JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 100
·期 2
·686-696
·
IF 2.787
Qingqing Yang,Bin Meng,Zuoliang Lin,Xinkun Zhu,Feng Yang,Shan Wu
To further enhance the electrical conductivity of doped ceria, the samarium-doped ceria (SDC)/Al 2 O 3 nanocomposites were prepared through sintering the coprecipitated powders in 1100°C-1300°C. The grain sizes of all composites are less than 100 nm and decrease with alumina addition. Besides the main phases of SDC and Al 2 O 3 , the SmAlO 3 can precipitate in the composites if sintered at higher temperatures or for longer dwell time. The deviations of SDC diffraction peak positions demonstrate the solid solution of alumina into SDC lattice. The total electrical conductivities of the composites increase with alumina content until 30% alumina is added. The SDC/30%Al 2 O 3 presents the higher total conductivity than the pure SDC by about five times. Specifically, the grain interior conductivity generally decreases with the alumina addition while the grain-boundary conductivity increases with that. The introduction of the conductive SDC/Al 2 O 3 interface can contribute to the rise of total conductivity, yet the excessive alumina addition also blocks the oxygen ion conduction. The SmAlO 3 precipitation is detrimental to the ion conduction for it consumes part of alumina and leads to the decrement in Sm concentration of SDC grain. Appropriate alumina addition not only enhances the conductivity of SDC but also lowers the material cost.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2020
·Vol. 150
·期 11
·3174-3183
·
IF 2.482
Wang Xun-Qiang,Li He,Yuan Qi-Yue,Liu Xiao-Qin,Liu Ding-Hua
Abstract Polycarbonate diols (PCDLs) are intermediates used in the synthesis of polyurethanes (PU), and therefore their efficient and green synthesis is a necessity. In this work, KOH/K 2 CO 3 @ γ -Al 2 O 3 catalysts were prepared and employed in the synthesis of PCDLs. A 4 wt% KOH/40 wt% K 2 CO 3 @ γ -Al 2 O 3 catalyst and a DMC: 1,4-BDO molar ratio of 1.25:1 exhibited the best activity for the reaction and gave a PCDL yield of 95% with a molecular weight of 4527 g·mol −1 . Moreover, the catalyst could be reused 4 times without a significant loss of the catalytic activity in transesterification. The effects of the catalyst composition and reaction conditions on the synthesis of PCDLs were investigated. The results indicate that the catalyst amount and the molar ratio of DMC: 1,4-BDO can influence the purity of PCDLs. Graphic Abstract The reaction equation
Catalyst preparation
The synthesis of PCDLs using DMC and 1,4-BDO
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2025
·Vol. 15
·期 6
·4443-4457
·
IF 4.6
Junqi Zhang,Yongwang Li,Zhiwei Zhang,Zheng Wang,Jiaxing Zhang,Shuai Liu,Yang Qin,Bingxin Zhu,Tongxue Zhang,Hongyu Wang,Fumin Wang,Xubin Zhang
The development of simple, efficient and economical catalysts for the hydrogenation of biomass to produce high value-added chemicals is of great significance in solving the energy crisis. In this work, a series of non-precious metal catalysts (Cu–Al2O3–ZnO) with different defect sites were prepared by etching Devarda's alloy. Under optimized mild reaction conditions, the furfural conversion and furfuryl alcohol selectivity are both greater than 99.0%, and the catalyst has good reusability. Characterisation and experiments were used to investigate the activate species for hydrogenation reaction. It can be proved that the low-valent Cu species in the Cu–Al2O3–ZnO catalysts play an important role as adsorption and dissociation sites for H2. Different etching degrees and sample reduction temperatures of the alloy can be used to adjust the content of acidic sites such as Al2O3 and CuO, which have appropriate adsorption properties for furfural. ZnO promotes the dispersion of the Cu species and enhances the accessibility of the active sites. The etching method achieves the interaction between species to further enhance the stability and activity of the catalyst. The catalytic performance of the catalyst is very competitive and this study provides a new method for the efficient hydrogenation of furfural to furfuryl alcohol.
