%.Experiments conducted at temperatures above the melting point of CaF_(2)exhibited a pronounced catalytic *** resultant magnesium showed optimal structure and crystallization,with a purity of 87.84%.Notably,while CaF_(2)remained in the residue,it was not detected in the condensate,confirming its catalytic *** dynamics simulations revealed that molten CaF_(2)sabotages the structure of magnesium oxide,with F^(-)dispersing onto the surface of MgO,thus enhancing the reaction between MgO and C to form ***,no chemical reaction was observed between C,MgO,and CaF_(2).The occurrence of the carbothermal reduction reaction at high temperatures depends on the concentration of the reducing agent C,with CaF_(2)influencing the reaction *** research elucidates the theoretical and mechanistic foundations of CaF_(2)-catalyzed VCTRM,aligning with the green energy-saving concept and significantly advancing the green and efficient VCTRM process.

关键词： vacuum carbothermal reduction of magnesium Thermodynamic theory Catalytic mechanism Molecular dynamics simulation Magnesium Green energy-saving

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Constraining the Earth-mass Primordial Black Hole Mergers Model of the Non-repeating FRBs Using the First CHIME/FRB Catalog

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Research in Astronomy and Astrophysics 2024年第9期24卷 76-82页

作者： Min Meng Qiu-Ju Huang Can-Min Deng Guangxi Key Laboratory for Relativistic Astrophysics School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

In this paper,we upgrade the constraints for the Earth-mass primordial black hole mergers model based on the first Canadian Hydrogen Intensity Mapping Experiment(CHIME)/fast radio burst(FRB)*** the null hypothesis that the observed non-repeating FRBs originate from Earth-mass primordial black hole mergers,we find that how the charges were distributed in the primordial black hole population is well described by a double powerlaw function with typical charge value of law function with typical charge value of q_(c)/10^(-5)=1.60_(-0.28)^(+0.28),where the power-law index α_(1)=2.33_(-0.18)^(+0.15) for q

关键词： black hole physics (stars:)gamma ray burst:general (cosmology:)dark matter

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Optimizing large optical contrast in Ge-Se-Te films via high-throughput method

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Progress in Natural science:Materials International 2025年第1期35卷 222-228页

作者： Qiqi Chen Guoxiang Wang Zijun Liu Yixiao Gao Chenjie Gu Tiefeng Xu Xiang Shen Yimin Chen Laboratory of Infrared Material and Devices & Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province Advanced Technology Research InstituteNingbo University Department of Microelectronic Science and Engineering School of Physical Science and Technology Ningbo University Ningbo Solartrum Co.Ltd.

Chalcogenide phase-change materials（PCMs） have attracted great attentions due to their potential applications in reconfigurable photonic devices. The Ge2Sb2Te5and GeTe PCMs exhibit significant difference in refractive index（Δn） between amorphous and crystalline states, but they suffer from high optical loss. The binary Sb2S3and Sb2Se3PCMs, however, show low optical loss but small Δn. This encourages us to develop the novel materials,which are desired to combine large Δn and low optical loss. Instead of traditional trial-and-error screening method, we here used an efficient high-throughput method to optimize the PCMs' candidates for reconfigurable photonic devices in Ge-Se-Te chalcogenides. The crystallization temperature and difference in optical bandgap were detected, and then the component of Ge25Se7Te68, which also exhibits ultralow optical loss of 1.2 × 10-6（in amorphous state） and large Δn of 1.32 at 1550 nm, was optimized. This Te-rich Ge-Se-Te film can be a candidate for the applications of programmable reconfigurable photonic circuits.

关键词： Chalcogenide phase-change films High-throughput Reconfigurable photonics Refractive index

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Microstructure dependence of electrochemical corrosion resistance for rapidly solidified Ti_(50)Al_(48)Mo_(2)alloy

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Journal of Materials science & technology 2024年第18期185卷 58-68页

作者： Chonghao Sun Ruilin Xiao Kelun Liu Ying Ruan Bingbo Wei MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions School of Physical Science and TechnologyNorthwestern

The rapid solidification of undercooled liquid Ti_(50)Al_(48)Mo_(2)alloy was achieved by the electromagnetic lev-itation(EML)*** small and medium undercoolings,primary(βTi)dendrite reacted with sur-rounding liquid to drive a peritectic transformation into the(αTi)*** solutal Mo and Al segrega-tions were located within the dendrite center and the grain boundary during peritectic transformation,consequently B2 phase in the dendrite center andγphase at the grain boundary *** under-cooling exceeded 253 K,the peritectic transformation was completely inhibited,and the formation of the B2 phase andγphase was completely *** ultrafine eutectoid structure was formed and a complete solute trapping effect was *** solute distribution facilitated the forma-tion of thicker passivation film with lower defect density and higher film resistance on the alloy ***,this weakened micro-galvanic effect reduced the susceptibility to pitting corrosion,and conse-quently the corrosion resistance of the alloy was improved.

