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in-situ synthesis of TiO_2 nanostructures on Ti foil for enhanced and stable photocatalytic performance

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Journal of Materials Science & Technology 2019年第4期35卷 615-622页

作者： Ke Wang Baodan Liu Jing Li Xiaoyuan Liu Yang Zhou Xinglai Zhang Xiaoguo Bi Xin Jiang School of Materials Science and Engineering University of Science and Technology of China Shenyang National Laboratory for Materials Science (SYNL) Institute of Metal Research (IMR)Chinese Academy of Sciences (CAS) School of Renewable Energy Shenyang Institute of Engineering

TiO_2 nanostructures with strong interfacial adhesion and diverse morphologies have been in-situ grown on Ti foil substrate through a multiple-step method based on conventional plasma electrolytic oxidation(PEO) technology, hydrothermal reaction and ion exchange process. The PEO process is critical to the formation of TiO_2 seeding layer for the nucleation of Na_2Ti_3O_7 and H_2Ti_3O_7 mediates that are strongly attached to the Ti foil. An ion exchange reaction can finally lead to the formation of H_2Ti_3O_7 nanostructures with diverse morphologies and the calcination process can turn the H_2Ti_3O_7 nanostructures into TiO_2 nanostructures with enhanced crystallinity. The morphology of the TiO_2 nanostructures including nanoparticles(NP), nanowhiskers(NWK), nanowires(NW) and nanosheets(NS) can be easily tailored by controlling the NaOH concentration and reaction time during hydrothermal process. The morphology, composition and optical properties of TiO_2 photocatalysts were analyzed using scanning electron microscope(SEM), X-ray diffraction(XRD), photoluminescence(PL) spectroscopy and UV–vis absorption spectrum. Photocatalytic tests indicate that the TiO_2 nanosheets calcined at 500?C show good crystallization and the best capability of decomposing organic pollutants. The decoration of Ag cocatalyst can further improve the photocatalytic performance of the TiO_2 nanosheets as a result of the enhanced charger separation efficiency. Cyclic photocatalytic test using TiO_2 nanostructures grown on Ti foil substrate demonstrates the superior stability in the photodegradation of organic pollutant, suggesting the promising potential of in-situ growth technology for industrial application.

关键词： Plasma electrolytic oxidation in-situ growth TiO2 Photocatalysis Ag co-catalyst

in-situ quantification of the surface roughness for facile fabrications of atomically smooth thin films

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Nano Research 2022年第2期15卷 1654-1659页

作者： Genhao Liang Long Cheng Junkun Zha Hui Cao Jingxian Zhang Qixin Liu Mingrui Bao Jia Liu Xiaofang Zhai Hefei National Laboratory for Physical Science at Microscale Department of PhysicsUniversity of Science and Technology of ChinaHefei 230026China School of Physical Science and Technology ShanghaiTech UniversityPudongShanghai 201210China X-ray Science Division Advanced Photon SourceArgonne National LaboratoryLemontIL 60439USA

This work presents an in-situ technique to quantify the layer-by-layer roughness of thin films and heterostructures by measuring the spectral profile of the reflection high-energy electron diffraction(RHEED).The characteristic features of the diffraction spot,including the vertical to lateral size ratio c/b and the asymmetrical ratio c_(1)/c_(2) along the vertical direction,are found to be quantitatively dependent on the surface *** quantitative relationships between them are established and discussed for different incident angles of high-energy *** an example,the surface roughnesses of LaCoO_(3) films grown at different temperatures are obtained using such an in-situ technique,which are confirmed by the ex-situ atomic force ***,the in-situ measured layer-by-layer roughness oscillations of two LaCoO_(3) films are demonstrated,revealing drastically different information from the intensity *** experiments assisted with the in-situ technique demonstrate an outstanding high resolution down to-0.1 ***,the new quantitative RHEED technique with real-time feedbacks significantly escalates the thin film synthesis efficiency,especially for achieving atomically smooth surfaces and *** opens up new prospects for future generations of thin film growth,such as the artificial intelligence-assisted thin film growth.

