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Effect of lattice defects on the electronic structures and floatability of pyrites

International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1069-1076页

作者： Yong-jun Xian Shu-ming Wen Xiu-ming CHen Jiu-shuai Deng Jian Liu Faculty of Land Resource Engineering Kunming University of Science and TechnologyKunming 650093China National Engineering Laboratory of Vacuum Metallurgy Kunming University of Science and TechnologyKunming 650093China

The electronic structures of three types of lattice defects in pyrites （i.e., As-substituted, Co-substituted, and intercrystalline Au py-rites） were calculated using the density functional theory （DFT）. In addition, their band structures, density of states, and difference charge density were studied. The effect of the three types of lattice defects on the pyrite floatability was explored. The calculated results showed that the band-gaps of pyrites with Co-substitution and intercrystalline Au decreased significantly, which favors the oxidation of xanthate to dix-anthogen and the adsorption of dixanthogen during pyrite flotation. The stability of the pyrites increased in the following order： As-substituted 〈 perfect 〈 Co-substituted 〈 intercrystalline Au. Therefore, As-substituted pyrite is easier to be depressed by intensive oxidi-zation compared to perfect pyrite in a strongly alkaline medium. However, Co-substituted and intercrystalline Au pyrites are more difficult to be depressed compared to perfect pyrite. The analysis of the Mulliken bond population and the electron density difference indicates that the covalence characteristic of the S Fe bond is larger compared to the S S bond in perfect pyrite. In addition, the presence of the three types of lattice defects in the pyrite bulk results in an increase in the covalence level of the S Fe bond and a decrease in the covalence level of the S S bond, which affect the natural floatability of the pyrites.

关键词： pyrites lattice defects density functional theory electronic structure flotation

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Effect of yttrium on catalytic performance of Y-doped TiO_(2) catalysts for propane dehydrogenation

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Journal of Rare Earths 2024年第5期42卷 962-971,I0005页

作者： Liyu Hou Liming Xia Ruipeng Zhou Jianmei Li Renjie Li Zhen Zhao Guimei Yuan Aijun Duan State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang110034China

Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively tuned by doping metal in TiO_(2).Herein,yttrium(Y)-doped titanium dioxide(nY/TiO_(x))catalysts were in-situ synthesized via the coprecipitation method to study the effect of rare earth metal Y doping on the structure of TiO_(2) and the catalytic performance for *** results demonstrate that Ydoped TiO_(2) exhibits higher catalytic activity,propylene selectivity and stability than bare TiO_(2).Full characterizations with X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM),X-ray photoelectron spectroscopy(XPS),infrared spectroscopy of pyridine adsorption(Py-IR),temperature-programmed desorption of ammonia(NH_(3)-TPD),H_(2) temperature-programmed reduction(H_2-TPR),and Raman techniques on these catalysts reveal that Y^(3+)can enter TiO_(2) lattice,and the lattice stability of the catalyst can be enhanced by replacing Ti^(4+)to form Y-O-Ti ***,the introduction of an appropriate amount of Y can obviously promote the PDH reaction by adjusting the acidity of the catalyst,improving the release capacity of TiO_(2) lattice oxygen and increasing the formation of active ***,excessive Y doping will lead to pore clogging,and the exposure of active sites will be reduced,resulting in the degradation of catalytic performance.

关键词： Propane dehydrogenation Anatase lattice defects Coordinatively unsaturated Ti cations Oxygen vacancy Rare earths

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Metal-organic decomposition growth of thin film metastable perovskite nickelates with kinetically improved quantum transitions

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International Journal of Minerals,Metallurgy and Materials 2023年第12期30卷 2441-2450页

作者： Haiyan Li Yuzhao Wang Fanqi Meng Wei Mao Xingzhong Cao Yi Bian Hao Zhang Yong Jiang Nuofu Chen Jikun Chen Beijing Advanced Innovation Center for Materials Genome Engineering School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Renewable Energy North China Electric Power UniversityBeijing 102206China School of Materials Science and Engineering Peking UniversityBeijing 100871China School of Engineering The University of Tokyo2-11-16 YayoiBunkyo-kuTokyo 113-0032Japan Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China

