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ROLES OF ALUMINA IN ZIRCONIA-BASED SOLID-ELECTROLYTE

JOURNAL OF materials SCIENCE 1995年第4期30卷 923-931页

作者： GUO, X YUAN, RZ State Key Laboratory for Synthesis and Processing of Advanced Materials Wuhan University of Technology Hubei Province People's Republic of China

Up to 5 mol% Al2O3 was added to 9 mol% Y2O3-stabilized ZrO2, and the roles of Al2O3 were systematically studied by means of the complex impedance approach, the positron annihilation technique, SEM, TEM, and electron probe microanalysis from the following aspects: (1) the existence of forms of Al2O3 in ZrO2, (2) the effects of Al2O3 on the microstructure of ZrO2, (3) the effects of Al2O3 on the resistance of ZrO2, (4) the microstructure and property changes of ZrO2 with Al2O3 addition during ageing at 940 degrees C. Two types of grain boundary phase, crystal and amorphous, were discovered. The Al2O3 segregation at grain boundaries can promote the mobility of the grain boundaries and thus results in a low density, because of entrapped pores. The Al2O3 addition decreases the grain-boundary resistance in two ways: to scavenge the SiO2 and CaO located at grain boundaries, and to form crystal grain-boundary phases with very high crystal defect concentrations. Ordered microdomains of Zr3Y4O12 were precipitated from ZrO2 grains during ageing, and aluminium was found to facilitate the precipitation.

关键词： Zirconia

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Nanostructured bimetallic Zn/Co in N-doped carbon as an efficient catalyst for the alcohol dehydrogenation to carboxylic acids under solvent-free conditions

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Journal of materials Science & technology 2023年第30期161卷 111-122页

作者： Zhong-Hui Zheng Somboon Chaemchuen Jun-Fei Gu Jing Hang Wei Sang Ji-Chao Wang Ye Yuan Cheng Chen State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The catalytic alcohol dehydrogenation to carboxylic acids has been demonstrated as an atom-economic and environmental-friendly synthetic ***,the reported catalysts either require relatively complicated synthesis or exhibit high activity only in the presence of a ***,it is still in high demand to obtain catalysts that feature facile synthesis and perform well even without any ***,a series of nanostructured bimetallic Zn/Co species embedded in N-doped hierarchical porous carbon were fabricated in a facile and green *** significantly,the best-performing material(Zn/Co@NC-800)was identified as the first heterogeneous catalyst to enable this transformation under solvent-free ***,the as-prepared composites were comprehensively investigated to de-termine their structural and morphological properties,which rationalized the superiority of Zn/Co@NC-800 over the other synthesized *** studies signified that Co sites(both Co^(0)and Co^(2+))and N species(mainly pyridinic N)were probably involved in this process,functioning as the Lewis acid site and basic site,***,this study could provide a simple and sustainable method for carboxylic acid synthesis.

关键词： Heterogeneous catalysis Bimetallic ZIFs Pyrolysis Solvent-free Alcohol dehydrogenation Carboxylic acids

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Origin of shear induced‘catching bonds’on half Heusler thermoelectric compounds XFeSb(X=Nb,Ta)and SnNiY(Y=Ti,Zr,Hf)

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npj Computational materials 2024年第1期10卷 2607-2614页

作者： Haoqin Ma Xiege Huang Zhongtao Lu Xiaobin Feng Bo Duan Wenjuan Li Yinhan Liu Pengcheng Zhai Guodong Li Qingjie Zhang Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics School of ScienceWuhan University of Technology430070 WuhanChina State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology430070 WuhanChina

Half Heusler materials exhibit excellent thermoelectric and mechanical properties,rendering them potential candidates for advanced thermoelectric ***,the developments on interrelated devices are impeded by their inherent brittleness and limited ***,it exists the potential ductility on half Heusler materials with face-centered cubic sub-lattices through the expectation of the occurrence of shear-induced‘catching bonds’which can result in excellent ductility on other face-centered cubic materials.

关键词： ductility cubic rendering

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Approaching high oxygen evolution reaction performance by synergetic dual-ion leaching

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Nano Research 2024年第9期17卷 7975-7983页

