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Cobalt hollow nanospheres： controlled synthesis, modification and highly catalytic performance for hydrolysis of ammonia borane

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Science Bulletin 2017年第5期62卷 326-331页

作者： wangya Wei zumin wang Jie xu Lingbo Zong Kun Zhao Hao wang Haiyan Li Ranbo Yu Department of Physical Chemistry School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Centre for Future Materials University of Southern Queensland Toowoomba Queensland 4350 Australia Beijing Engineering Research Center of Sustainable Urban Sewage System Construction and Risk Control Beijing University of Civil Engineering and Architecture Beijing 100044 China

Size tunable cobalt hollow nanospheres with high catalytic activity for the ammonia borane(AB) hydrolysis have been synthesized by using the solvothermal method. The complexation between Co2+and ethylenediamine is observed to be critical for the formation of the cobalt hollow nanospherical *** morphology of the cobalt hollow nanospheres can be regulated by adjusting the original ethylenediamine/ethanol volume ratio, reaction time and temperature. Impressively, the magnetic property study reveals that the coercivity of the as-synthesized cobalt hollow nanospheres is much enhanced compared with that of bulk cobalt materials. Meanwhile, Co/Pt bimetal hollow nanospheres(Co Pt HS) and graphene-cobalt hollow composite nanospheres(Co HS-r GO) have also been explored. In comparison with the cobalt hollow nanospheres, both the Co Pt HS and Co HS-r GO show higher catalytic activities and better repeatability for the catalytic hydrogen generation from AB hydrolysis. Moreover, it is noted that these catalysts could be recycled by using the magnetic separation method.

关键词： Cobalt hollow nanospheres Controlled synthesis Modification Catalysis Hydrolysis

Microstructure evolution and interface structure of Al-40 wt% Si composites produced by high-energy ball milling

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Journal of Materials Science & Technology 2019年第4期35卷 512-519页

作者： Yuanyuan Chen Zhangping Hu Yifei Xu Jiangyong wang Peter Schützendübe Yuan Huang Yongchang Liu zumin wang School of Materials Science and Engineering Tianjin University Department of Physics Shantou University Max Planck Institute for Intelligent Systems

High silicon content Al-Si composites with a composition of Al-40 wt% Si were fabricated via a highenergy ball milling method. The microstructure evolution of Al-40 wt% Si milled powders and sintered composites has been thoroughly studied by scanning electron microscopy, X-ray diffraction, energydispersive spectrometry and high-resolution transmission electron microscopy. The mechanism of ball milling Al-40 wt% Si powders has been disclosed in detail: fracture mechanism dominating in the early stages, followed by the agglomeration mechanism, finally reaching the balance between the fragments and the agglomerates. It has been found that the average particle sizes of mixed Al-Si powders can be refined to the nanoscale, and the crystallite sizes of Al and Si have been reduced to 10nm and 62nm upon milling for 2h–50h, respectively. The finally formed Al-Si interfaces after ball milling for 50h are wellcohesive. A dense and homogenous Al-40 wt% Si composite have been achieved by solid-state sintering at550?C. The results thus provide an effective support for producing bulk nanostructured Al-Si composites.

关键词： Al-Si composites Interface structure High-energy ball milling Nanocrystalline powders

Facile Synthesis of Fe-based MOFs(Fe-BTC) as Efficient Adsorbent for Water Purifications

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Chemical Research in Chinese Universities 2019年第4期35卷 564-569页

作者： HAN Qian wang zumin CHEN Xiaoyu JIAO Chuangwei LI Haiyan YU Ranbo Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversityf of Science and TechnologyBeijingBeijing 100083P.R.China School of Environment and Energy Engineering Beijing University of Civil Engineering and ArchitectureBeijing 100044P.R.China Key Laboratory of Material Processing and Mold Ministry of EducationZhengzhou UniversityZhengzhou 450001P.R.China

Fe-based metal-organic frameworks(Fe-BTC) were successfully synthesized in a large scale by using a simple one-pot method at room temperature. To understand its composition, texture and morphology, the as-synthesized material was analyzed systematically. Moreover, based on the adsorption property for anionic organic dyes(methyl orange, Congo red), cationic organic dves(methylene blue, rhodamine B) and heavy metal ions(Pb^2+) in aqueous solutions, it was revealed that the obtained Fe-BTC showed excellent capacities and adsorption rates tor different adsorbates. Besides the general adsorption eftect derived from the numerous pores and large specific surface area, the electrostatic forces and Л-Л interactions between benzene rings are believed to play significant roles in the large uptakes of this Fe-BTC sample. And the existence of mesopores in Fe-BTC might accelerate the adsorption.

