RSC Advances
·
2018
·Vol. 8
·期 25
·13728-13738
·
IF 2.936
Yongxian Zhou,Wei Chen,Pengfei Wang,Yimin Zhang
The low contact efficiency, large mass transfer resistance and high operational cost of traditional 13X molecular sieve particle adsorbents (MSPs) have greatly limited their application in deep purification of trace oxygenated compounds from gaseous olefins. Herein, we successfully fabricated dense and thin 13X molecular sieve membranes on a porous α-Al2O3 tube (MSCMs) by a combination of 3-aminopropyl triethoxy silane (APTES) surface modification and vacuum pre-coating sol technology for purifying the above impurities. By a solid–solution transformation process, 13X molecular sieve membranes on MSCMs that were continuous and integral without any cracks, pinholes or other defects, and mainly composed of 1–1.5 μm regular 13X crystals with a thickness of 5–6 μm have been achieved. The purification performance of the MSPs, non-APTES functionalized MSCMs (nMSCMs) and MSCMs was evaluated by dynamic adsorption of N2 or C2H4 feed flow containing dimethyl ether, methanol and propanal impurities at room temperature. The results demonstrated that both the nMSCMs and MSCMs could deeply purify the trace amounts of the three oxygenated compounds to below 1 × 10−6 (mol mol−1) from gaseous olefins at an initial concentration of 20 × 10−6 (mol mol−1), exhibiting much more excellent purification performance than that of MSPs. In particular, the breakthrough times of MSCMs for dimethyl ether, methanol and propanal were 7 h, 32 h and 51 h in a N2 system, and 12.1 h, 53 h and 90 h in a C2H4 system. The cumulative adsorption amounts of MSCMs for dimethyl ether, methanol and propanal were 12.108 mg g−1, 35.812 mg g−1 and 103.129 mg g−1 in a N2 system, and 25.88 mg g−1, 94.19 mg g−1 and 256.26 mg g−1 in a C2H4 system, respectively. The regeneration experiment also indicated that the MSCMs had a more stable structure and a longer lifetime. The excellent purification performance of MSCMs could be attributed to the continuous 13X molecular sieve layers without non-adsorption interfacial voids. Hence, the MSCMs have great potential for future industrial application of trace oxygenated compound removal from gaseous olefins.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2017
·
IF 4.601
Limo He,Song Hu,Long Jiang,Guang Liao,Liangping Zhang,Hengda Han,Xiaofang Chen,Yi Wang,Kai Xu,Sheng Su,Jun Xiang
Four types of biomass-derived organics (toluene/1-methylnaphthalene/phenol/ethanol) were catalytically decomposed and steam reformed over Ni/α-Al 2 O 3 for co-production of hydrogen and carbon nanotubes (CNTs). In the decomposition reaction, the oxygen functional group in phenol and ethanol promoted the co-production of hydrogen and CNTs, while a small amount of toluene and 1-methylnaphthalene were cracked to hydrogen and amorphous carbon. In the reforming reaction, the yields of hydrogen and CNTs sharply increased. More than 2000 mmol/(g-cata∗h) of H 2 and 260 mg/(g-cata∗h) of CNTs were produced after the reforming of toluene and ethanol. However, 1-methylnaphthalene was difficult to be reformed and small amount of CNTs were formed. The organics with low molecular weight and low degree of unsaturation conduced to the formation of hydrogen and CNTs. The growth of CNTs on Ni/α-Al 2 O 3 mainly follows the tip-growth mechanism. The diameter distribution of CNTs is not only influenced by Ni particle size, but also related to the different organics and steam addition.
研究领域:
能源化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Limo He,Song Hu,Xiaofei Yin,Jun Xu,Hengda Han,Hanjian Li,Qiangqiang Ren,Sheng Su,Yi Wang,Jun Xiang
Fe-modified Ni/Al 2 O 3 catalysts with Fe/Ni molar ratios of 0, 0.5, 1 and 2 were prepared to promote the co-production of H 2 and carbon nanotubes (CNTs) during steam reforming of toluene as a tar model compound. After the addition of Fe, toluene conversion increased from 55.1% of Ni/Al 2 O 3 to 73.6% of F1N1A (Fe/Ni ratio of 1), and H 2 yield over F1N1A reached the maximum of more than 2000 mmol/(g-cata). Multi-walled carbon nanotubes with average diameter of 10–30 nm were generated and follow tip-growth mechanism. Compared with Ni/Al 2 O 3 , the addition of Fe remarkably increased the amount and quality of CNTs which had longer length and less tortuosity. These dual promoting effects on H 2 and CNTs after the addition of Fe were attributed to the strong interaction between Ni and Fe in Fe-Ni alloy. Fe-Ni alloy had the high activity for the decomposition performance of toluene and H 2 O to generate more H 2 and intermediates for improving the reforming reaction. Meanwhile, the high catalytic decomposition activity supplied more carbon species and the formation of Fe-Ni alloy enhanced the generation of metal carbide for promoting CNTs growth. Besides, the deposition of amorphous carbon was suppressed and the interaction between Ni particle and catalyst support was weakened after the addition of Fe, which kept the activity of catalyst and promoted the tip-growth of CNTs.
