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crystal phase-controlled growth of PtCu and PtCo alloys on 4H Au nanoribbons for electrocatalytic ethanol oxidation reaction

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Nano Research 2020年第7期13卷 1970-1975页

作者： Jie Wang Jian Zhang Guigao Liu Chongyi Ling Bo Chen Jingtao Huang Xiaozhi Liu Bing Li An-Liang Wang Zhaoning Hu Ming Zhou Ye Chen Hongfei Cheng Jiawei Liu Zhanxi Fan Nailiang Yang Chaoliang Tan Lin Gu Jinlan Wang Hua Zhang Department of Chemistry City University of Hong KongHong KongChina Center for Programmable Materials School of Materials Science and EngineeringNanyang Technological University50 Nanyang AvenueSingapore 639798Singapore School of Physics Southeast UniversityNanjing 211189China Institute of Physics Beijing National Laboratory for Condensed Matter PhysicsChinese Academy of SciencesBeijing 100190China Institute of Materials Research and Engineering(IMRE) Agency for Science Technology and Research(A*STAR)Singapore 138634Singapore Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM) City University of Hong KongHong KongChina

crystal phase can greatly affect the physicochemical properties and applications of nanomaterials.However,it stil remains a great challenge to synthesize nanostructures with the same composition and morphology but different phases in order to explore the phase-dependent properties and applications.Herein,we report the crystal phase-controlled synthesis of PtCu alloy shells on 4H Au nanoribbons(NRBs),referred to as 4H-Au NRBs,to form the 4H-Au@PtCu core-shell NRBs.By tuning the thickness of PtCu,4H-PtCu and face-centered cubic(cc)phase PICu(cc-PtCu)alloy shells are successtully grown on the 4H-Au NRB cores.This thickness-dependent phase-controlled growth strategy can also be used to grow PtCo alloys with 4H or fcc phase on 4H-Au NRBs.Significantly,when used as electrocatalysts for the ethanol oxidation reaction(EOR)in alkaline media,the 4H-Au@4H-PtCu NRBs show much better EOR performance than the 4H-Au@fcc-PtCu NRBs,and both of them possess superior performance compared to the commercial Pt black.Our study provides a strategy on phase-contolled synthesis of nanomaterials used for crystal phase-dependent applications.

关键词： crystal phase 4H hexagonal face-ce ntered cubic ethanol oxidation reaction phase engineering of nanomaterials

Effects of Additive AlCl_3 on crystal phase, Particle Size and Microstructural Parameters of Nanocrystalline TiO_2 Prepared by HF-PCVD

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Journal of Materials Science & Technology 2004年第6期20卷 641-643页

作者： HaipingXU YanpingSUN XinmouCHEN DepartmentofChemicalEngineering TalyuanUniversityofTechnologyTalvuan030024China XinmouNewTechniqueCorporation ShijiazhuangEconomicDevelopmentZoneShijiazhuang050091China

Nanocrystalline TiO2 was prepared by high frequency plasma chemical vapor deposition (HF-PCVD). The effects of additive AlCl3 on crystal phase, particle size and microstructurai parameters of TiO2 nanocrystallites were investigated by X-ray diffraction(XRD) and transmission electron microscopy (TEM). The nanocrystallites obtained experimentally are mixture of anatase and rutile, the uniform diameters of particles are about 30 nm. The phase transformation from anatase to rutile was accelerated by AlCl3, and rutile content is increased from 26.7 wt pct to 53.6 wt pct with increasing of addition of AlCl3 from 0.0 wt pct to 5.0 wt pct. The particle size is reduced and the size distribution becomes very narrow. The crystal lattice constants have the trend to decrease, and celi volumes appear as shrinkable.

关键词： Additive AlCl_3 Nanocrystalline TiO_2 crystal phase Particle size Microstructural parameters

crystal phase-Based Epitaxial Growth of Noble Metal Nanostructures

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Crystal Phase-Based Epitaxial Growth of Noble Metal Nanostru...

crystal phases and Chemical Stabilities of YSi₂ Powders Fabricated from Low and High Purity Si and Y Powders

中国化学会第十届全国无机化学学术会议

作者： Qipeng Lu School of Materials Science and Engineering University of Science and Technology Beijing