关键词： One-pot synthesis Metal-organic framework Water purification Adsorption

Anchoring nitrogen-doped Co_(2)P nanoflakes on NiCo_(2)O_(4)nanorod arrays over nickel foam as high-performance 3D electrode for alkaline hydrogen evolution

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Green Energy & Environment 2023年第2期8卷 470-477页

作者： Xiaohao Ji Xiaoyu Chen Lijuan Zhang Cheng Meng Yilei He Xing Zhang zumin wang Ranbo Yu Department of Physical Chemistry School of Metallurgical and Ecological EngineeringUniversity of Science and Technology BeijingBeijing100083China State Key Laboratory of Biochemical Engineering Institute of Process EngineeringChinese Academy of Sciences1 North 2nd StreetZhongguancunHaidian DistrictBeijing100190China

Effective and robust electrocatalysts are mainly based on innovative materials and unique ***,we designed a flakelike cobalt phosphide-based catalyst supporting on NiCo_(2)O_(4)nanorods array,which in-situ grew on the nickel foam(NF)current collector,referring as NCo_(2)P/NiCo_(2)O_(4)/NF *** optimizing the microstructure and electronic structure through 3D hierarchy fabrication and nitrogen doping,the catalyst features with abundant electrochemical surface area,favorable surface wettability,excellent electron transport,as well as tailored d band ***,the as-prepared N-Co_(2)P/NiCo_(2)O_(4)/NF electrode exhibits an impressive HER activity with a low overpotentials of58 mV at 10 mA cm^(-2),a Tafel slop of 75 mV dec^(-1),as well as superior durability in alkaline *** work may provide a new pathway to effectively improve the hydrogen evolution performance of transition metal phosphides and to develop promising electrodes for practical electrocatalysis.

关键词： Hydrogen evolution reaction(HER) Cobalt phosphide Nonprecious electrocatalyst Hierarchal structure Nitrogen doping

Synergistic phosphorized NiFeCo and MXene interaction inspired the formation of high-valence metal sites for efficient oxygen evolution

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Journal of Materials Science & Technology 2022年第11期106卷 90-97页

作者： Ning Li Jingrui Han Kaili Yao Mei Han zumin wang Yongchang Liu Lihua Liu Hongyan Liang School of Materials Science and Engineering Tianjin UniversityTianjin 300350China Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of EducationTianjin UniversityTianjin 300350China College of Innovation and Entrepreneurship Shanghai Jianqiao UniversityShanghai 201306China State Key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science and EngineeringTianjin UniversityTianjin 300354China

Exploring low-cost,high-performance,and stable electrocatalysts toward the oxygen evolution reaction(OER)is highly desired but remains *** metal hydroxide has been wildly utilized as a promising candidate,but practical implementation is impeded by insufficient catalytic activity,easy agglomeration,and poor ***,we report that both phosphorization and combination with MXnene can improve the catalysts’intrinsic activity and ***,MXene also prevents the agglomeration of the nanoparticles,resulting in the enhanced exposure of active *** char-acterizing and density functional theory simulations revealed that P species can attract electrons to pro-mote the formation of high-valence states of adjacent metal atoms,and coupling MXene support can effectively modulate the electronic structure and optimize the d-band center,which boosts the OER ***,the optimized NiFeCoP/Mxene catalyst exhibits a low overpotential of 240 mV at a current density of 10 mA cm^(−2),a small Tafel slope of 55 mV dec^(−1),and superior long-term stability of 40 h in 1 M KOH electrolyte,which is superior to other counterparts.

关键词： Transition metal phosphide Ti3C2Tx MXene Electrocatalyst Oxygen evolution

Numerical Simulation of the Parallel Gap Resistance Welding Process of a Solar Cell and Mo/Pt/Ag Interconnector

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Transactions of Tianjin University 2024年第5期30卷 419-427页

作者： Xingyu Chen Kai wang Zhicheng Wu Bin Su Xinyu Cui Yuan Huang zumin wang Institute of Advanced Metallic Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300350China No.18 Research Institute China Electronics Technology Group CorporationTianjin 300350China

Energy for space vehicles in low Earth orbit(LEO) is mainly generated by solar arrays, and the service time of the vehicles is controlled by the lifetime of these arrays, which depends mainly on the lifetime of the interconnects. To increase the service life of LEO satellites, molybdenum/platinum/silver(Mo/Pt/Ag) laminated metal matrix composite(LMMC) interconnectors are widely used in place of Mo/Ag LMMC and Ag interconnectors in solar arrays. A 2D thermal-electrical-mechanical coupled axisymmetric model was established to simulate the behavior of the parallel gap resistance welding(PGRW) process for solar cells and Mo/Pt/Ag composite interconnectors using the commercial software ANSYS. The direct multicoupled PLANE223 element and the contact pair elements TARGE169 and CONTA172 were employed. A transitional meshing method was applied to solve the meshing problem due to the ultrathin(1 μm) intermediate Pt layer. A comparison of the analysis results with the experimental results revealed that the best parameters were 60 W, 60 ms, and 0.0138 MPa. The voltage and current predicted by the finite element method agreed well with the experimental results. This study contributes to a further understanding of the mechanism of PGRW and provides guidance for finite element simulation of the process of welding with an ultrathin interlayer.

