JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
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IF 5.7
Gui Li,Jianjie Hao,Jiayan Li,Pengyu Dai,Bo Wang,Yuanqi Li,Yi Tan,Xueqiang Cao
This work firstly evaluated the effect of temperature on the preparation of SiC coating using Al 2 O 3 as catalyst by pack cementation (PC) method. SiC/ZrB 2 -SiC-Si (ZSS) and SiC/ZrB 2 -SiC-Al 2 O 3 (ZSA) coating were prepared on the surface of C/C composites by PC combined with atmospheric plasma spraying (APS). The objective of this work is to study the influence of Si and Al 2 O 3 additives for ablation performances of ZrB 2 -SiC coating. The coated samples were subjected to ablation test, and the phase composition and microstructure evolution were investigated. The results indicated that SiC/ZSA coating had better ablation resistance because phase transformation and growth of ZrO 2 grain was restrained by Al 2 O 3 .
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CERAMICS INTERNATIONAL
·
2019
·Vol. 45
·期 18
·24851-24857
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IF 3.45
X.Y. Ping,Q.Q. Yang,B. Meng,W.K. Liang,Q. Zheng,Z.D. Xia,H. Zhang
The polycrystalline Ce 0.85 Y 0.15 O 1.925 (YDC)-xmol%Al 2 O 3 (x=0, 5, 10, 20, 30) composite ceramic was sintered and prepared at 1300 ° C for 10 h in the air atmosphere to investigate the effects of the YDC/Al 2 O 3 heterogeneous interface on its electrical conduction properties. The main phase of YDC exists in all samples, and the second phase of Al 2 O 3 starts to appear in the XRD patterns when its content is beyond the solid solubility limit in YDC. No severe reaction between YDC and Al 2 O 3 occurs in the composite samples at 1300 ° C. The average grain size of the composite ceramics decreases from 510 nm to 330 nm with the rise in Al 2 O 3 content from 0 to 30%. The specific grain boundary electrical conductivity of YDC-xAl 2 O 3 samples decreases with the Al 2 O 3 content from 0 to 20% and then begins to increase when the Al 2 O 3 content rises from 20% to 30%. The YDC-30%Al 2 O 3 sample shows a higher specific grain boundary conductivity than YDC-20%Al 2 O 3 , which mainly originates from the higher volumetric fraction of YDC/Al 2 O 3 heterogeneous interface in YDC-30% Al 2 O 3 as well as the higher oxygen ion mobility in YDC/Al 2 O 3 heterogeneous interface region.
研究领域:
材料科学
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陶瓷学
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固体离子学
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电子陶瓷
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JOURNAL OF CATALYSIS
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2025
·
IF 6.5
Wenhao Zhang,Liang shen,Longhao Xu,Fayang Zhou,Fengyin Sun,Jing Xu,Minghui Zhu
Hydrogenation of CO 2 to methane is a feasible solution to the growing global environmental and energy challenges. Nickel-based catalysts are efficient and cost effective for CO 2 methanation. Hernin, we synthesized Mn-promoted Ni/Al 2 O 3 catalysts with facilitated CO 2 methanation and elucidated the crucial role of Mn. After Mn doping, NiMn/Al 2 O 3 catalysts showed improved NiO dispersion. Subsequently, H 2 reduction and CO 2 methanation treatments resulted in reduction of NiO and MnO 2 into Ni and MnO, and incorporation of Ni 2+ into MnO lattice, forming NiMnO x and creating numerous Ni-NiMnO x interfaces. The abundant oxygen vacancies from NiMnO x could enhance CO 2 activation. Moreover, oxygen vacancies at the interface also promote electron transfer from Ni and MnO, leading to electron-poor Ni nanoparticles and thus significantly promoting the *CO methanation. Ultimately, the electron-poor Ni nanoparticles and abundant oxygen vacancies at the Ni-NiMnO x interface jointly facilitate CO 2 methanation.
