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976 nm continuous-wave laser damage of Er:CaF_(2) crystals

High Power Laser science and Engineering 2024年第5期12卷 97-105页

作者： Haiyang Wang Mengxia Wang Zhen Zhang Yuanan Zhao Dawei Li Kun Shuai Hailong Qiu Zhonghan Zhang Liangbi Su Jianda Shao Tianjin Key Laboratory of Functional Crystal Materials Institute of Functional CrystalsTianjin University of TechnologyTianjinChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Laboratory of Thin Film Optics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghaiChina Shanghai Institute of Ceramics Chinese Academy of SciencesShanghaiChina Hangzhou Institute for Advanced Study University of Chinese Academy of SciencesHangzhouChina

Er:CaF_(2) crystals are crucial gain media for producing 3μm mid-infrared (MIR) lasers pumped by 976 nm continuouswave (CW) lasers owing to their low phonon energy and high conversion *** study investigated the damage characteristics and mechanism of Er:CaF_(2) crystals irradiated with a 976 nm CW *** laser-induced damage threshold of Er:CaF_(2) crystals with different Er^(3+) doping levels was tested;the damage morphology consists of a series of regular 70? cracks related to the angle of the crystal slip system on the surface.A finite-element model was used to calculate the temperature and stress fields of the *** results indicated that the damage can be attributed to surface tensile stresses caused by the temperature gradient,and crystals with higher doping concentrations were more susceptible to damage owing to stronger light *** findings provide valuable insights into the development of high-power MIR lasers.

关键词： continuous-wave laser-induced damage Er:CaF_(2) mid-infrared laser thermal stress

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Precipitation mechanism and microstructural evolution of Al2O3/ZrO2(CeO2) solid solution powders consolidated by spark plasma sintering

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Journal of Materials science & technology 2020年第6期41卷 149-158页

作者： Wanjun Yu Yongting Zheng Yongdong Yu National Key Laboratory of Science and Technology on Advanced Composites in Special Environments and Center for Composite Materials and Structures Harbin Institute of TechnologyHarbin 150080China

It is difficult to synthesize Al2O3/ZrO2 solid solution because of its low solubility under equilibrium solidification *** this work,a new combustion synthesis combined with water atomization(CS-WA)method was developed to prepare supersaturated Al2O3/ZrO2(CeO2)solid solution *** ultrahigh cooling rate supplied by CS-WA greatly extends solid solubility of Al2O3 in *** precipitation mechanism of solid solution was investigated by systematic heat *** initial temperature of the metastable phase decomposed into Al2O3 and ZrO2 is 1050℃,and it could be completely precipitated at 1400℃in 0.5 *** precipitated ZrO2 particles were uniformly dispersed in Al2O3 matrix and grew into submicron scale at annealing temperature of 1450℃.Subsequently,together with detailed microstructure,phase composition,as well as mechanical properties were collaboratively outlined to discuss spark plasma sintering(SPS)*** solid solution precipitated Al2O3 matrix and ZrO2 particles during the SPS *** ZrO2 particles were uniformly distributed within Al2O3 matrix,while the residuary ZrO2 located at the grain boundaries and formed special transgranular/intergranular *** average size of nanoscale transgranular ZrO2 particles was only^11.5 *** compact ZrO2 toughened Al2O3 nano ceramic(N-ZTA)exhibits excellent mechanical *** work provides a guidance to produce nanostructured ZTA with high performance.

关键词： Solid solution Precipitation Spark plasma sintering ZTA Transgranular/intergranular structure

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Unleash electron transfer in C–H functionalization by mesoporous carbon-supported palladium interstitial catalysts

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National science Review 2021年第4期8卷 154-166页

作者： Xiaorui Zhao Yueqiang Cao Linlin Duan Ruoou Yang Zheng Jiang Chao Tian Shangjun Chen Xuezhi Duan De Chen Ying Wan Key Laboratory of Resource Chemistry of Ministry of Education Shanghai Key Laboratory of Rare Earth Functional MaterialsDepartment of Chemistry Shanghai Normal University State Key Laboratory of Chemical Engineering East China University of Science and Technology Shanghai Synchrotron Radiation Facility Zhangjiang National Lab Shanghai Advanced Research Institute Chinese Academy of Sciences Department of Chemical Engineering Norwegian University of Science and Technology