关键词： reflection high-energy electron diffraction roughness thin film growth high efficiency in-situ real time

in-situ fabrication of Mo6S6-nanowire-terminated edges in monolayer molybdenum disulfide

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Nano Research 2018年第11期11卷 5849-5857页

作者： Wei Huang Xiaowei Wang Xujing Ji Ze Zhang Chuanhong Jin State Key Laboratory of Silicon Materials School of Materials Science and Engineering Zhejiang University Hangzhou 310027 China

Edge structures are highly relevant to the electronic, magnetic, and catalytic properties of two-dimensional (2D) transition metal dichalcogenides (TMDs) and their one-dimensional (1D) counterparts, i.e., nanoribbons, and should be precisely tailored for the desired application. In this work, we report the formation of novel Mo6S6 nanowire (NW)-terminated edges in monolayer molybdenum disulfide (MoS2) via an e–beam irradiation process combined with high temperature heating. The atomic structures of the NW-terminated edges and the dynamic formation process were observed experimentally using scanning transmission electron microscopy. Further analysis showed that the NW-terminated edge could be formed on both the Mo-zigzag (ZZ) edge and S-ZZ edge and could exhibit a stability superior to that of the pristine ZZ and armchair (AC) edges. In addition, analogous edge structures could also be formed in MoS2 nanoribbons and other TMD materials such as MoxW1−xSe2. We believe that these novel edge structures may impart novel properties to the 2D and 1D TMD materials and provide new opportunities for their applications in catalytic, spintronic, and electronic devices.

关键词： molybdenum disulfide (MoS_2) transition metal dichalcogenides nanowire edge structure in-situ

in-situ observation of solid-liquid interface transition during directional solidification of Al-Zn alloy via X-ray imaging

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Journal of Materials Science & Technology 2020年第4期39卷 113-123页

作者： Yuanhao Dong Sansan Shuai Tianxiang Zheng Jiawei Cao Chaoyue Chen Jiang Wang Zhongming Ren State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai UniversityShanghai 200444China

The morphological instability of solid/liquid(S/L)interface during solidification will result in different patterns of *** this study,two dimension(2 D)and three dimension(3 D)in-situ observation of solid/liquid interfacial morphology transition in Al-Zn alloy during directional solidification were performed via X-ray *** a condition of increasing temperature gradient(G),the interface transition from dendritic pattern to cellular pattern,and then to planar growth with perturbation was *** effect of solidification parameter(the ratio of temperature gradient and growth velocity(v),G/v)on morphological instabilities was investigated and the experimental results were compared to classical"constitutional supercooling"*** results indicate that 2 D and 3 D evolution process of S/L interface morphology under the same thermal condition are *** seems that the S/L interface in 2 D observation is easier to achieve planar growth than that in 3 D,implying higher S/L interface stability in 2 D thin plate *** can be explained as the restricted liquid flow under 2 D solidification which is beneficial to S/L interface *** in-situ observation in present study can provide coherent dataset for microstructural formation investigation and related model validation during solidification.

关键词： Al-Zn alloy Directional solidification Solid/liquid interface instability in-situ observation X-ray imaging

in-situ Nitrogen Doping of the TiO2 Photocatalyst Deposited by PEALD for Visible Light Activity

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Plasma Science and Technology 2014年第3期16卷 239-243页

作者：饶志鹏万军李超波陈波刘键黄成强夏洋 Key Laboratory of Microelectronics Devices & Integrated Technology Institute of MicroelectronicsChinese Academy of Sciences Jiaxing Research and Commercialization Center for Microelectronics Equipment Jiaxing Kemin Electronic Equipment & Technologies CO. LTD

In this paper, an N-doped titanium oxide （TiO2） photocatalyst is deposited by a plasma-enhanced atomic layer deposition （PEALD） system through the in-situ doping method. X-ray photoelectron spectroscopy （XPS） analysis indicates that substitutional nitrogen atoms （-395.9 eV） with 1 atom% are effectively doped into TiO2 films. UV-VIS spectrometry shows that the in-situ nitrogen doping method indeed enhances the visible-activity of TiO2 films in the 425-550 nm range, and the results of the performance tests of the N-doped TiO2 films also imply that the photocatalysis activity is improved by in-situ doping. The in-situ doping mechanism of the N-doped TiO2 film is suggested according to the XPS results and the typical atomic layer deposition process.