研究领域:
催化
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材料科学
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化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Jia Shen,Chen Chen,Lichuan Song,Liding Zhong,Kai Shan,Yanglong Guo,Wangcheng Zhan,Yun Guo,Haifeng Wang,Li Wang
The anchoring effect between surface hydroxyls (–OH) and metal species has been extensively utilized to enhance catalyst stability. Nevertheless, few studies have investigated the impact of alloying process involving different types of –OH species. In this research, we discovered that the formation of the alloy particles Pt 3 Co was significantly influenced by the presence of distinct –OH species on Al 2 O 3 . Intriguingly, those Pt 3 Co alloy particles exclusively formed on α-Al 2 O 3 owing to the weak interaction between both Pt and Co species and the triply bridging hydroxyls (µ 3 -OH). In contrast, Pt and Co species were found to be separately dispersed on γ-Al 2 O 3 because of the strong anchoring effect of terminal hydroxyls (µ 1 -OH), especially for Co atoms. Density functional theory (DFT) calculations highlighted the difference in adsorption energies of the two metals on different hydroxyl groups, providing a theoretical rationale for the influence of hydroxyl groups on alloy formation. The presence of Pt 3 Co alloy resulted in a fourfold increase in the specific catalytic rate of Pt 3 Co/α-Al 2 O 3 in CO-PROX compared to Pt 3 Co/γ-Al 2 O 3 . Arguably for the first time, this study demonstrates the association between alloy formation and –OH groups, providing a unique perspective on the design of alloy catalysts.
研究领域:
催化化学
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材料科学
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理论计算化学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
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2015
·
IF 1.173
Shuguang Shen,Binbin Li,Meina Li,Jimin Fan,Zhijun Zhao
In order to find an effective method for urea removal from wastewater, a number of experiments were conducted in a batch reactor with α-Al2O3 and η-Al2O3 as catalysts, respectively. The results indicate that η-Al2O3 catalyst shows significantly higher urea removal rate than α-Al2O3 catalyst or the thermal hydrolysis, and the removal rate increases with increasing temperature, catalyst dosage and reaction time. Using η-Al2O3 catalyst, the urea concentration in wastewater is reduced to less than 1 mg/L at 165°C after 150 min. The reaction kinetics study shows that the hydrolysis of urea behaves as a pseudo-first-order reaction. From the calculated rate constants, η-Al2O3 exhibits an excellent catalytic activity for urea hydrolysis, whereas the activity of α-Al2O3 is considerably weak. In addition, the η-Al2O3 catalyst possesses good recycling ability. The slight loss of activity of η-Al2O3 should be attributed to the generation of a small amount of hydrated aluminas, and the activity can be recovered by calcination.