The functionalization of otherwise unreactive C–H bonds adds a new dimension to synthetic chemistry,yielding useful molecules for a range of applications. Arylation has emerged as an increasingly viable strategy for functionalization of heteroarenes which constitute an important class of structural moieties for organic materials. However, direct bisarylation of heteroarenes to enable aryl-heteroaryl-aryl bond formation remains a formidable challenge, due to the strong coordination between heteroatom of N or S and transitional metals. Here we report Pd interstitial nanocatalysts supported on ordered mesoporous carbon as catalysts for a direct and highly efficient bisarylation method for five-membered heteroarenes that allows for green and mild reaction conditions. Notably, in the absence of any base, ligands and phase transfer agents, high activity(turn-over frequency, TOF, up to 107 h-1) and selectivity（>99%） for the2,5-bisarylation of five-membered heteroarenes are achieved in water. A combination of characterization reveals that the remarkable catalytic reactivity here is attributable to the parallel adsorption of heteroarene over Pd clusters, which breaks the barrier to electron transfer in traditional homogenous catalysis and creates dual electrophilic sites for aryl radicals and adsorbate at C2 and C5 positions. The d-band filling at Pd sites shows a linear relationship with activation entropy and catalytic activity. The ordered mesopores facilitate the absence of a mass transfer effect. These findings suggest alternative synthesis pathways for the design, synthesis and understanding of a large number of organic chemicals by ordered mesoporous carbon supported palladium catalysts.

关键词： palladium interstitial catalyst ordered mesoporous carbon direct bisarylation multi-site electron transfer d-charge gain

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Understanding Bridging Sites and Accelerating Quantum Efficiency for Photocatalytic CO_(2) Reduction

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Nano-Micro Letters 2024年第1期16卷 68-84页

作者： Kangwang Wang Zhuofeng Hu Peifeng Yu Alina M.Balu Kuan Li Longfu Li Lingyong Zeng Chao Zhang Rafael Luque Kai Yan Huixia Luo School of Materials Science and Engineering State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesKey Lab of Polymer Composite and Functional MaterialsSun Yat-Sen UniversityNo.135Xingang Xi RoadGuangzhou 510275People’s Republic of China School of Environmental Science and Engineering Sun Yat-Sen UniversityNo.135Xingang Xi RoadGuangzhou 510275People’s Republic of China Departamento de Química Orgánica Universidad de CórdobaCampus Universitario de RabanalesEdificio Marie Curie(C3)14014 CórdobaSpain Center for Refining and Advanced Chemicals King Fahd University of Petroleum and Minerals31261 DhahranSaudi Arabia Universidad ECOTEC Km 13.5 SamborondónEC092302 SamborondónEcuador

We report a novel double-shelled nanoboxes photocatalyst architecture with tailored interfaces that accelerate quantum efficiency for photocatalytic CO_(2) reduction reaction(CO_(2)RR)via Mo–S bridging bonds sites in S_(v)–In_(2)S_(3)@2H–MoTe_(2).The X-ray absorption near-edge structure shows that the formation of S_(v)–In_(2)S_(3)@2H–MoTe_(2) adjusts the coordination environment via interface engineering and forms Mo–S polarized sites at the *** interfacial dynamics and catalytic behavior are clearly revealed by ultrafast femtosecond transient absorption,time-resolved,and in situ diffuse reflectance–Infrared Fourier transform spectroscopy.A tunable electronic structure through steric interaction of Mo–S bridging bonds induces a 1.7-fold enhancement in S_(v)–In_(2)S_(3)@2H–MoTe_(2)(5)photogenerated carrier concentration relative to pristine S_(v)–In_(2)S_(3).Benefiting from lower carrier transport activation energy,an internal quantum efficiency of 94.01%at 380 nm was used for photocatalytic CO_(2)*** study proposes a new strategy to design photocatalyst through bridging sites to adjust the selectivity of photocatalytic CO_(2)RR.

关键词： Quantum efficiency Electronic structure Steric interaction Bridging sites CO_(2)reduction

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Donor strategy for promoting nonradiative decay to achieve an efficient photothermal therapy for treating cancer

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science China Chemistry 2021年第9期64卷 1530-1539页

作者： Fei Ren Zeshun Li Kai Li Xiaoyan Zheng Jianbing Shi Chen Zhang Heng Guo Bin Tong Lei Xi Zhengxu Cai Yuping Dong Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green Applications School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing100081China Shenzhen Key Laboratory of Smart Healthcare Engineering Department of Biomedical EngineeringSouthern University of Science and Technology(SUSTech)Shenzhen518055China Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials Key Laboratory of Cluster Science of Ministry of EducationSchool of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing100081China

Photothermal therapy(PTT)is emerging as an effective treatment for superficial carcinoma.A key challenge to the effectiveness of PTT is to develop photosensitizers with high photothermal conversion *** to address this challenge,we develop a series of multi-arylpyrrole derivatives with different donors that contain different multi-rotor structures to explore highly efficient PTT *** these multi-arylpyrrole derivatives,MAP4-FE nanoparticles with a small size of their donor groups and better-donating ability exhibit a high photothermal conversion efficiency(up to 72%)when they are encapsulated by an amphiphilic *** a result,the MAP4-FE nanoparticles have shown satisfactory PTTeffects on in vivo tumor eradication under the guidance of photoacoustic *** findings of this study provide significant insights for the development of high-efficiency PTT photosensitizers for cancer treatment by making full use of the nonradiative decay of small size donors as rotors.

