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CO oxidation under lean and stoichiometric conditions over ceriazirconia with very low metal contents(Cu,Co,Ag and Pt)

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Journal of Rare Earths 2024年第9期42卷 1669-1681页

作者： J.C.Martínez-Munuera M.P.Yeste A.García-García MCMA group Department of Inorganic Chemistry and Institute of MaterialsUniversity of Alicante Solid Chemistry and Catalysis group Department of Materials ScienceMetallurgic Engineering and Inorganic ChemistryInstitute of Electronic Microscopy and Materials ResearchUniversity of Cádiz

In this work,several ceria-zirconia based catalysts with very lo w（and equimolar） metal contents were prepared,characterised and tested for the CO oxidatio n reaction（under lean and stoichiometric conditions）,trying to emulate those conditions found in a diesel oxidation catalyst（DOC） system from a diesel engine and those encountered under gasoline exhaust（λ=1）.The metals chosen are Cu,Co,Ag and Pt（as a reliable benchmark）.The results reveal enormous differences among reducibility and catalytic activity despite quite similar structural and textural properties of the catalysts,showing differences among dispersion（Ag-catalyst seems to present a low level of dispersion）.This catalyst seems to be characterised,as well,by a strong electronic interaction between Ce and Ag centres which is suggested to yield an improved reducibility under H2-TPR ***,the order in catalytic activity（Cu>Ag>Co≈Pt>>support） seems not to follow the order found in reducibility and the Cu-catalyst seems to be the most active independently on the reaction conditions,yielding nearly overlapped CO oxidation catalytic *** restingly,a stro ng correlation between the catalytic activity under the two conditions tested and the OSC values of the Ce0.8Zr0.2O2-supported metal catalysts is ***,OSC parameter measured at 150℃ can be used as a relevant descriptor to evaluate the CO oxidation activity at low and medium conversions for the investigated catalysts,much better than the H2-TPR measurements.

关键词： CO oxidation Low metal content Ceria-zirconia Copper species OSC parameter Rare earths

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Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

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International Journal of Minerals,Metallurgy and materials 2024年第3期31卷 562-573页

作者： Qianqian Wang Zequn Yao Lijie Guo Xiaodong Shen College of materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions

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Hydration Behavior and Cementitious Properties of Calcium Carbonate-aluminate Minerals Composite

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Journal of Wuhan University of Technology(materials Science) 2024年第1期39卷 126-133页

作者：王冲周帅 ZOU Luyao LIU Jiawen ZHENG Yalin College of materials Science and Engineering Chongqing UniversityChongqing 400045China China West Construction group Co. Ltd.Chengdu 610015China

The purpose of this research is to investigate the hydration behavior and cementitious properties of the mixture of calcium carbonate and aluminate, and to explore whether it can be adopted as a new low-carbon cementitious material. The composite system of calcium carbonate and aluminate minerals is studied by measuring the component of hydration products, the hydration heat, setting time and compressive *** results prove that the composite system has certain cementitious properties and is feasible to prepare new low-carbon cement.

关键词： limestone hydrated calcium carboaluminate cementitious properties mechanical properties

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In-situ construction of grass-like hybrid architecture responsible for extraordinary corrosion performance: Experimental and theoretical approach

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Nano materials Science 2024年第1期6卷 44-59页

作者： T.Suhartono F.Hazmatulhaq Y.Sheng A.Chaouiki M.P.Kamil Y.G.Ko materials Electrochemistry group School of Materials Science and EngineeringYeungnam UniversityGyeongsan38541Republic of Korea Research Center for Advanced materials National Research and Innovation Agency(BRIN)South TangerangBanten15314Indonesia

Despite the engineering potential by the co-existence of inorganic and organic substances to protect vulnerable metallic materials from corrosive environments,both their interaction and in-situ formation mechanism to induce the nature-inspired composite remained less *** present work used three distinctive mercaptobenzazole(MB)compounds working as corrosion inhibitors,such as 2-mercaptobenzoxazole(MBO),2-mercaptobenzothiazole(MBT),and 2-mercaptobenzimidazole(MBI)in a bid to understand how the geometrical structure arising from O,S,and N atoms affected the interaction toward inorganic *** compounds that were used here to control the corrosion kinetics would be interacted readily with the pre-existing MgO layer fabricated by plasma *** phenomenon triggered the nucleation of the root network since MB compounds were seen to be adsorbed actively on the defective surface through the active sites in MB ***,the molecule with twin donor atoms adjacent to the mercapto-sites affected the facile growth of the grass-like structures with‘uniform’distribution via molecular self-assembly,which showed better corrosion performance than those with having dissimilar donor atoms with the inhibition efficiency(η)of 97%*** formation mechanism underlying nucleation and growth behavior of MB molecule was discussed concerning the theoretical calculation of density functional theory.