研究领域:
催化化学
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环境科学
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能源科学
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CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Chenguang Li,Chenbiao Lai,Yaoyan Wu,Hanxiang Ouyang,Junbin Sun,Weihong Lu
Alumina based rare earth oxides ceramic materials, with the good performance against the CMAS corrosion, were widely used as the thermal/environmental barrier coatings. In this work, three Y 2 O 3 –Al 2 O 3 binary ceramic bulks, which were the Y 3 Al 5 O 12 , YAlO 3 and Y 4 Al 2 O 9 , were prepared by high temperature solid state reaction using the Y 2 O 3 and Al 2 O 3 as the raw materials. The resistances to CMAS corrosion of these materials at 1250 °C and 1350 °C were compared fully. The compositions and structures of the samples before and after corrosion were analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Results showed that the different chemical compositions of the materials resulted in the different optical basicity (OB) values which can decide the reactivity of the material with the CMAS melts. The Y 3 Al 5 O 12 ceramic material was inert to the CMAS for its low OB value of 0.75 and damaged seriously by the CMAS through physical penetration. The YAlO 3 and Y 4 Al 2 O 9 with the high OB values of 0.80 and 0.87 reacted with the CMAS to form the Ca 4 Y 6 (SiO 4 ) 6 O. The YAlO 3 ceramic bulk exhibited the good performance against the CMAS corrosion benefitting from the formation of the Ca 4 Y 6 (SiO 4 ) 6 O and the CaAl 2 Si 2 O 8 .
研究领域:
材料科学
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化学
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2026
·
IF 3.5
Hongda Zhang,Jinyan Hu,Shuting Bao,Shichao Su,Weiyao Yang,Le Sang
Designing efficient catalysts and solvent system for the multiphase hydrogenation reaction is vital in continuous flow reactors. Herein, we prepare hydrophilic Pd/Al 2 O 3 and hydrophobic modified C 12 PA-Pd/Al 2 O 3 catalyst for nitrobenzene (NB) hydrogenation in micropacked bed reactors (μPBRs). By tuning the methanol-water volume ratio, reaction temperature, reaction pressure, liquid and gas superficial velocity, the NB conversion and aniline (AN) yield are optimized. The highest NB conversion of 97.1% and AN yield 95.6% are obtained in μPBRs with hydrophobic C 12 PA-Pd/Al 2 O 3 at the reaction temperature of 90 °C. The apparent kinetic model is developed in μPBRs with two types of catalysts, and activity energies of NB hydrogenation for Pd/Al 2 O 3 and C 12 PA-Pd/Al 2 O 3 are 7.944 kJ·mol -1 and 3.372 kJ·mol -1 , respectively. It indicates that the catalytic efficiency of C 12 PA-Pd/Al 2 O 3 is better than that of Pd/Al 2 O 3 in the methanol-water mixed solvent in μPBRs. The value of TOF for the hydrophobic modified C 12 PA-Pd/Al 2 O 3 catalyst is twice compared with the hydrophilic Pd/Al 2 O 3 catalyst. The value of STY for μPBRs is higher than that of stirred tank reactors (STRs) and fixed bed reactors (FBRs).
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2023
·
IF 3.8
Qinqin Yuan,Jingyue Liang,Wei Li,Jinli Zhang,Cuili Guo
Anthraquinone hydrogenation to produce H 2 O 2 is an economically interesting reaction with great industrial importance. Here, we report a series of Pd/ x Al catalysts with different AlCl 3 contents by a conventional stepwise impregnation method. The optimal Pd/1.0Al catalyst exhibits a higher performance toward anthraquinone hydrogenation with 8.3 g·L −1 hydrogenation efficiency, 99.5% selectivity and good stability, obviously superior to that of Pd/Al 2 O 3 catalyst (5.2 g·L −1 and 97.2%). Detailed characterization demonstrates that AlCl 3 can be grafted on the γ-Al 2 O 3 support to obtain a modified support with abundant surface weak acid and Lewis acid, which can adsorb and activate anthraquinone. Meanwhile, its steric hindrance could isolate and disperse active metals to form more active sites. The synergies between metal sites and acid sites promotes the anthraquinone hydrogenation. Furthermore, the good stability after grafting AlCl 3 could attribute to the enhanced metal-support interaction inhibiting metal particles agglomeration and leaching.