The multiple quantum transitions within d-band correlation oxides such as rare-earth nickelates(RENiO_(3))triggered by critical temperatures and/or hydrogenation opened up a new paradigm for correlated electronics applications,*** electric field sensor,bio-sensor,and neuron synapse logical ***,these applications are obstructed by the present ineffectiveness in the thin film growth of the metastable RENiO_(3)with flexibly adjustable rare-earth compositions and electronic ***,we demonstrate a metal-organic decompositions(MOD)approach that can effectively grow metastable RENiO_(3)covering a large variety of the rare-earth composition without introducing any vacuum *** the previous chemical growths for RENiO_(3)relying on strict interfacial coherency that limit the film thickness,the MOD growth using reactive isooctanoate percussors is tolerant to lattice defects and therefore achieves comparable film thickness to vacuum *** indicated by positron annihilation spectroscopy,the RENiO_(3)grown by MOD exhibit large amount of lattice defects that improves their hydrogen incorporation amount and electron transfers,as demonstrated by the resonant nuclear reaction analysis and near edge X-ray absorption fine structure *** effectively enlarges the magnitude in the resistance regulations in particular for RENiO_(3)with lighter RE,shedding a light on the extrinsic regulation of the hydrogen induced quantum transitions for correlated oxides semiconductors kinetically via defect engineering.

关键词： metal-insulator transition rare earth nickelates lattice defects hydrogen incorporation metal-organic decomposition

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Li^(+)doping induced zero-thermal quenching in Cs_(3)Zn_(6-x-y)B_(9)O_(21):xEu^(3+),yLi^(+)(0≤x≤0.10,0.06≤y≤0.16)

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Journal of Rare Earths 2023年第10期41卷 1478-1486,I0001页

作者： Yuxing Bai Liwei Wu Qilin Cheng Li Wu Yongfa Kong Yi Zhang Jingjun Xu Key Laboratory of Weak-Light Nonlinear Photonics Ministry of EducationSchool of PhysicsNankai UniversityTianjin300071China College of Science Civil Aviation University of ChinaTianjin300300China Institute of Photo-electronic Thin Film Devices and Technology Nankai UniversityTianjin300071China

Thermal stability is a crucial index to assess application value of high-power LEDs,which is related to lattice ***,an effective structure-engineering strategy is proposed to achieve excellent *** the 394 nm excitation,Cs_3Zn_(5.94)B_9O_(21):0.06Eu^(3+)possesses two characteristic emissions peaked at 591 and 612 nm with limited thermal *** introducing Li^(+)ions into the lattice,the sample exhibits high color purity and excellent zero-thermal quenching because the defect contents of the phosphor can be effectively modulated via charge-compensation ***,under the stimulus of high temperature,the corresponding trap levels with a suitable depth(E=1.27 eV)will release electrons to recombine with the luminescent centers,compensating for the energy *** study provides a meaningful guide for optimizing and designing novel functional photoluminescent materials.

关键词： Photoluminescence Charge compensation lattice defects Thermal stability Rare earths

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Halogen chlorine triggered oxygen vacancy-rich Ni(OH)_(2) with enhanced reaction kinetics for pseudocapacitive energy storage

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Journal of Energy Chemistry 2023年第7期82卷 296-306,I0007页

作者： Jiangyu Hao Lijin Yan Liang Luo Qiaohui Liu Youcun Bai Yuying Han Yang Zhou Xuefeng Zou Bin Xiang School of Chemistry and Chemical Engineering Chongqing UniversityChongqing 400044China Analytical and Testing Center Chongqing UniversityChongqing 400044China Guizhou Provincial Key Laboratory of Computational Nano-Material Science Guizhou Education UniversityGuiyang 550018GuizhouChina School of Materials Science and Engineering Institute of Materials Science and DeviceSuzhou University of Science and TechnologySuzhou 215009JiangsuChina

Two-dimensional (2D)Ni(OH)_(2) nanosheets can theoretically expose their active sites of 100%.Whereas,their intrinsic easy accumulation and low conductivity lead to weak and unsustainable reaction ***,we propose a novel halogen chlorine-triggered electrochemical etching strategy to controllably manage the reaction kinetics of 2D Ni(OH)_(2) nanosheets(EE/Cl-Ni(OH)_(2)).It is found that halogen chlorine doping can adjust the interlamellar spacing flexibly and promote the lattice oxygen activation to achieve controlled construction of superficial oxygen defects at the adjustable *** optimal EE/Cl-Ni(OH)_(2) electrode exhibits a high rate capability and excellent specific capacity of 206.9 mA h g^(-1) at 1 A g^(-1) in a three-electrode system,which is more than twice as high as the pristine Ni(OH)_(2).Furthermore,EE/Cl-Ni(OH)_(2) cathode and FeOOH@rGO anode are employed for developing an aqueous Ni-Fe battery with an excellent energy density of 83 W h kg^(-1),a high power density of 17051 W kg^(-1),and robust durability over 20,000 *** strategy exploits a fresh channel for the ingenious fabrication of highefficiency and stable nickel-based deficiency materials for energy storage.