关键词： Nature-inspired composite Organic-inorganic interaction Corrosion inhibitor Density functional theory Electrochemistry

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Single-atom catalysts for the electrochemical reduction of carbon dioxide into hydrocarbons and oxygenates

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Carbon Energy 2024年第3期6卷 64-117页

作者： Karl Adrian Gandionco Juwon Kim Lieven Bekaert Annick Hubin Jongwoo Lim Department of Chemistry Seoul National UniversitySeoulRepublic of Korea Research group Electrochemical and Surface Engineering(SURF) Department of Materials and ChemistryVrije Universiteit BrusselBrusselsBelgium

The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel *** this technology,an electrocatalytic material and renewable energy-generated electricity drive the conversion of carbon dioxide into high-value chemicals and carbon-neutral *** the past few years,single-atom catalysts have been intensively studied as they could provide near-unity atom utilization and unique catalytic ***-atom catalysts have become one of the state-of-the-art catalyst materials for the electrochemical reduction of carbon dioxide into carbon ***,it remains a challenge for single-atom catalysts to facilitate the efficient conversion of carbon dioxide into products beyond carbon *** this review,we summarize and present important findings and critical insights from studies on the electrochemical carbon dioxide reduction reaction into hydrocarbons and oxygenates using single-atom *** is hoped that this review gives a thorough recapitulation and analysis of the science behind the catalysis of carbon dioxide into more reduced products through singleatom catalysts so that it can be a guide for future research and development on catalysts with industry-ready performance for the electrochemical reduction of carbon dioxide into high-value chemicals and carbon-neutral fuels.

关键词： electrocatalysis electrochemical CO_(2)reduction hydrocarbons oxygenates single-atom catalysts

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Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

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Journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang Pei Cheng Pan Dapeng Zhong Junyi Xiang Xuewei Lv College of materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced materials Chongqing UniversityChongqing 400044China Pangang group Research Institute Co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air *** solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kJ/*** endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kJ/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high *** cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating ***,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(J mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

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Effect of Co on Solidification Characteristics and Microstructural Transformation of Non-equilibrium Solidified Cu-Ni Alloys

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Journal of Wuhan University of Technology(materials Science) 2024年第2期39卷 444-453页

作者：安红恩 Bih-Lii Chua Ismail Saad Willey Yun Hsien Liew materials Engineering Research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia College of Mechanical and Electronic Engineering Huanghe Jiaotong UniversityJiaozuo 454950China Henan Engineering Technology Research Center on Intelligent Manufacturing Technology and Equipment Jiaozuo 454950China Centre of Research in Energy and Advanced materials Faculty of EngineeringUniversiti Malaysia SabahJalan UMS88400 Kota KinabaluSabahMalaysia Nano Engineering and materials Research group Faculty of EngineeringUniversity Malaysia Sabah88400 Kota KinabaluSabahMalaysia

Non-equilibrium solidification structures of Cu55Ni45 and Cu55Ni43Co2 alloys were prepared by the molten glass purification cycle superheating *** variation of the recalescence phenomenon with the degree of undercooling in the rapid solidification process was investigated using an infrared *** addition of the Co element affected the evolution of the recalescence phenomenon in Cu-Ni *** images of the solid-liquid interface migration during the rapid solidification of supercooled melts were captured by using a high-speed *** solidification rate of Cu-Ni alloys,with the addition of Co elements,was ***,the grain refinement structure with low supercooling was characterised using electron backscatter diffraction(EBSD).The effect of Co on the microstructural evolution during nonequilibrium solidification of Cu-Ni alloys under conditions of small supercooling is investigated by comparing the microstructures of Cu55Ni45 and Cu55Ni43Co2 *** experimental results show that the addition of a small amount of Co weakens the recalescence behaviour of the Cu55Ni45 alloy and significantly reduces the thermal strain in the rapid solidification *** the rapid solidification phase,the thermal strain is greatly reduced,and there is a significant increase in the characteristic undercooling ***,the addition of Co and the reduction of Cu not only result in a lower solidification rate of the alloy,but also contribute to the homogenisation of the grain size.