关键词： aggregation-induced emission multi-arylpyrroles photothermal therapy photoacoustic imaging

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单团簇催化剂在乙炔半加氢反应中的优异反应性

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science China Materials 2023年第10期66卷 3912-3921页

作者：赵姝汤妍于小虎李隽 Institute of Advanced Battery Materials and Devices Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China Key Laboratory of Advanced Functional Materials Ministry of EducationBeijing University of TechnologyBeijing 100124China Department of Chemistry and Engineering Research Center of Advanced Rare-Earth Materials of Ministry of Education Tsinghua UniversityBeijing 100084China Shaanxi Key Laboratory of Catalysis School of Chemical&Environment SciencesShaanxi University of TechnologyHanzhong 723000China Department of Chemistry Southern University of Science and TechnologyShenzhen 518055China

载体上孤立的Pd原子作为乙炔半加氢反应的催化活性位点,由于具有独特的反应性和高效的金属利用率而备受关注.特别是在金属氧化物表面的不同位点掺杂Pd单原子,可以通过调节其局部配位环境来调控其电子和催化性能.本文采用密度泛函理论计... 详细信息

载体上孤立的Pd原子作为乙炔半加氢反应的催化活性位点,由于具有独特的反应性和高效的金属利用率而备受关注.特别是在金属氧化物表面的不同位点掺杂Pd单原子,可以通过调节其局部配位环境来调控其电子和催化性能.本文采用密度泛函理论计算,研究了TiO_(2)负载Pd单原子的局域配位环境对Pd_(1)/TiO_(2)催化剂上乙炔半加氢反应的活性和选择性的影响.综合考虑反应活性和选择性,发现具有负电荷Pd^(δ-)位点的Pd_(1)Ti_(3)/TiO_(2)四原子单团簇催化剂展现出优异的催化性能.此外,活性和选择性与表面性质如d-带中心指数和表面功函数等密切相关.本文为未来设计可还原氧化物载体上的高效单团簇催化剂以用于类似的多相催化反应提供了理论参考.

关键词： acetylene semi-hydrogenation single-cluster catalysts(SCCs) TiO_(2) DFT

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Defective Nano-Structure Regulating C-F Bond for Lithium/Fluorinated Carbon Batteries with Dual High-Performance

SSRN

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SSRN 2022年

作者： Kong, Lingchen Li, Yu Peng, Cong Sun, Lidong Wang, Kai Feng, Wei School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Tianjin University Tianjin300350 China Tianjin Key Laboratory of Composite and Functional Materials Tianjin300354 China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of Education Tianjin300354 China Institute of Advanced Technology and Equipment Beijing University of Chemical Technology Beijing100029 China

Lithium/fluorinated carbon (Li/CFx) batteries show significant potential owing to high energy density and excellent long-term storage performance. However, restricted to the mutual restriction of fluorine carbon ratio and conductivity, the high energy density and power density cannot be achieved simultaneously. Herein, fluorinated honeycomb N-doped graphene (F-HNG) with conductive C-F bond is regulated by structural and heteroatomic defects, which is fabricated by nanoscale etching, NH3 treatment and gas phase fluorination. The unique pore and edge structures provide smooth channels and storage sites for Li+ migration, while N atom with more electronegativity further regulate the charge distribution of the carbon skeleton. F-HNG deliver a maximum energy density of 2595.47 Wh kg-1, associated with the unprecedented power density of 73.203 kW kg-1 at an ultrahigh rate of 50 C. Li/F-HNG pouch cell achieves a superior power density of 5.644 kW kg-1 with open circuit voltage up to 3.66 V. In-depth density functional theory (DFT) calculations reveal that synergistic effect of porosity and N-doping regulates its C-F bond configuration, thermodynamic parameters, and ion diffusion pathway. This work indicates that nano-defect engineering and heteroatomic doping provide innovative possible directions for the design of CFx cathodes with dual superior performance. © 2022, The Authors. All rights reserved.