crystal phase engineering offers opportunities for the rational design and synthesis of noble metal nanomaterials with unusual crystal phases which normally do not exist in bulk materials. However, it remains a challenge to use these materials as seeds to construct heterometallic nanostructures with desired crystal phases and morphologies for promising applications such as catalysis. This presentation will provide a strategy for the synthesis of binary and ternary hybrid noble metal nanostructures. The synthesized crystal-phase heterostructured 4 H/fcc Au nanowires(NWs) enable the epitaxial growth of Ru nanorods(NRs) on the 4 H phase and fcc-twin boundary in Au NWs, resulting in hybrid Au-Ru NWs. Moreover, the method can be extended to the epitaxial growth of Rh, Ru-Rh, and Ru-Pt NRs on the 4 H/fcc Au NWs to form unique hybrid NWs. Based on the obtained hybrid nanostructures, hierarchical 4 H/fcc Ru nanotubes(NTs) could be synthesized by a hard template-mediated method, in which 4 H/fcc Au nanowires(NWs) served as sacrificial templates which were then etched by copper ions(Cu) in dimethylformamide. The obtained hierarchical 4 H/fcc Ru NTs contain ultrathin Ru shells(5-9 atomic layers) and tiny Ru nanorods(NRs) with length of 4.2 ± 1.1 nm and diameter of 2.2 ± 0.5 nm vertically decorated on the surface of Ru shells. As an electrocatalyst for the hydrogen evolution reaction(HER) in alkaline media, the hierarchical 4 H/fcc Ru NTs exhibit excellent electrocatalytic performance, which is better than 4 H/fcc Au-Ru NWs, commercial Pt/C, Ru/C and most of the reported electrocatalysts.

关键词： crystal phase Epitaxial growth Noble metal Nanostructure

来源： cnki会议评论

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Journal of Materials Science and Chemical Engineering 2022年第2期10卷 18-28页

作者： Ren Matsushima Mikito Kitayama Department of Life Environment and Applied Chemistry Fukuoka Institute of Technology Fukuoka Japan

Y-Si compounds with the composition of Y:Si = 1:2 were fabricated using Yttrium and Silicon raw powders with low and high purity in various atmospheres and temperatures. Although the latest Y-Si phase diagram shows that the α- and β-YSi2 phases are the stable phases for the stoichiometric composition of Y:Si = 1:2, the current experimental results suggest that the high temperature phase with the hexagonal structure, β-Y3Si5, would be the stable phase for this composition, and that the high temperature phase with the orthorhombic structure, β-YSi2, would be the meta-stable phase with high oxygen impurity content. It was demonstrated that YSi2 powders possess much superior chemical stability than Yttrium metal. It was found that the best dispersing solvent was 2-propanol for YSi2 powder.

关键词： YSi2 Yttrium Silicide crystal phase Chemical Stability Oxygen Impurity

phase Composition of Sputtered Film from a Mixture Target of Hydroxyapatite and Strontium-apatite

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Journal of Materials Science & Technology 2013年第1期29卷 1-6页

作者： K.Ozeki T.Hoshino H.Aoki T.Masuzawa Department of Mechanical Engineering Ibaraki University International Apatite Co. Ltd.

To obtain an Sr-substituted hydroxyapatite thin film, sputter-coating was performed on a cellulose filter acting as a substrate from the mixture target of hydroxyapatite （HA） and strontium-apatite （SrAp） at an Ar pressure of 0.5-5.0 Pa. The ratio of the SrAp in the mixture target was varied from 25% to 100%. After coating, the films were heated at 700 ℃ to remove the cellulose filter substrate, and the crystalline phases were identified by X-ray diffraction （XRD）. The sputter-coated film was identified as the Sr-substituted /3-tri-calcium phosphate （TCP） and the Sr-substituted/3-calcium pyrophosphate （CPP） as well as the Sr-substituted HA. The weight ratio of the Sr-substituted HA decreased with increasing Ar pressure or with an increasing ratio of SrAp to HA in the target. The average Sr/（Ca ＋ Sr） molar ratio in the film was 1.9%-3.5% slightly lower than the initial SrAp ratio of the target, and the ratio was not influenced by the Ar pressure. In the （Sr ＋ Ca）/P ratio, the ratio decreased while increasing the SrAp ratio in the target.

关键词： Sputtering Hydroxyapatite Strontium Strontium-apatite crystal phase

Recent progress in structural modulation of metal nanomaterials for electrocatalytic CO_(2) reduction

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Rare Metals 2021年第6期40卷 1412-1430页

作者： Chen-Huai Yang Farhat Nosheen Zhi-Cheng Zhang Tianjin Key Laboratory of Molecular Optoelectronic Sciences Department of ChemistrySchool of ScienceTianjin University&Collaborative Innovation Center of Chemical Science and EngineeringTianjin 300072China Department of Chemistry Division of Science and TechnologyUniversity of EducationLahore 54660Pakistan

The electrochemical CO_(2) reduction(ECR)into value-added products presents an appealing approach to mitigate CO_(2) emission caused by excess consumption of fossil fuels.To obtain high catalytic activity and selectivity toward target product in ECR,designing and developing a stable and efficient electrocatalyst is of significant importance.To date,metal nanomaterials have been widely applied as electrocatalysts for ECR due to their unique physicochemical properties.The structural modulation of metal nanomaterials is an attractive strategy to improve the catalytic performance.In this review,the recent progress of structural modulation,including size,facet,grain boundary,composition,interface,ligand modification,and crystal phase,is systematically summarized from both theoretical and experimental aspects.Finally,the opportunities and perspectives of structural modulation of metal nanomaterials for ECR are proposed.