研究领域:
化学工程
·
可再生能源
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Crystals
·
2023
·Vol. 13
·期 8
·1261
·
IF 2.7
Zhen Pei,Haixiao Huang,Xingzhong Guo,Jinming Zhang,Mingxing Chen
MgO–Al2O3–SiO2(MAS) glass–ceramics with controllable crystalline phases were successfully prepared using the melting method followed by heat treatment. The effects of the main components of glass on the crystallisation kinetics, nucleation, crystallisation and properties of glass–ceramics were investigated in detail. As the Al2O3and MgO contents increase and SiO2content decreases, the crystallisation peak temperature and activation energy of MAS glass decrease, while the crystal growth tends to follow a homogeneous nucleation crystallisation. The MAS glass nucleation temperature and time increase with higher concentrations of Al2O3and MgO and with a lower SiO2concentration. Mg2(Al4Si5O18) indialite and MgAl2O4spinel precipitate simultaneously in the MAS glass after crystallisation; the relative proportion of crystalline phases is related to the composition and crystallisation temperature. A higher SiO2content allows the formation of a dominant indialite phase, while higher MgO and Al2O3contents promote the formation of a dominant spinel phase. The MAS glass ceramic with a greater indialite phase has good dielectric properties with a dielectric constant of 6.499 and dielectric loss of 0.0064, while that of a higher spinel phase possesses improved mechanical properties, with a Vickers hardness of 715 Hv and a bending strength of 244.9 MPa.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2022
·
IF 5.518
Jisheng Yang,Han Li,Zede Yi,Murong Liao,Zhiyong Qin
Superhydrophobic treatment of wood is of great significance for improving the service life of wood and expanding its application fields. In this study, two process methods were designed to meet above requirements. Using polydopamine (PDA), 3-mercaptopropyltriethoxysilane (KH580) and nano-Al 2 O 3 as the micro-nano structure maker and octadecyltrichlorosilane (OTS) as a low surface free energy agent to modify rough surface in order to prepare superhydrophobic wood samples (Wood@One-step and Wood@Two-step). The contact angle (CA) and sliding angle (SA) of the Wood@One-step were 155.3° and 4.76°, respectively; the CA and SA of the Wood@Two-step were 152.9° and 7.65°, respectively. Surface electron microscopy (SEM) images showed that the surface of Wood@One-step and Wood@Two-step were honeycomb structure and layered stacking structure respectively. The superhydrophobic properties of Wood@One-step were superior because of its more reasonable micro-nano roughness. Atomic force microscope (AFM) images presented that the nano-Al 2 O 3 particles could effectively provide nano-level roughness. X-ray photoelectron spectroscopy (XPS) analysis showed that KH580 had covalent interaction with PDA. Thermogravimetric (TG) analysis, the immersion of acid-base solution and organic solution revealed that obtained superhydrophobic wood samples had excellent stability in the face of environmental challenges.
研究领域:
材料科学
·
木材科学
·
表面化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 15
·6354-6364
·
IF 3.5
Zhu Qijing,Zhang Chaoyun,Peng Xiaoling,Li Jing,Wu Qiong,Xu Jingcai,Hong Bo,Wang Xinqing,Ge Hongliang
Amorphous FeSiB/Al 2 O 3 soft magnetic composites were successfully fabricated in this work by applying an external magnetic field perpendicular or parallel to the magnetic toroidal surface, aiming to investigate the influences of magnetic field orientation on their structures and magnetic properties. The results indicate that amorphous FeSiB particles can form chain-like clusters aligned parallel to the direction of the applied magnetic field, which effectively reduces the magnetic reluctance along this direction. The magnetic toroidal with parallel orientation exhibits the highest effective magnetic permeability of 23.8 and a magnetic loss of 43.693 kW/m 3 at 590 kHz and 10mT, which is superior to both the non-oriented and perpendicularly oriented ones due to its optimized microstructure that reduces magnetic reluctance along the working circuit.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
JACS Au
·
2025
·
IF 8.7
Xuan Bie,Yukun Pan,Xiaowei Wang,Shiyu Zhang,Jiahui Hu,Xiaoxiao Yang,Qinghai Li,Yanguo Zhang,Robert E. Przekop,Yayun Zhang,Hui Zhou
Gas sources rich in CO2 derived from biomass/waste gasification, anaerobic digestion, or industrial carbon capture often contain impurities such as H2S, H2O, and NH3, which can significantly hinder catalyst performance. Here, we show the role of NH3 on the reverse water–gas shift (RWGS) reaction over a commercial Cu/ZnO/Al2O3 catalyst, examining its effects on both the catalytic activity and the catalyst structure. We found that NH3 reversibly decreases CO2 conversion immediately by suppressing carbonate hydrogenation and CO desorption. This effect intensifies with an increase in NH3 concentration but decreases at higher temperatures. However, prolonged exposure (over 100 h) to RWGS conditions in the presence of 1.4% NH3 leads to near-total and irreversible deactivation of the Cu/ZnO/Al2O3 catalyst. Under NH3 exposure, the catalyst loses Cu+ sites on the surface, causing a spatial separation of Cu and ZnO. Finally, to address this challenge, we propose a novel strategy to mitigate NH3 inhibition by decomposing NH3 into N2 and H2.
研究领域:
化学工程
·
催化科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE RESEARCH
·
2012
·
IF 2.332
Liqiang Wu,Zhikui Yin
A simple and clean synthesis of per- O -acetylation carbohydrate derivatives has been accomplished by treatment of sugars with a stoichiometric quantity of acetic anhydride under solvent-free conditions in the presence of sulfonic acid functionalized nano γ-Al 2 O 3 as an efficient and environmentally benign catalyst.