关键词： Ti-Al based alloys Electromagnetic levitation technique Undercooling Rapid solidification Passivation film

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Room-temperature ferrimagnetism and size-modulated electronic structures in two-dimensional cluster-based metal-organic frameworks

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science China Chemistry 2024年第4期67卷 1334-1340页

作者： Jing Cheng Xingxing Li Jinlong Yang Key Laboratory of Precision and Intelligent Chemistry University of Science and Technology of ChinaHefei 230026China Department of Chemical Physics University of Science and Technology of ChinaHefei 230026China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei 230026China Hefei National Laboratory University of Science and Technology of ChinaHefei 230088China

Cluster-assembled materials have attracted particular attention for their complex hierarchical structures and unique ***,the majority of cluster-based assemblies developed so far are either non-magnetic or only exhibit magnetic ordering with a relatively low Curie temperature,limiting their applications in ***,two-dimensional(2D)cluster-assembled materials with room-temperature magnetism remain highly *** this purpose,based on first principles calculations,we design a series of thermodynamically stable 2D cluster-based metal-organic frameworks(MOFs)Fe_(n)-(pyz)(n=1-6)by utilizing Fenmetal clusters as nodes and nitrogen-containing pyrazine ligands as organic *** 2D cluster-based MOFs exhibit robust ferrimagnetic ordering due to the strong d-p direct exchange interaction between d-electron spin of Fe_(n)(n=1-6)clusters and charge transfer-induced p-electron spin of pyrazine *** particular,the ferrimagnetic Curie temperatures are well above room temperature(up to 836 K).Additionally,altering the size of Fe_(n)clusters in Fe_(n)-(pyz)(n=1-6)MOFs results in diverse functional spintronic properties,including bipolar magnetic semiconductors,half semiconductors and Dirac half ***,these 2D assembled MOFs possess sizable magnetic anisotropy energies,up to 9.16 me V per formula.

关键词： metal-organic framework two-dimensional material half metal bipolar magnetic semiconductor magnet

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Boosting oxygen reduction in acidic media through integration of Pt-Co alloy effect and strong interaction with carbon defects

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Nano Research 2024年第9期17卷 7900-7908页

作者： Nannan Ji Haoyun Sheng Shilong Liu Yangyuan Zhang Hongfei Sun Lingzhi Wei Ziqi Tian Peng Jiang Qianwang Chen Jianwei Su Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid MaterialsAnhui UniversityHefei 230601China Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China Hefei National Laboratory for Physical Science at Microscale Department of Materials Science&EngineeringUniversity of Science and Technology of ChinaHefei 230026China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China

Optimization of Pt atom utilization efficiency is critical for the development of proton-exchange-membrane fuel *** we aim to develop an efficient oxygen reduction reaction(ORR)catalyst with a low Pt content through the concurrent modification of Pt-Co alloy catalysts and carbon *** the present study,ultrafine Pt-Co alloy nanoparticles are successfully synthesized and stabilized by topological carbon defects via adopting the ammonia thermal *** the low Pt loading,the obtained catalyst exhibits an impressive half-wave potential of 0.926 V versus the reversible hydrogen electrode in 0.1 M HClO_(4)***,the durability testing using the timed-current method demonstrates a tiny loss of only 3.6%after 12 *** experimental results and theoretical calculations demonstrate that topological carbon defects significantly enhance the charge transfer processes at the alloy/carbon interface,contributing to the strong electronic metal-support interactions between the Pt-Co alloy nanoparticles and topological carbon *** interactions,along with the alloy effect,play a crucial role in promoting the ORR performance in acidic media.

关键词： electrocatalysis oxygen reduction reaction Pt-Co alloy electronic interaction topological carbon defects

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