关键词： CO_(2)reduction Structural modulation Electrocatalysis Metal nanomaterial crystal phase

Competition between acidic sites and hydrogenation sites in Cu/ZrO_(2) catalysts with different crystal phases for conversion of biomass-derived organics

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Green Energy & Environment 2021年第4期6卷 557-566页

作者： Yuewen Shao Tingting Wang Kai Sun Zhanming Zhang Lijun Zhang Qingyin Li Shu Zhang Guangzhi Hu Xun Hu School of Material Science and Engineering University of JinanJinan250022China College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental ScienceYunnan UniversityKunming 650504China

Oxides with different crystal phases can have important effects on the configuration of surface atoms,which can further affect the distribution of hydrogenation sites and acidic sites as well as the competitions of these varied types of catalytic sites.This could be potentially used to tailor the distribution of the products.In this study,zirconium oxides with different crystal phases supported copper catalysts were prepared for the hydrogenation of the biomass-derived furfural,vanillin,etc.The results showed that both calcination temperature and Cu species affected the shift of zirconia from tetragonal phase to the monoclinic phase.Monoclinic zirconia supported copper catalyst can effectively catalyze the hydrogenation of furfural to furfuryl alcohol via hydrogenation route due to its low amount of Brønsted acidic sites,although the surface area and the exposed metallic Cu surface area were much lower than the tetragonal zirconia supported copper catalyst.Zirconia with tetragonal or tetragonal/monoclinic phases supported copper catalysts contain abundant acidic sites and especially the Br?nsted acidic sites,which catalyzed mainly the conversion of furfural via the acid-catalyzed routes such as the acetalization,rather than the hydrogenation.The acidic sites over the Cu/ZrO_(2)catalyst played more predominant roles than the hydrogenation sites in determining the conversion of the organics like furfural and vanillin.

关键词： Zirconia supported copper catalyst crystal phase Hydrogenation Hydrogenation sites Acidic sites

phase engineering of metal-organic frameworks

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Aggregate 2022年第1期3卷 93-107页

作者： Chen Ma Long Zheng Gang Wang Jun Guo Liuxiao Li Qiyuan He Ye Chen Hua Zhang Department of Chemistry The Chinese University of Hong KongShatinHong KongChina Department of Chemistry City University of Hong KongKowloonHong KongChina Department of Materials Science and Engineering City University of Hong KongKowloonHong KongChina Hong Kong Branch of National Precious Metals Material Engineering Research Center(NPMM)City University of Hong KongKowloonHong KongChina Shenzhen Research Institute City University of Hong KongShenzhenChina

As an important category of porous crystalline materials,metal-organic frameworks(MOFs)have attracted extensive research interests owing to their unique structural features such as tunable pore structure and enormous surface area.Besides controlling the size,dimensionality,and composition of MOFs,further exploring the crystal-phase-dependent physicochemical properties is essential to improve their performances in various applications.Recently,great progress has been achieved in the phase engineering of nanomaterials(PEN),which provides an effective strategy to tune the functional properties of nanomaterials by modulating the arrangement of atoms.In this review,we adopt“phase”instead of“topology”to describe the crystal structure of MOFs and summarize the recent advances in phase engineering of MOFs.The two main strategies used to control the phase of MOFs,that is,phasecontrolled synthesis and phase transformation of MOFs,will be highlighted.The roles of various reaction parameters in controlling the crystal phase of MOFs are discussed.Then,the phase dependence of MOFs in various applications including luminescence,adsorption,and catalysis are introduced.Finally,some personal perspectives about the challenges and opportunities in this emerging field are presented.

关键词： crystal phase metal-organic frameworks phase engineering phase transformation phase-controlled synthesis

Effect of Plasma Spheroidization Process on the Microstructure and crystallographic phases of Silica, Alumina and Nickel Particles

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Plasma Science and Technology 2007年第5期9卷 611-615页

作者：胡鹏闫世凯袁方利白柳杨李晋林陈运法 Institute of Process Engineering Chinese Academy of SciencesBeijing 100080China Graduate University of Chinese Academy of Sciences Beijing 100049China Institute of Process Engineering Chinese Academy of SciencesBeijing 100080China

During the plasma spheroidization process powders undergo different changes in their microstructures and crystal phases. In this paper, simple calculation of heat transfer between the plasma and a suspended particle was performed based on three hypotheses for the purpose of guiding experiments. Experimental investigation of the crystal phases and microstructural changes during the plasma processing was made using silica, alumina and nickel powders as starting materials. It has been revealed from the experimental results that these materials undergo different changes in crystal phases and microstructures, and these changes are essentially determined by the structures, properties and aggregate states of the starting materials.

关键词： radio frequency plasma spheroidization microstructure crystal phase silica,alumina nickel