International Journal of Applied Ceramic Technology
·
2020
·Vol. 17
·期 5
·2094-2103
·
IF 1.762
Kangkang Yuan,Xiaotong Jin,Xinqiang Wang
In this work, MgO-ZrO 2 and MgO-6YSZ ceramic fibers were prepared with sol-gel method via electrospinning. Polymorph stability and microstructure evolution of zirconia fibers were fully characterized by X-ray diffraction, Raman spectra, X-ray photoelectron spectroscopy, and Scanning electron microscope. The results indicated that tetragonal zirconia for MgO-ZrO 2 was obtained and cubic zirconia could be fully stabilized for MgO-6YSZ with MgO molar fractions varying from 0.1 to 0.5 at 800°C. Monoclinic phase appeared with MgO molar fractions even up to 0.5 for MgO-ZrO 2 system and partially or fully stabilized zirconia could be achieved for MgO-6YSZ at 1000°C and 1200°C. Grain size was gradually decreased with increasing of MgO content at 800°C both for MgO-ZrO 2 and MgO-6YSZ ceramic fibers. The grain size of both systems increased with MgO molar fractions varying from 0.1 to 0.2 and then decreased at higher contents at 1000°C and 1200°C. A discussion on relationship among MgO state and the phase stability and grain size was presented. This work shows surface excess and solid solution of MgO predominantly controlled the phase stability and microstructure evolution of zirconia fibers.
研究领域:
材料科学
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陶瓷材料
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yilin Zhao,Shenghua Liu,Xiaoqian Feng,Jiaxin Wang,Lijiao Chen,Yonghua Zhao,Huan Wang,Qijian Zhang
Dry reforming of methane (DRM) is a promising pathway to convert greenhouse gas into syngas. However, the commonly used Ni based catalysts suffer deactivation due to severe sintering and coking. In this paper, a series of porous Ni/MgO-ZrO 2 catalysts (5Ni/xM(1-x)Z, x = 0, 20, 40, 60, 80 wt%, respectively) with high specific surface area were synthesized by a facile combustion method followed by incipient impregnation. It is found that the appropriate amount of MgO (40 %) addition in ZrO 2 favors high porosity and high specific area. More MgO enhances the basicity of the catalyst as well as the metal-support interaction (MSI) by the formation of NiO-MgO solid solution, thus improving DRM activity and coking resistance. However, excessive MgO addition leads to over-strong MSI and lower porosity, resulting in lower DRM activity. The catalyst with 40 % MgO addition (5Ni/40M60Z) exhibits the best activity (conversions of CH 4 ∼ 76 %, CO 2 ∼ 83 %) and stability (>50 h) at high GHSV = 96000 ml/g cat ·h and 750 °C. in situ DRIFTS reveals the mechanism that MgO addition improves DRM activity and stability. Compared with ZrO 2 where CO 2 adsorbs as monodentate carbonate, CO 2 tends to adsorb on 40 %MgO-60 %ZrO 2 as bidentate carbonate and then easily transfer to more stable intermediate bidentate formate, thus improving DRM activity and coking resistance. This study provides new insights on the role of Mg addition in Ni/MgO-ZrO 2 DRM catalysts.
研究领域:
催化化学
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材料科学
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能源化学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
·
IF 4.539
Fulong Cheng,Fangui Nie,Changxin Zhao,Wei Li,Jie Pan
Excessive phosphorus is regarded as one of the main causes of eutrophication, destroying the balance of the original ecosystem of water bodies and endangering human health. In this study, a novel MgO/ZrO 2 composite oxide with a hollow structure (MgZr-CS) was prepared by a simple carbon template method, and served as an adsorbent for the efficient uptake of phosphate from aqueous solutions. For comparison, MgO/ZrO 2 bimetal oxide (MgZr) was also prepared by the conventional co-precipitation method. The effects of pH and coexisting anions on the adsorption of phosphate were studied. The adsorption performance of materials was described by the adsorption kinetic model and isothermal model. The adsorption capability of both MgZr-CS and MgZr was negligibly affected by coexisting ions (e.g., Cl − , NO 3 − , HCO 3 − and SO 4 2− ) in water. The adsorption kinetic of both MgZr-CS and MgZr was better correlated with the pseudo-second-order kinetic model , while the adsorption isotherm followed the Langmuir model. However, the Langmuir maximum phosphate adsorption capacity of MgZr-CS was 149.3 mg/g at initial pH of 7, which was about twice that of MgZr. Remarkably, different from MgZr that only presented well phosphate adsorption performance under the acidic environment, MgZr-CS could maintain the excellent adsorption performance within a particularly wide pH range of 3–11. Compared to adsorbents reported in previous papers, MgZr-CS also exhibited larger adsorption capacity and higher pH stability. Moreover, MgZr-CS performed prominent in the treatment of actual domestic sewage, and its phosphate removal rate could reach 99.3%. The adsorption mechanism analysis revealed that the excellent phosphate performance of MgZr-CS was mainly due to the existence of oxygen vacancies providing more active adsorption sites. Results shown here indicated that MgZr-CS can be used as a potential adsorbent for phosphate.