关键词： Doping (additives)

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MOF-derived nitrogen-doped iron–nickel oxide carbon nanotubes as efficient oxygen electrocatalyst for long-life rechargeable zinc–air batteries

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Rare Metals 2023年第10期42卷 3326-3336页

作者： Tao Zhao Yu-Hang Wu Zhi-Rong Song Xue Wang Rui-Lian Yin Hui Xu Hui Cui Xie-Hong Cao Jun-Kuo Gao School of Materials Science and Engineering Institute of Functional Porous MaterialsZhejiang Sci-Tech UniversityHangzhou310018China College of Materials Science and Engineering Pinghu Institute of Advanced MaterialsZhejiang University of TechnologyHangzhou310014China Institute of Optoelectronic Materials and Devices China Jiliang UniversityHangzhou310018China Physics Division Argonne National LaboratoryLemontIL60439USA Department of Chemistry and International Institute for Nanotechnology(IIN) Northwestern UniversityEvanstonIL60208USA

Electrocatalysts with high activities are crucial for highenergy-density Zn-air ***,the sluggish kinetics of oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)on the electrocatalysts hindered the development of Zn-air ***,a new class of MOF-derived nitrogen-doped carbon nanotubes encapsulated with bimetallic oxide(FeNiO@NCNT)through facile pyrolysis strategy is *** FeNiO@NCNT exhibits high catalytic activities for both OER and ORR.

关键词： nickel catalyst carbon

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Nanocarbon Architecture-Dependent Strengthening and Deformation in Al Matrix composites

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SSRN 2024年

作者： Chen, Xiaofeng Zhao, Dongdong Rong, Xudong Li, Jiajun Zhang, Xiang He, Chunnian Shi, Chunsheng Liu, Enzuo Tao, Jingmei Zhao, Naiqin School of Materials Science and Engineering Tianjin Key Laboratory of Composite and Functional Materials Tianjin University Tianjin300072 China Collaborative Innovation Centre of Chemical Science and Engineering Tianjin300072 China Key Laboratory of Advanced Ceramics and Machining Technology Ministry of Education Tianjin University Tianjin300072 China Faculty of Materials Science and Engineering Kunming University of Science and Technology Kunming650093 China Department of Materials Science and Engineering

The extraordinary strength of inner graphene walls in carbon nanotube (CNT) is barely exerted due to the weak inner-wall shear resistance, which extremely limits its load-bearing capability. To overcome such deficiency, nanocarbon architecture engineering from CNT to graphene nanoribbon (GNR) was performed via longitudinal unzipping of multi-walled CNT, which was utilized to reinforce pure Al. Results show that the activation volume of composites at macroyielding point, evaluated by stress relaxation experiments, monotonically decreases from CNT/Al to GNR/Al, which results in the continuous increase of critical resolved shear stress (CRSS) called for dislocation nucleation/cross-slip at the grain boundaries. Shear-lag model and numerical simulations demonstrate the increased load-transfer effect from CNT/Al to GNR/Al. Meanwhile, the isotropic and kinematic hardening in nanocarbon/Al composites were investigated both by loading-unloading-reloading tests and strain hardening model on basis of dislocation behavior, wherein the effective stress was determined as being larger than back stress in the composites. Detailed analysis further indicates that the nanocarbon architecture from CNT to GNR increases the back stress strengthening due to the enhanced dislocation accumulation at nanocarbon/Al interface. Moreover, as CNT was unfolded to GNR, the failure mode of reinforcements in the composites gradually changed from pull-out to breakage. © 2024, The Authors. All rights reserved.

关键词： Shear flow

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Mean-Field Theory of the Uniaxial Ferroelectric Smectic A Liquid Crystal Phase

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Physical Review Letters 2024年第20期133卷 208101-208101页

作者： Aitor Erkoreka Mingjun Huang Satoshi Aya Josu Martinez-Perdiguero Department of Physics Faculty of Science and Technology University of the Basque Country UPV/EHU Bilbao Spain South China Advanced Institute for Soft Matter Science and Technology (AISMST) School of Molecular Science and Engineering South China University of Technology Guangzhou China and Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices South China University of Technology Guangzhou China

Following the groundbreaking discovery of the ferroelectric nematic liquid crystal phase (NF), a series of closely-related new polar phases have also been found. An especially interesting one is the ferroelectric smectic A phase (SmAF) with spontaneous polarization along the layer normal observed in a few materials of the NF realm. Here, we present a mean-field molecular model that successfully captures the rich phase diagrams experimentally observed in the literature in terms of two parameters. Additionally, we carry out second harmonic generation, X-ray diffraction, and birefringence measurements in a compound exhibiting the SmAF phase to determine the appropriate order parameters and compare with the model predictions.

关键词： Ferroelectric phase transition Ferroelectric liquid crystals Liquid crystals Mean field theory

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