关键词： plasma-enhanced atomic layer deposition in-situ nitrogen plasma N-dopedTiO2 photocatalyst

in-situ SiN combined with etch-stop barrier structure for high-frequency AlGaN/GaN HEMT

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Chinese Physics B 2020年第4期29卷 430-433页

作者： Min-Han Mi Sheng Wu Ling Yang Yun-Long He Bin Hou Meng Zhang Li-Xin Guo Xiao-Hua Ma Yue Hao Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices School of MicroelectronicsXidian UniversityXi'an 710071China School of Advanced Materials and Nanotechnology Xidian UniversityXi'an 710071China School of Physics and Optoelectronic Engineering Xidian UniversityXi'an 710071China

The etch-stop structure including the in-situ SiN and AlGaN/GaN barrier is proposed for high frequency *** etch-stop process is realized by placing an in-situ SiN layer on the top of the thin AlGaN barrier.F-based etching can be self-terminated after removing SiN,leaving the AlGaN barrier in the gate *** this in-situ SiN and thin barrier etch-stop structure,the short channel effect can be suppressed,meanwhile achieving highly precisely controlled and low damage etching *** device shows a maximum drain current of 1022 mA/mm,a peak transconductance of 459 mS/mm,and a maximum oscillation frequency(fmax)of 248 GHz.

关键词： AlGaN/GaN in-situ SiN etch-stop barrier

in-situ straining observation on crack initiation and growth in an intermetallic Al_(67)Mn_8Ti_(25)alloy

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中国有色金属学会会刊：英文版 1999年第4期9卷 810-813页

作者：文九巴戎咏华陈世朴胡赓祥上海交通大学材料科学与工程学院上海

in-situ straining SEM observations of an intermetallic Al67Mn8Ti25 alloy were carried out on sheet specimens containing notch with root radius about 100μm. The results show that the crack initiation occurs at notch root along grain boundary, and it grows very rapidly in transgranular manner. During the crack growing, some crack branches and segments are formed. Occasionally when the crack propagates in the direction close to grain boundary, it grows intergranularly along a part of boundary. The observed crack propagation process indicates that the alloy is very brittle at ambient temperatures.

关键词： Al3Ti alloys in-situ observation crack propagation

in-situ A1/24Si Functional Graded Materials Prepared by Electromagnetic Separation

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Journal of Materials Science & Technology 2002年第5期18卷 385-386页

作者： KeLI JunWANG DaSHU BaodeSUN YaoheZHOU Coll. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

Cylinder-like in-situ AI/24Si FGMs were produced by using electromagnetic separating process. Si primary phase reinforced layer with volume fraction as high as 16 pct was formed at the outer region of the cylinder-like samples where the local hardness and wear resistance were enhanced remarkably. Moreover, both of strength and ductility in the inner region provided insurance of reliable strength for this as-cast gradient material. It indicated that general mechanical properties such as good wear resistance at the outer region and good ductility in the central part could be obtained with the optimized redistribution of the Si primary particles under the electromagnetic force.

关键词： FGMs in-situ Electromagnetic separation

in-situ synthesis of nanoparticles via supersolubilizing micelle self-assembly

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Science China Chemistry 2007年第1期50卷 105-113页

作者： WANG DingCong Fushun Research Institute of Petroleum&Petrochemicals,China Petroleum&Chemical Corporation(SINOPEC),Fushun 113001, China(email:wangdingcong@***) Fushun Research Institute of Petroleum & Petrochemicals China Petroleum & Chemical Corporation (SINOPEC) Fushun China

in-situ synthesis of nano-particles using the self-assembly of molten salt and super soluble micellae was proposed based on a phenomenon of super solubilization of molten salt in reverse micellae and its self-assembly when the concentration reached up to 95%(w/w).The mechanism of the self-assembly indicates that the self-assembly of molten salt occurs in a reverse micelle where a homogenous phase is established between 5%(w/w)of a surfactant with a VB value of less than 1 and a hydrocarbon spe- *** synthesis has some unique features,such as being free of water,highly effective deposition and narrow distribution of particle size.

关键词： molten salt self-assembly supersolubilization in-situ synthesis nanoparticle