研究领域:
环境科学
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水处理
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材料科学
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化学工程
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产品关联
DOI
高影响因子
ACS Applied Nano Materials
·
2022
·
IF 6.14
Lijing Zhang,Jiaqi Han,Yuchao Wang,Wenbo Yang,Shengyang Tao
Achieving a room-temperature Suzuki–Miyaura coupling (SMC) with high efficiency is of great significance to the development of low-carbon organic synthesis. Nevertheless, it is still a great challenge to construct a promising nanocatalyst with high activity for room-temperature SMC reaction. In this paper, a strong alkaline-supported nanocatalyst Pd/Mg(OH)2/MgO–ZrO2 was rationally developed based on MgO–ZrO2 hybrid nanofibers. Physicochemical characterizations present that the in situ conversion of MgO to Mg(OH)2 on the surface of the nanofibers results in a great increase in surface alkalinity of the carrier. The strong alkalinity can greatly accelerate the oxidation addition and transmetalation of the SMC process, resulting in the obvious reduction of activation energy of the reaction (Ea = 9.0 kJmol–1 for Ph–Br). The coupling conversion can reach up to 100% at room temperature within 8 min with a maximum TOF > 6516 h–1. It also shows an excellent performance in substrate applicability and chlorobenzene activation. The rational design of a high-basicity catalyst for room-temperature SMC will be a rewarding attempt for the development of low-carbon green organic synthesis.
研究领域:
催化化学
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有机合成
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纳米材料科学
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
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2016
·Vol. 51
·期 17
·8139-8147
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IF 2.302
Sun W. Z.,Cheng J. G.,Huang Z. K.,Jiang Y.,Wu L. E.,Liu L. M.
When MgO+ZrO 2 were used as a sintering aid to SiC ceramics, it was found that ZrO 2 reacted with SiC and MgO to form ZrC and a magnesium silicate. This reaction may provide a new route to synthesize ZrC or prepare ZrC/SiC composites by reaction sintering using ZrO 2 , SiC, and MgO as starting materials. In the present work, formation process of the ZrC phase in the SiC–MgO–ZrO 2 system was addressed. Subsolidus phase relations at 1550 °C of the SiC–MgO–ZrO 2 system and the related SiC–SiO 2 –ZrC–ZrO 2 –MgO (Si–Zr–Mg–O–C) system were investigated.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2021
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IF 6.901
Na Li,Yaru Peng,Zeng Chen,Wenjuan Xiong,Jiaqi Sun,Yiming Chen,Putao Zhang,Meiyue Liu,Shengjun Li
The electro-deoxidation of MgO does not proceed efficiently due to the electrical insulation properties of MgO and large molar volume of metallic magnesium. In this experiment, an attempt was done to prepare Mg-Zr alloy from their oxides using the method of electro-deoxidation. The electrochemical mechanism of the deoxidation process of MgO, ZrO 2 and MgO-ZrO 2 composite was studied through cyclic voltammetry using metallic cavity electrode (MCE). There was an intermediate phase (Zr 3 O) in the reduction process of ZrO 2 . The electro-deoxidation of MgO occurred for MgO-ZrO 2 composite in CaCl 2 -NaCl molten salt. Moreover, the electro-deoxidation of MgO was promoted by the addition of polyvinyl butyral (PVB). The formation of metal phase Mg was confirmed by XRD, EDS, Raman spectroscopy, and inductively-coupled plasma spectroscopy. The electro-deoxidation products showed significant differences with the concentration of PVB and the ratio between MgO and ZrO 2 . The electro-deoxidation of MgO and ZrO 2 was favorable when the PVB concentration was 5.0% (wt.%). Pure metal phase of Mg-Zr alloys was formed when the molar ratio of MgO and ZrO 2 was 1:2. The atomic fraction of Mg in the electrolytic product was ca. 28.0 mol.%. This work shows that MgO could be directly electro-deoxidized to Mg without the formation of intermediate phase oxide.
研究领域:
材料科学
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冶金工程
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无机化学
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电化学
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金属合金制备
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DOI
高影响因子
ChemistrySelect
·
2025
·Vol. 10
·期 33
·e03026
·
IF 2
Yongzhao Zhang,Yunlei Zhou,Jiahang Wang,Heng Ban,Rongjie Xu,Junhao Pan,Fusheng Ge,Zhenya Zhu,Luping Lyu
Graphical MOFs-templated MgO/ZrO 2 enable highly selective glucose-to-fructose conversion. Structural confinement suppresses MgO agglomeration and tunes basicity, achieving 38.4% yield with 90.9% selectivity. High-selectivity glucose isomerization to fructose is essential for the biorefinery industry and fructose syrup production. In this work, a catalyst with tailored basicity was synthesized via the calcination of a MOFs (metal-organic frameworks)-based composite and employed as a chemo-catalyst for glucose isomerization, achieving high fructose selectivity. Characterization results confirmed that the synthesized catalyst was a composite consisting of and MgO, with MgO highly dispersed within the channels of . The MOFs templating effect restricted particle size and minimized agglomeration of MgO particles, enhancing the interaction between MgO and . This strong interaction effectively modulated the basicity of the catalyst, resulting in the predominance of weak basic sites. As a result, the catalyst demonstrated superior performance in glucose isomerization, achieving a 38.4% fructose yield with 90.9% selectivity at a 10 wt% glucose concentration, outperforming catalysts prepared by conventional methods. However, leaching remains a challenge. This work presents a novel approach for synthesizing highly dispersed mixed oxides and provides an effective catalyst for glucose isomerization.
研究领域:
催化
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材料科学
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化学工程
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绿色化学
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生物炼制技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）