研究领域:
环境科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2021
·Vol. 99
·期 1
·169-177
·
IF 2.326
Cheng Ming,Liu Wensheng,Yao Shuwei,Wang Juan,Ma Yunzhu
Phase transformation is essentially important for the microstructures and properties of sol–gel prepared alumina fiber and powders. In this study, alumina precursor fiber and xerogels were prepared using the same aluminum carboxylate sol. The phase transformation and microstructure evolution of the precursor fibers and xerogels were investigated using TG-DSC, XRD, TEM, and SEM methods. The alumina precursor fiber and xerogels have similar chemical structures and Al(III) species. After preheated at 600 °C, most of the free water molecules, hydroxyl groups, nitrate acid radical, formic acid radicals, and acetic acid radicals are removed from the alumina precursor fiber and xerogels. The preheated fiber and xerogels exhibit amorphous phases. From the TG-DSC curves, the transformation temperature from γ-Al 2 O 3 to α-Al 2 O 3 in the preheated fiber is 30 °C lower than that in the preheated xerogels. The TEM results suggest that the fiber calcined at 1000 °C for 1 h can be completely transformed into α-Al 2 O 3 phase, while the xerogels need to be calcined at 1100 °C for 1 h to completely convert into the α-Al 2 O 3 phase. The difference in the phase transformation of the alumina fiber and xerogels was discussed in this paper.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Lijun Yang,Jiankun Liu,Yuxi Wang,Huanwen Zhou,Xiaoyuan Liao
In industry, silver-based catalysts are the mainstream choice for converting ethylene to ethylene oxide (EO), and the morphology of Ag particles plays an important role in their catalytic performance; however, related studies are scarce. In this work, evidence from SEM shown that we successfully synthesized three different morphologies of Ag particles induced by different solvent, i.e., flower-like Ag (Fl-Ag), spheroidal Ag (Sp-Ag) and sheet-like Ag (Sh-Ag), dissolve them respectively into the mixed solution of silver nitrate/oxalic acid to form a suspension, then load onto α-Al 2 O 3 . Through were calculated from the XRD peak area the Ag(100) surface occupancy has the order of Fl-Ag (30 %) > Sh-Ag (20 %) > Sp-Ag (15 %), and the selectivity of EO has positive relation with similar order of Fl-Ag/Al 2 O 3 (85 %) > Sh-Ag/ Al 2 O 3 (72 %) > Sp-Ag/Al 2 O 3 (70 %). The selectivity of Fl-Ag/Al 2 O 3 for EO at 210 °C was 85 %. It is shown that Ag(100) surface has better O 2 interaction and activated than that of Ag(111) surface, and (100) has a lower activation energy than the side reaction (0.9 eV vs 1.0 eV), facilitates the conversion of ethylene to ethylene oxide. This study provides a new method to design and optimize silver catalysts.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
SOLID STATE PHENOMENA
·
2018
·
IF 0
Min Wang,Zi Yuan Wang,Ya Jie Yuan,Wei Pan
The 8 wt.% yttria-stabilized zirconia (8YSZ) thermal barrier coatings (TBCs) are widely used to protect hot superalloy components of gas turbine and jet engine. However, Cracks and pores in the 8YSZ coating would accelerate the oxidation of the bondcoat alloy and the corrosion of 8YSZ topcoat by molten salts and finally result in permanent failure of the TBCs. Hence, in this work, a sol-gel spin-coating method was employed to prepare a dense α-Al2O3 film on the surface of air-plasma-sprayed 8YSZ coatings, in order to block the paths of cracks and pores while keeping the stress tolerance of 8YSZ coatings. The influences of the polyvinylpyrrolidone (PVP) and alumina content of the sol on the microstructure of the α-Al2O3 film were investigated. It is found that a sol with PVP addition amount of 50 mg/mL and alumina solid content of 10% let to the achievement of a compact α-Al2O3 film. The positive results in this work would inspire more efforts to prepare dense films on TBCs and therefore improve their performance under service conditions.
研究领域:
材料科学
·
表面工程
✓ 已验证
产品关联
DOI
RSC Advances
·
2015
·Vol. 5
·期 67
·54757-54761
·
IF 3.84
Songjie Fan,Shan Wu,Jianhua Liu,Dan Liu
The synthesis conditions of MIL-120 membranes supported by a-Al2O3 hollow ceramic fibers (HCFs) were studied systemically. The continuous and compact MIL-120 membranes were successfully synthesised by secondary growth with in situ seeding step. The MIL-120 membrane shows the separation factors of H2–CO2, H2–CH4 and H2–N2 are 9.4, 7.9, and 7.3 respectively at 293 K and 1 bar with H2 permeance of 3.5 × 10−7 mol m−2 s−1 Pa−1 as well as high thermal stability.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·Vol. 44
·期 10
·11374-11380
·
IF 3.057
Quanbin Li,Le Zhang,Shuai Wei,Yikun Zhang,Rong Sun,Tianyuan Zhou,Wei Bu,Qing Yao,Zhigang Jiang,Hao Chen
In this paper, weakly agglomerated and well dispersed α-Al 2 O 3 powders were synthesized by a novel spray precipitation method. It was demonstrated that the as-prepared powders exhibited better dispersity than powders from conventional precipitation due to the increased phase contact and reaction area during the precipitation process. The effects of different titration ways, calcination temperature and holding time on the morphology, phase composition and sintering behaviour of Al 2 O 3 powders were systematically investigated. Weakly agglomerated and well crystallized α-Al 2 O 3 powders were obtained when the as-prepared precursors were calcined at 1150 °C for 2 h in air. The average particle size of α-Al 2 O 3 powders with higher sintering activity was approximately 68.6 nm, and the specific surface area was above 22.4 m 2 g −1 .