作者： Hancheng Ma Yao Ding Jianqi Li Wei Peng Liqiang Mai School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Self-reconstruction of catalysts during oxygen evolution reaction(OER)is crucial for the development of energy conversion ***,the relationship between the specific atomic structure of pre-catalysts and their electrocatalytic behavior after reconstruction via dual-ion leaching has not been extensively *** this work,we design a highly effective non-noble metal OER catalyst with heterointerface through continuous self-reconstruction of Co_(2)(OH)_(3)Cl@NiMoO_(4)as pre-catalyst by a straightforward dual-ion(***_(4)^(2-)and Cl^(-))***-situ Raman and in-situ Fourier transform infrared(FT-IR)spectroscopy have precisely identified the progressive phase transformation of the pre-catalyst during self-reconstruction,which results in a stable heterojunction of CoOOH and NiOOH(CoOOH@NiOOH).Further calculations based on density functional theory(DFT)of CoOOH@NiOOH evident that more electrons will be aggregated in the Fermi level of ***,Gibbs free energy(ΔG)for different OER steps of CoOOH@NiOOH exhibit lower energy costs of all intermediates,implying the well catalytic ***,the catalyst derived from dual-ion leaching displays outstanding OER performance,characterized by an overpotential of 275 mV at a current density of 10 mA·cm^(-2)and exceptional stability over 12 h *** work successfully paves a way of finding high-performance OER catalysts based on non-noble metal through dual-ion leaching during self-reconstruction.

关键词： dual-ion leaching oxygen evolution reaction chemical reconstruction NiMoO_(4) Co_(2)(OH)_(3)Cl

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Effect of Composite Composition on the Contact Angle of B_(4)C-xTiB_(2)/Cu

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Journal of Wuhan University of technology(materials Science) 2024年第5期39卷 1116-1120页

作者： HU Dong ZHANG Xin ZHANG Jinyong LEI Liwen State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Key Laboratory of Theory and Application of Advanced Materials Mechanics Wuhan University of TechnologyWuhan 430070China

The wetting behavior of molten Cu on the B_(4)C-xTiB_(2)ceramic composites was investigated in this *** results show that the contact angle of molten Cu alloy on B_(4)C-TiB_(2)ceramic composites is linear with the composition rate of TiB_(2)or B_(4)C while the temperature is in the range of 1300 to 1350℃,consistent with the expectation of the commonly used theoretical ***,a nonlinear relationship between the contact angle and the composition rate unexpectedly occurred at temperatures ranging from 1400 to 1500℃.The big difference of the contact angles between the molten metal and the components in the composites was found to be the key *** result identifies that the commonly used theoretical method only works at a limited difference of the contact angle of the liquid on the different phases in the composites,and fails at a big difference.

关键词： wetting B_(4)C-TiB_(2) composites interfacial reaction

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Effect of Fluoride on the Ion-association of Calcium Phosphate and Crystallization of Hydroxyapatite

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Journal of Wuhan University of technology(materials Science) 2024年第4期39卷 831-838页

作者：宋昊月 CAI Meng 袁萍邹朝勇 School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Using a titration setup to accurately control the reaction conditions and in situ monitor the reaction,we showed that fluoride exhibited negligible effects on the ion association process of calcium and phosphate and the formation of ACP nanospheres in a buffer solution with constant ionic ***,the stability of ACP increased with increasing fluoride concentration,which was ascribed to the inhibitory effect of fluoride on the aggregation of ACP nanospheres and the nucleation of nanocrystals on the surface of ACP ***,fluoride could inhibit the lateral growth of HAP nanosheets and promote the formation of rod-like *** results further improve our understanding of the crystallization pathway of HAP crystals and the regulatory effects of fluoride.

关键词： crystallization amorphous calcium phosphate hydroxyapatite fluoride

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Preparation and Mechanical Properties of Zirconia Ceramics Doped with Different Y_(2)O_(3)Contents

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Journal of Wuhan University of technology(materials Science) 2023年第6期38卷 1287-1292页

作者： SONG Yanwei ZHAO Xiaoqing WANG Aiyang XIONG Yan DONG Yanling WANG Weimin State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Materials and Chemical Engineering Hubei University of TechnologyWuhan 430068China

The sintering behavior and mechanical properties of zirconia doped with 2.0mol%-3.0mol%Y_(2)O_(3)were studied by pressure-less *** experimental results show that the densification temperature of zirconia ceramics increases gradually with the decrease of Y_(2)O_(3)doping content by which decreases the sintering driving force due to the lower oxygen vacancy concentration of the ***,the bending strength and fracture toughness of the prepared zirconia ceramics increase with the decrease of Y_(2)O_(3)doping *** can be attributed to the fact that the phase stability of tetragonal zirconia decreases with the decrease of Y_(2)O_(3)doping content,which is easier to induce"phase transformation toughening"and dissipate impact *** relative density,bending strength and fracture toughness of 2.0 mol%Y_(2)O_(3)doped zirconia ceramics(2.0Y-ZrO_(2))sintered at 1525℃are 99.00%,1256.65±20.82 MPa and 9.85±0.13 MPa·m^(1/2),respectively.