关键词： non-equilibrium solidification recalescence effect solidification character microstructure

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Structural and Luminescent Properties of Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)Green-Emitting Transparent Ceramic Phosphor

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Journal of Wuhan University of Technology(materials Science) 2024年第3期39卷 533-540页

作者：郝留成 MIAO Xiaojun LI Kai ZHONG Jianying 涂兵田 YANG Zhangfu 王皓 Pinggao group Co. LtdPingdingshan 467001China State Key Lab of Advanced Technology for materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 430070China School of materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001China

A series of spinel-type Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)(MgAlON:xMn^(2+))phosphors were synthesized by the solid-state reaction *** transparent ceramic phosphors were fabricated by pressureless sintering followed by hot-isostatic pressing(HIP).The crystal structure,luminescence and mechanical properties of the samples were systematically *** transparent ceramic phosphors with tetrahedrally coordinated Mn^(2+)show strong green emission centered around 515 nm under blue light *** the Mn^(2+)concentration increases,the crystal lattice expands slightly,resulting in a variation of crystal field and a slight red-shift of green emission *** weak absorption peaks in the transmittance spectra originate from the spin-forbidden ^(4)T_(1)(^(4)G)→^(6)A_(1) transition of Mn^(2+).The decay time was found to decrease from 5.66 to 5.16 ms with the Mn^(2+)*** present study contributes to the systematic understanding of crystal structure and properties of MgAlON:xMn^(2+)green-emitting transparent ceramic phosphor which has a potential application in high-power light-emitting diodes.

关键词： transparent ceramic phosphor green emission MgAlON photoluminescence

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Effects of cooling rate on microstructure and microhardness of directionally solidified Galvalume alloy

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China Foundry 2024年第3期21卷 213-220页

作者： Ji-peng Li De-gao Qiao Jian Li Xiao-yang Luo Peng Peng Xian-tao Yan Xu-dong Zhang Gansu Jiu Steel group Hongxing Iron and Steel Co. Ltd.Jiayuguan 735111GansuChina School of materials and Energy Lanzhou UniversityLanzhou 730000China

The influences of cooling rate on the phase constitution,microstructural length scale,and microhardness of directionally solidified Galvalume(Zn-55Al-1.6Si)alloy were investigated by directional solidification experiments at different withdrawal speeds(5,10,20,50,100,200,and 400μm·s^(-1)).The results show that the microstructure of directionally solidified Galvalume alloys is composed of primary Al dendrites,Si-rich phase and(Zn-Al-Si)ternary eutectics at the withdrawal speed ranging from 5 to 400μm·s^(-1).As the withdrawal speed increases,the segregation of Si element intensifies,resulting in an increase in the area fraction of the Si-rich *** addition,the primary Al dendrites show significant refinement with an increase in the withdrawal *** relationship between the primary dendrite arm spacing(λ_(1))and the thermal parameters of solidification is obtained:λ_(1)=127.3V^(-0.31).Moreover,as the withdrawal speed increases from 5 to 400μm·s^(-1),the microhardness of the alloy increases from 90 HV to 151 *** is a combined effect of grain refinement and second-phase strengthening.

关键词： Galvalume alloy directional solidification microstructure length scale microhardness

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Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy

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China Foundry 2024年第1期21卷 11-19页

作者： Wen-ning Liu Wei Zhang Peng-yue Wang Yi-xian Liu Xiang-yi Jiao Ao-xiang Wan Cheng-gang Wang Guo-dong Tong Shou-mei Xiong School of materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced materials Processing Technology Tsinghua UniversityBeijing 100084Beijing China FAW group Co. Ltd.Changchun 130013China China FAW Foundry Co. Ltd.Changchun 130013China

The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg *** AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg *** elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-*** a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and *** an increase in slow shot speed,the size and number of ESCs and porosities significantly *** addition,the distribution of ESCs is more dispersed and the net-shrinkage *** tensile property is greatly improved by adopting a higher slow shot *** ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).

关键词： hypoeutectic Al-Si alloy high pressure die casting porosity externally solidified crystal tensile property

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