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Qiyan Ji,Li Zhang,Xiuling Jiao,Dairong Chen
Alumina aerogels are desirable for lightweight and highly efficient thermal insulation. However, they are typically constrained by brittleness and structural collapse at high temperatures. The manufacture of alumina aerogels with ultralow thermal conductivity and excellent thermal stability at high temperatures beyond 1300 °C is still challenging. Herein, alumina aerogels with superior ultrahigh-temperature-resistant and thermal insulation were successfully prepared by assembling the α-Al2O3 nanosheets with silica sols as the high-temperature binders. Benefiting from the generation of the mullite-covered alumina biphasic structure, the α-Al2O3 nanosheet-based aerogels (ANSAs) exhibit excellent thermal and chemical stabilities even after calcination at as high as 1600 °C. The ANSAs had a low thermal conductivity (0.029 W·m–1·K–1 at room temperature), structural stability with a measured compressive strength of 0.6 MPa, and good thermal shock resistance. Furthermore, the 2D α-alumina@mullite core–shell sheets were also prepared as assembly units to construct aerogels (AMSAs). This core–shell structure can improve temperature resistance through inter-lattice suppression under continuous energy input at high temperatures. The AMSAs have a linear shrinkage of only 2.7% after calcination at 1600 °C for 30 min, further improving the temperature resistance, making them an ideal super-insulating material for applications at extremely high temperatures.
研究领域:
材料科学
·
热力学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2025
·
IF 9
Hammad Saulat,Weiquan Feng,Zhongzhuang Hu,Mengxing He,Jinming Lu,Yan Zhang,Jianhua Yang,Cheng He
Separation of butane isomers holds substantial importance across various industrial sectors due to their divergent chemical characteristics and pervasive applications. Their efficient separation into high-purity iso-butane (i-C 4 ) and normal butane (n-C 4 ) allows their optimal utilization while maximizing economic benefit and minimizing waste, though their separation presents significant challenges due to their similar physicochemical properties and energy-intensive separation requirements. Polycrystalline zeolite-based membrane separation processes emerge as an energy-efficient approach for separating butane isomers by reducing the total operating energy consumption as compared to the conventional distillation process. However, the fabrication cost of polycrystalline zeolite membranes is high, predominantly dictated by the production cost of the support (≈ 50-70 %) rather than the polycrystalline zeolite layer. Herein, we report the fabrication of polycrystalline MFI membranes on inexpensive coarse macroporous α-Al 2 O 3 tube supports (symmetrical supports) with an average pore size in the range of 2 ∼ 3μm for separating butane isomers. Macroporous α-Al 2 O 3 tube supports are coated with single (sheet-like MFI crystals) and dual (sheet-like MFI crystals + MFI crystals) seed layers to achieve the desired separation performances. For coating a single seed layer, MFI nanocrystals were employed as precursors for synthesizing sheet-like MFI crystals with a high aspect ratio as compared to the conventional MFI crystals. Taking advantage of the high aspect ratio of sheet-like MFI crystals, single seed layer was fabricated on coarse macroporous α-Al 2 O 3 tube support, eliminating the time-intensive steps to reduce the support pore size and reducing the problem of pore plugging. Subsequently, a dual seed layer (sheet-like MFI crystals + MFI crystals) was also created by hot dip coating the MFI crystals on the surface of a single seed layer with the aim of fabricating a more compact, continuous, and molecular sieving polycrystalline MFI membrane with enhanced separation performance for the separation butane isomers. After hydrothermal crystallization, polycrystalline MFI membrane (M-2) fabricated on a single seed layer exhibits a separation factor and n-butane permeance of 33.80 and 2.00x10 -7 mol/m 2 .Pa.s, respectively. In contrast, the polycrystalline MFI membrane (D-3) formed on a dual seed layer demonstrates a separation factor and n-butane permanence of 40.60 and 1.47x10 -7 mol/m 2 .Pa.s, respectively. Both these membranes demonstrate good stability and reproducibility. Fabrication of polycrystalline MFI membranes on inexpensive coarse macroporous tube supports is a crucial advancement in reducing fabrication costs and facilitating industrial implementation. However, substantial potential remains for further scaling up and enhancing the separation performance of current polycrystalline MFI membranes.
研究领域:
材料科学
·
化学工程
✓ 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）