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RARE METALS
·
2018
·Vol. 42
·期 11
·3870-3876
·
IF 1.5
Ji Ruo-Nan,Liu Chen-Xu,Zhang Jin,Zhang Shu-Guang,Zhang Le,Lian Yong
Al 2 O 3 /polytetrafluoroethylene (PTFE) composite coating was prepared on titanium alloy by cathode plasma electrolytic deposition (CPED) and impregnation method, to improve the hydrophobicity and tribological properties. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analysis of the coating indicate that PTFE penetrates into the interior of the coating and is well bonded to titanium alloy substrate by cross-linking with Al 2 O 3 ceramic coating. The contact angles were measured by contact angle measurement, and the tribological properties of the composite coating were evaluated by sliding wear test. The surface of the composite coating is found to possess good hydrophobicity with a water contact angle of 140°. The results also indicate an improved tribological properties of Al 2 O 3 /PTFE composite coating at room temperature with a steady friction coefficient as low as 0.05. The self-lubricating anti-wear composite coating is expected to solve fouling problems and poor wear resistance of titanium alloys.
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CONSTRUCTION AND BUILDING MATERIALS
·
2019
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IF 4.046
Xiaohai Liu,Baoguo Ma,Hongbo Tan,Hainan Li,Junpeng Mei,Ting Zhang,Pian Chen,Benqing Gu
The utilization of marine resources in reinforced concrete is severely limited, due to the risk of steel corrosion caused by the introduced chloride. In order to reduce this risk, nano-Al 2 O 3 (NA) was added into cement-based materials system by improving the chloride immobilization. The immobilized chloride ratio (ICR) of the system was evaluated, and the results indicated that the addition of NA could significantly enhance ICR. Based on the results from TG, XRD, 27 Al NMR, MIP, 29 Si NMR, and EDS, the mechanism behind was discussed from three aspects of chemical binding, migration resistance, and physical adsorption. The reasons for the increased ICR were as follows: a) chemical binding was promoted by increasing the amount of chloroaluminates; b) migration resistance was improved by refining the pore structure; c) physical adsorption, depending on the amount and the Ca/Si ratio of C-S-H gel, was reduced negligibly. These findings can provide guidance for the theoretical study of chloride immobilization and the application of marine resources.
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TRIBOLOGY LETTERS
·
2016
·Vol. 65
·期 1
·1-9
·
IF 1.758
Liu Xiaoyan,Wu Yicheng,Yu Zhiqiang
The tribological behaviors of epoxy composites filled with organic functionalized ZrB 2 –Al 2 O 3 were environmentally investigated and compared with those with as-received fillers under both dry and oil sliding conditions in this work. The worn surfaces and the transfer films on the counterparts were characterized by scanning electronic microscope (SEM), and the frictional temperature rising was investigated by infrared thermometer. The results demonstrated that the coefficient of friction (CoF), the wear rate, as well as the frictional temperature rise of the epoxy composites were all decreased due to the introduction of ZrB 2 –Al 2 O 3 fillers. And with the increase in filler content, similar variation tendencies of CoF and wear rate of epoxy composites were observed under the different sliding conditions. Besides, the organic functionalization of ZrB 2 –Al 2 O 3 fillers, which made the epoxy composites exhibit lower CoF and wear rate than those with as-received fillers, lowered the frictional temperature as well. In comparison, the epoxy composites filled with 5 vol% modified fillers presented better tribological properties, suggesting a stronger interfacial bonding between modified fillers and epoxy matrix. The dominant wear mechanisms of filled composites under dry and oil sliding conditions could be inferred as the combination of adhesive wear and abrasive wear and the fatigue wear, respectively, on the basis of SEM images of worn surfaces.