研究领域:
有机化学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER BULLETIN
·
2020
·Vol. 78
·期 10
·5891-5903
·
IF 2.014
khan Muhammad Zeeshan,Wang Feipeng,Waleed Aashir,Huang Zhengyong,Hassan Muhammad Arshad Shehzad,Khan Asim
In this work, epoxy resin samples incorporated with nano-Al 2 O 3 of various concentrations 0, 1, 3 and 5 wt% were prepared. Surface treatment of nano-Al 2 O 3 was performed by the saline coupling agent of γ-aminopropyltriethoxysilane (KH550) to restrict the aggregation. The thermal gravimetric analysis (TGA) of the epoxy resin/Al 2 O 3 nanocomposites was observed at different filler concentrations. TGA analysis indicated that incorporation of nano-Al 2 O 3 increases the decomposition temperature as compared to pure epoxy resin. Moreover, 3 wt% filler concentration showed increased decomposition temperature because nanoparticles form close connections between molecules due to which thermal stability improved at higher temperatures. Atomic force microscopy was employed for the surface morphology of epoxy resin/Al 2 O 3 nanocomposites which has indicated that surface roughness of epoxy resin/Al 2 O 3 nanocomposites increased slightly with the filler concentration. The distribution of trap energy and trap density obtained by isothermal surface potential decay measurements revealed that 1 wt% filler concentration results in decrease in surface potential decay rate. In addition, significant increase in deep trap energy level and trap density was obvious at 1 wt% filler concentration. AC and DC breakdown strength of the samples was measured to evaluate the effect of filler concentrations on the electrical characteristics of epoxy resin. The results showed that breakdown strength of the epoxy resin/Al 2 O 3 nanocomposites increases with the nano-Al 2 O 3 concentration. Moreover, increase in trap energy results in an increase in the breakdown strength of the nanoparticles.
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL ENGINEERING SCIENCE
·
2022
·Vol. 39
·期 1
·56-63
·
IF 2.172
Jie Zhang,Ben Dong,Jing Liu,Wuxu Yang,Sijie Ge,Shilong He
In this article, Mn doping on Ce-based γ-Al2O3 (i.e., Mn-Ce-γ-Al2O3) was synthesized and then employed as catalysts to study the removal of phenol from aqueous solutions through catalytic ozonation process. The results showed that the phenol removal was remarkably increased to 97.50% if Mn-Ce-γ-Al2O3 was adopted as the catalyst. In addition, the kinetic rate of the reaction was increased, approximately, about 1.49 times when using Ce-γ-Al2O3 catalyst with Mn doping. Moreover, X-ray diffraction, transmission electron microscopy, Brunner-Emmet-Teller measurements, and X-ray photoelectron spectroscopy techniques were used to comprehensively characterize the physicochemical properties of the synthesized Mn-Ce-γ-Al2O3 catalyst, including the phases, morphologies, textural properties, and dispersity of the surface active species. More uniform channel mesoporous structures were obtained after Mn doping on Ce-γ-Al2O3, which could enhance the gas-liquid mass transfer rate, surface hydroxyl groups, Ce3+/Ce4+ ratio, and the formation of Mn-Ce solid solution. In this study, the effects of Mn doping on Ce-based γ-Al2O3 on phenol degradation were investigated and the removal mechanisms were suggested for a better understanding of the improved removal efficiency.
研究领域:
环境科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2018
·
IF 4.427
Wei Zhang,Shilu Zhang,Jing Wang,Meng Wang,Qiulai He,Jianyang Song,Hongyu Wang,Jinping Zhou
In this study, we prepared a novel hybrid functionalized chitosan-Al 2 O 3 @SiO 2 composite (FCAS) for removing hexavalent chromium [Cr(VI)] from aqueous system. Spectroscopic studies like Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive spectroscope (EDS) were characterized. The effects such as dosage of adsorbent, pH, contact time and initial Cr(VI) concentration were evaluated. It has been illustrated that a wide acidic condition in the pH range of 2–6 was conducive to Cr(VI) adsorption and only 10 min was required to reach about 80% adsorption. Also, the adsorption properties of prepared adsorbent such as kinetics, thermodynamics and isotherms were comprehensively studied. Additionally, the adsorption capacity barely declined even after five cycles. Studies found that FCAS with characteristics of high performance of adsorption rate and capacity and better reusability would be a potential adsorbent for wastewater treatment .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Chenxu Liu,Shuguang Zhang,Ruonan Ji,Peng Wang,Jin Zhang,Yu Tian,Yonggang Meng,Yedong He
Semiconductor particles doped Al 2 O 3 coatings were prepared by cathode plasma electrolytic deposition in Al(NO 3 ) 3 electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7 µm and 40 nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5 g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5 g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction . The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings.
研究领域:
材料科学
·
表面工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）