关键词： Solar arrays Parallel gap resistance welding Finite element method Heat transfer coefficient Ultrathin intermediate Pt layer

Microstructure evolution and mechanical properties of linear friction welded S31042 heat-resistant steel

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Journal of Materials Science & Technology 2018年第4期34卷 653-659页

作者： Yanmo Li Yongchang Liu Chenxi Liu Chong Li Zongqing Ma Yuan Huang zumin wang Wenya Li State Key Lab. of Hydraulic Engineering Simulation and Safety School of Materials Science and Engineering Tianjin University School of Materials Science and Engineering Northwestern Polytechnical University

S31042 heat-resistant steel was joined by linear friction welding （LFW） in this study. The microstructure and the mechanical properties of the LFWed joint were investigated by optical microscopy, scanning electronic microscopy, transmission electron microscopy, hardness test and tensile test. A defect-free joint was achieved by using LFW under reasonable welding parameters. The dynamic recrystallization of austenitic grains and the dispersed precipitation of NbCrN particles resulting from the high stress and high temperature in welding, would lead to a improvement of mechanical property of the welded joint. With increasing the distance flom the weld zone to the parent metal, the austenitic grain size gradually increases from -1 μm to - 150 μm, and the microhardness decreases from 301 HV to 225 HV. The tensile strength （about 731 MPa） of the welded joint is comparable to that of the S31042 in the solution-treated state.

关键词： Austenitic steel Welding Microstructure Mechanical property Precipitation

Ultra-fine W-Y_(2)O_(3)composite powders prepared by an improved chemical co-precipitation method and its interface structure after spark plasma sintering

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Tungsten 2019年第3期1卷 220-228页

作者： Weiqiang Hu Qingshuang Ma Zongqing Ma Yuan Huang zumin wang Yongchang Liu Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin 300072China

Y_(2)O_(3)-doped tungsten(W-Y_(2)O_(3))composite powders prepared by a traditional chemical co-precipitation method possess obvious bimodal distribution in size,which would deteriorate their sintering *** bimodal distribution can be effectively eliminated by an improved chemical co-precipitation method,in which the cationic surfactant cetyltrimethyl-ammonium bromide(CTAB)was innovatively *** reduced powders with excellent uniformity have an average grain size of only~31.5 *** is noteworthy that Y_(2)O_(3)particles would fuse and grow with the growth of W grains during subsequent spark plasma sintering(SPS)process,which was rarely reported in relevant literature *** top of that,phase interfaces of sintered W-Y_(2)O_(3)alloys were systematically *** to the intracrystalline oxygen content,the oxygen content at W/Y_(2)O_(3)phase boundaries is relatively *** can be found that the(110)crystal planes of W form coherent,semi-coherent,and non-coherent interfaces with different crystal planes of Y_(2)O_(3).The weak interfacial bonding strength between W and Y_(2)O_(3)phases results from relatively more oxygen impurities as well as more semi-coherent/non-coherent interfaces at phase boundaries compared with the inner W grains.

关键词： Y_(2)O_(3)-doped tungsten Chemical co-precipitation method CTAB SPS Phase boundary

Effect of atomic structure on preferential oxidation of alloys:amorphous versus crystalline Cu-Zr

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Journal of Materials Science & Technology 2020年第5期40卷 128-134页

作者： Yifei Xu Lars P.H.Jeurgens Peter Schützendübe Shengli Zhu Yuan Huang Yongchang Liu zumin wang State Key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science and EngineeringTianjin UniversityTianjin 300350China Swiss Federal Laboratories for Materials Science and Technology Laboratory for Joining Technologies and CorrosionUeberlandstrasse 1298600 DuebendorfSwitzerland Max Planck Institute for Intelligent Systems Heisenbergstrasse 3D-70569 StuttgartGermany

The effect of structural order in the parent alloy substrate on the oxidation kinetics and oxide phase evolution was investigated for the thermal oxidation of amorphous Cu33at.%Zr67at.%and crystalline CuZr2 alloys of identical compositions in the temperature range of 200–250?*** was found that,besides the strong preferential oxidation of Zr in both alloys,the lack of structural order in the amorphous Cu33at.%Zr67at.%alloy results in much slower oxidation kinetics,as well as in distinctly different microstructures of the oxide overgrowth and its Zr-depletion zone in the wake of the ZrO2 overlayer growth *** experimental findings can be rationalized on the basis of the strikingly different atomic mobilities of Cu,Zr and dissolved O in the amorphous and crystalline alloys,which also results in different nucleation barriers for crystalline oxide *** thus obtained knowledge on the underlying oxidation mechanisms provides new and profound insights into the surface engineering of metallic alloys.

关键词： Oxidation Atomic structure Amorphous alloys Cu-Zr HRTEM