关键词： Ni(OH)_(2) Electrochemical etching lattice defects High energy density Ni-Fe battery

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Catalytic Oxidation of Toluene over Nanorod Manganese Oxides Catalysts: Phase Change Effects

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China Petroleum Processing & Petrochemical Technology 2022年第3期24卷 67-76页

作者： Zhang Xuejun Zhang Zhuofu Song Zhongxian Wu Yinghan Liu Wei Liu Zepeng Liu Chunyu Zhu Xinfeng College of Environmental and Safety Engineering Shenyang University of Chemical TechnologyShenyang 110142 Faculty of Environmental and Municipal Engineering Henan Key Laboratory of Water Pollution Control and Rehabilitation TechnologyPingdingshan Key Laboratory of Carbon Emission Reduction and Complex Air Pollution Control TechnologyHenan University of Urban ConstructionPingdingshan 467036

Four manganese oxide (MnO_(x)) catalysts with different phases were prepared via a hydrothermal method, and the toluene oxidation over the four manganese dioxide (MnO_(x)) catalysts was studied. Among the catalysts, δ-MnO_(2) exhibits the best performance, excellent stability, and reusability. Moreover, δ-MnO_(2) possesses the highest specific surface area, with more exposed active sites compared to the other catalysts with which to make contact with toluene, leading to it exhibiting excellent activity. Furthermore, δ-MnO_(2) shows more lattice defects, Mn^(3+)/(Mn^(3+) + Mn^(4+)), oxygen vacancies, and surface adsorbed oxygen than the other catalysts, resulting in its excellent redox properties and catalytic performance. In addition, oxygen molecules adsorb on the oxygen vacancies of δ-MnO_(2), which are beneficial to the adsorption and oxidation of toluene, with benzyl alcohol, benzaldehyde, benzoic acid, and benzoic acid ester detected as specific intermediate products.

关键词： Catalytic oxidation MnOx catalysts lattice defects Mn^(3+)/(Mn^(3+)+Mn^(4+))

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Gas-phase hydrogenation influence on defect behavior in titanium-based hydrogen-storage material

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Progress in Natural Science:Materials International 2017年第1期27卷 105-111页

作者： Roman S.Laptev Viktor N.Kudiiarov Yuri S.Bordulev Andrey A.Mikhaylov Andrey M.Lider Department of General Physics Institute of Physics and Technology National Research Tomsk Polytechnic University

Titanium and its alloys are promising materials for hydrogen storage. However, hydrogen penetration accompanies the exploitation of hydrogen storage alloys. In particular, hydrogen penetration and accumulation in titanium alloys changes their mechanical properties. Therefore, the research works of such materials are mainly focused on improving the reversibility of hydrogen absorption-liberation processes, increasing the thermodynamic characteristics of the alloys, and augmenting their hydrogen storage capacity. In the process of hydrogenation-dehydrogenation, the formed defects both significantly reduce hydrogen storage capacity and can also be used to create effective traps for hydrogen. Therefore, the investigation of hydrogen interaction with structural defects in titanium and its alloys is very important. The present work, the hydrogen-induced formation of defects in the alloys of commercially pure titanium under temperature gas-phase hydrogenation（873 K） has studied by positron lifetime spectroscopy and Doppler broadening spectroscopy. Based on the evolution of positron annihilation parameters τ_f, τd, their corresponding intensities If, Idand relative changes of parameters S/S0and W/W0, the peculiarities of hydrogen interaction with titanium lattice defects were investigated in a wide range of hydrogen concentrations from 0.8at% to 32.0at%.

关键词： Titanium Hydrogen lattice defects Positron annihilation Positron lifetime Doppler broadening

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Stable hetero-metal doped Co-based catalysts prepared by electrodeposition method for low temperature combustion of toluene

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Carbon Resources Conversion 2020年第1期3卷 95-103页

作者： Jing Wang Peifen Wang Qiang Zhao Jin Shi Tao Yu Xiao Du Xiaogang Hao Abuliti Abudula Guoqing Guan Graduate School of Science and Technology Hirosaki University1-BunkyochoHirosaki 036-8560AomoriJapan Energy Conversion Engineering Laboratory Institute of Regional Innovation(IRI)Hirosaki University2-1-3 MatsubaraAomori 030-0813Japan School of Mechanical Engineering Shanghai Jiaotong University800 Dongchuan RD.Minhang DistrictShanghai 200240China Department of Chemical Engineering Taiyuan University of TechnologyTaiyuanShanxi 030024People’s Republic of China