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FUEL
·
2025
·
IF 7.5
Hong-Hui Gong,Xian-Yong Wei,Wen-Long Mo,Zhi-Min Zong,Guang-Hui Liu,Pei Liu,Kun-Peng Jiao
NiCs/Al 2 O 3 with medium-strong alkaline and the contents of Ni and Cs of 26.55 wt% and 0.02 wt%, respectively, was prepared by a three-step method and characterized with multiple tools. Oxydibenzene (ODB) and benzyloxybenzene (BOB) were used as low-rank coal-related model compounds and their catalytic hydroconversion (CHC) were investigated over NiCs/Al 2 O 3. Under mild conditions (MCs), NiCs/Al 2 O 3 can effectively activate H 2 to biatomic active hydrogen (H···H) and part of H···H can be effectively split to relative mobile H - and immobile H + on the NiCs/Al 2 O 3 surface. Both ODB and BOB can be completely converted and full hydrogenation (FH) of the benzene ring (BR) in −O-BR is the first step for the CHC of both ODB and BOB via H···H transfer to the BR under MCs. Subsequently, H - transfer to an ipso -carbon (IC) in the resulting oxydicyclohexane from the FH of ODB cleaves an −O-CH< bond to produce cyclohexane (CH I ) and cyclohexyloxy anion (CHOA), which abstracts H + from H···H to afford cyclohexanol (CH II ) followed by H - transfer to the IC in CH II and subsequent HO – release to yield CH I . As a result, CH I is the only final product from the CHC of ODB. In contrast, H - transfer preferentially proceeds to the carbon atom in the –CH 2 - of the resulting benzyloxycyclohexane from the FH of the BR in −O-BR of BOB to produce toluene and CHOA followed by the FH of toluene to get methylcyclohexane and the H + abstraction by CHOA from H···H to obtain CH II . Moreover, NiCs/Al 2 O 3 shows a distinguished recyclability and repeatability.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2022
·
IF 3.898
Zhenyu Wu,Zengxi Li,Chunshan Li
The bare amorphous Al 2 O 3 -AlPO 4 and Cs/Al 2 O 3 -AlPO 4 catalysts were developed for the aldol condensation of methyl acetate with formaldehyde to methyl acrylate. The structure and property of catalyst were characterized by XRD, XPS, BET, Pyridine-IR, FT-IR, 27 Al-MASNMR, NH 3 -/CO 2 -TPD and SEM. The correlation between structural features and acid-base properties was established, and the loading effect of the cesium species was investigated. Due to cooperative catalytic effects between the penta-coordinated Al and Al 2 O 3 , the weak-II acid and medium acid site densities and the product selectivity were improved. While the basic site densities of these catalysts were almost in proportion to the conversion of methyl acetate. The loaded Cs could form new basic sites and change the distribution of acid sites which further enhance the catalytic performance. As a result, the 10Cs/8AlP was proved to be an optimal catalyst with the yield and selectivity of 21.2% and 85% for methyl acrylate respectively. During the reaction, a deactivation behavior was observed on 10Cs/8AlP catalyst due to the carbon deposition, however, it could be regenerated by thermal treatment in the air atmosphere at 400 °C.
研究领域:
化学工程
·
催化材料科学
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Wenjie Zhang,Jing Zhao,Linfeng Wang,Guofu Liu,Dekui Shen,Huiyan Zhang
The pyrolytic reforming of toluene to hydrogen and CNTs over the commercial and self-prepared Al 2 O 3 loaded with Fe through the impregnation method is investigated in a fixed bed reactor under the temperature from 600 °C to 800 °C. The physicochemical properties of Fe–Al 2 O 3 catalysts and Al 2 O 3 supports were characterized by XPS, H 2 -TPR, HRTEM and H 2 -pulse chemisorption . The reforming process over the catalyst of Fe loaded on self-prepared Al 2 O 3 gives the excellent H 2 yield of 27.8 mmol/(g-Fe) and graphite yield of 82.6 wt%, which is much higher than those from that over the catalyst of Fe loaded on the commercial Al 2 O 3 . It is evidenced by H 2 -pulse chemisorption that 5.1 % of Fe 0+ dispersion over the commercial Al 2 O 3 with mainly-exposed (110) facet while 11.2 % of Fe 0+ dispersion over self-prepared Al 2 O 3 with mainly-exposed (111) facet were obtained. The adsorption energy of iron cluster (Fe 4 ) with Al 2 O 3 (111) facet was estimated to be −14.5 eV through the DFT simulation, which is notably higher than that of iron cluster (Fe 4 ) with Al 2 O 3 (110) facet as −9.1 eV. With regard to the MD simulation along with XRD analysis of the Fe 3 C crystallite , Fe 0+ particles can be prominently molten at the high Fe 0+ dispersion over Al 2 O 3 facet, promoting the carbon solubility for the assembly of multi-wall CNTs without the deposition of unwanted amorphous carbon .
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