关键词： yttria-stabilized tetragonal zirconia polycrystal(Y-TZP)ceramics sintering behaviors mechanical properties

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Atomic Level Dispersed Metal–Nitrogen–Carbon Catalyst toward Oxygen Reduction Reaction: synthesis Strategies and Chemical Environmental Regulation

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Energy & Environmental materials 2021年第1期4卷 5-18页

作者： Hengbo Yin Huicong Xia Shuyan Zhao Kexie Li Jianan Zhang Shichun Mu College of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

For development and application of proton exchange membrane fuel cell(PEMFC) energy transformation technology, the cost performance must be elevated for the catalyst. At present, compared with noble metal-based catalysts, such as Pt-based catalysts, atomically dispersed metal–nitrogen–carbon(M–N–C) catalysts are popularity and show great potential in maximizing active site density, high atom utilization and high activity,making them the first choice to replace Pt-based catalysts. In the preparation of atomically dispersed metal–nitrogen–carbon catalyst, it is difficult to ensure that all active sites are uniformly dispersed, and the structure system of the active sites is not optimal. Based on this, we focus on various approaches for preparing M–N–C catalysts that are conducive to atomic dispersion, and the influence of the chemical environmental regulation of atoms on the catalytic sites in different catalysts. Therefore, we discuss the chemical environmental regulation of the catalytic sites by bimetals, atom clusters, and heteroatoms(B, S, and P). The active sites of M–N–C catalysts are explored in depth from the synthesis and characterization, reaction mechanisms, and density functional theory(DFT)calculations. Finally, the existing problems and development prospects of the current atomic dispersion M–N–C catalyst are proposed in detail.

关键词： atomic-level catalyst chemical environmental effects metal-nitrogen-carbon oxygen reduction reaction synthesis strategy

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Reduced water dissociation barrier on constructing Pt-Co/CoO_(x)interface for alkaline hydrogen evolution

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Nano Research 2022年第6期15卷 4958-4964页

作者： Yandong Wang Wei Wu Runzhe Chen Caoxin Lin Shichun Mu Niancai Cheng College of Materials Science and Engineering Fuzhou UniversityFuzhou 350108China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Water dissociation process is generally regarded as the rate-limiting step for alkaline hydrogen evolution reaction(HER),and severely inhibits the catalytic efficiency of Pt based *** overcome this problem,the in-situ constructed interfaces of PtCo alloy and amorphous cobalt oxide(CoO_(x))on the carbon powder are *** amorphous CoO_(x)at Pt-Co/CoO_(x)interfaces not only provide active sites for water dissociation to facilitate Volmer step,but also produce the strong electronic transfer with ***,the obtained interfacial catalysts exhibit outstanding alkaline HER performance with a Tafel slope of 29.3 mV·dec^(−1)and an ultralow overpotential of only 28 mV at 10 mA·cm^(−2).Density functional theory(DFT)reveals that the electronic accumulation on the interfacial Co atom in Pt-Co/CoO_(x)constructing the novel active site for water *** to the Pt-Co,all of the energy barriers for water adsorption,water dissociation and hydrogen adsorption/desorption are reduced in Pt-Co/CoO_(x)interfaces,suggesting a boosted HER kinetics for alkaline HER.

关键词： interfacial construction amorphous cobalt oxide water dissociation dual active site electronic regulation

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Step-scheme CdS/TiO_(2) nanocomposite hollow microsphere with enhanced photocatalytic CO_(2) reduction activity

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Journal of materials Science & technology 2020年第21期56卷 143-150页

作者： Zhongliao Wang Yifan Chen Liuyang Zhang Bei Cheng Jiaguo Yu Jiajie Fan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan430070China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China

Converting solar energy into chemical energy by artificial photosynthesis is promising in addressing the issues of the greenhouse effect and fossil fuel ***,a novel photocatalyst,***/TiO_(2) hollow microspheres(HS),were dedicatedly designed to boost overall photocatalytic ***_(2) nanoparticles were in-situ decorated on the inside and outside the shell of Cd S HS,ensuring close contact between TiO_(2) and *** CdS/TiO2 HS with abundant mesopores inside of the shell boost the light absorption via multiscattering effect as well as accessible to reactions in all *** heterojunction was scrutinized and the charge transfer across it was revealed by in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS).Ultimately,the charge transfer in this composite was determined to follow stepscheme mechanism,which not only facilitates the separation of charge carriers but also preserves strong redox *** from the intimate linkage between Cd S and TiO_(2) and the favorable step-scheme heterojunction,enhanced photocatalytic CO_(2) reduction activity was *** CH4 yield rate of CdS/TiO_(2) reaches 27.85μmol g^(–1) h^(–1),which is 145.6 and 3.8 times higher than those of pristine CdS and TiO_(2),*** work presents a novel insight into constructing step-scheme photocatalytic system with desirable performance.

关键词： Step-scheme heterojunction CdS TiO_(2) Hollow microspheres Photocatalytic CO2 reduction

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