A series of hetero-metal(Ni,Mn,and Cu)doped Co-based catalysts were prepared by a unipolar pulse electro-deposition(UPED)method and applied for the catalytic combustion of *** is found that hetero-metal doping significantly influenced the morphology and surface elemental compositions of Co-based catalysts,and the increase in the contents of Ni and Mn elements made a negative influence on the catalyst structure.H_(2)-TPR and O_(2)-TPD analysis results suggested that the hetero-metal doping enhanced the low temperature reducibility and resulted in the formation of lattice defects,which were favorable to generate more easily reducible species and facilitate the oxygen mobility,thereby improved the performance for the catalytic combustion of ***,the Co-Cu/NF catalyst performed the best catalytic activity with the lowest toluene conversion temperature of T90 at 248℃,which should be contributed by its low-temperature reducibility,increased surface and lattice oxygen species,and high content of active Co^(3+)species promoted by the interaction of the mixed metal ***,the Co-Cu/NF also performed excellent catalytic stability and high selectivity to CO_(2) in the presence and absence of water vapor for the catalytic combustion of toluene for a long term.

关键词： Toluene Catalytic combustion Hetero-metal doping lattice defects Excellent stability high CO_(2)selectivity

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Recent Advances on Preparation Method of Ti-Based Hydrogen Storage Alloy

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Journal of Materials Science and Chemical Engineering 2020年第12期8卷 18-38页

作者： Lina Liang Feng Wang Maohua Rong Zhongmin Wang Songtao Yang Jiang Wang Huaiying Zhou Guangxi Key Laboratory of Information Materials School of Materials Science and Engineering Guilin University of Electronic Technology Guilin China

Ti-based hydrogen storage alloy is one of the most common solid-state hydrogen storage materials due to its high hydrogen absorption capacity, low dehydrogenation temperature and rich resources. This paper mainly presents the influence of several different preparation methods of Ti-based hydrogen storage alloys on the hydrogen storage performance including traditional preparation methods (smelting, rapid quenching and mechanical alloying) and novel methods by plastic deformation (cold rolling, equal channel angular pressing and high-pressure torsion). The microstructure analysis and hydrogen storage properties of Ti-based alloy are summarized thoroughly corresponding with the preparation processes mentioned above. It was found that slight introduction of lattice defects including dislocation, grain boundary, sub-grain boundary and cracks by severe plastic deformation (SPD) was beneficial to improve the hydriding/dehydriding kinetic characteristic. However, the nonuniform composition and residual stress of the alloy may be caused by SPD, which is not conducive to the improvement of hydrogen storage capacity. In the future, it would be expected that new methods and technologies combined with dopant and modification are applied to Ti-based hydrogen storage alloys to make breakthroughs in practical application.

关键词： Ti-Based Alloy Preparation Methods Hydrogen Storage Performance Severe Plastic Deformation lattice defects

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Harness Cross Relaxation to Modulate the Multiplexed Upconversion Emissions in Lanthanide Nanoparticles

Harness Cross Relaxation to Modulate the Multiplexed Upconve...

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中国化学会第二届全国光功能材料青年学者研讨会

作者：张燕黄金钊张婉枚高尚邦杨祥良华中科技大学生命科学与技术学院

Lanthanide upconversion nanoparticles（UCNPs）, owing to their large anti-Stokes shift, deep penetration ability, high signal-to-noise ratio, and excellent photostability, are emerging optical agents attractive in biomedical field inlcuding optical imaging-guided bioimaging, therapeutics, anticounterfeiting, and solar cell ***, the low quantum efficiency of UCNPs emission poses a significant constrain to their practical applications. One of the most important reasons lies in the pronounced cross relaxation effect at high doping level of the activators, which restricts the amount of lanthanide emitters to be low. As such, strategies to harness the cross relaxation to enhance and modulate the upconversion emissions are of great importance. In this talk, I will demonstrate the strategy of how to achieve superbright-luminescence within ultrasmall size. Moreover, I will also elaborate on how to utilize the inert epitaxial growth shell, a traditional tool to enhance the brightness of the UCNPs, to achieve the near-infrared II（NIR-II） excited multiplexing emissions tailoring. Finally, their bio-application in the UCNP enabled near infrared-optogenetic manipulation of motor circuit will be discussed in detail.

关键词： lanthanide upconversion nanoparticles core-shell structure lattice defects nano-photomedicine

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