JOURNAL OF CATALYSIS
·
2025
·
IF 6.5
Lumei Wang,Dezhang Ren,Junyu Lang,Kangqi Gao,Xiao Du,Yong Yang,Zhibao Huo
Although homogeneous acid catalysts have been widely utilized in the production of solketal from glycerol, a significant aspect of the biodiesel industry, challenges remain, including the high corrosiveness of the catalysts and their excessive usage. In this study, a composite material of wCo(NO 3 ) 2 /γ-Al 2 O 3 was synthesized through an adsorption–desorption approach based on wet impregnation, achieving a Co(II) loading of only 1.8 wt%, which demonstrated a solketal yield of 84 % at 80 °C, significantly outperforming the catalytic activity of Co(NO 3 ) 2 . Even when the amount of Co(NO 3 ) 2 was increased to 22-fold that of the Co(II) content in wCo(NO 3 ) 2 /γ-Al 2 O 3 , the solketal yield only reached 67 %. Through systematic physicochemical characterization and theoretical calculations, it is revealed that Co(NO 3 ) 2 can be uniformly dispersed in an amorphous state on the surface of γ-Al 2 O 3 . Furthermore, γ-Al 2 O 3 facilitates a reduction in the orbital binding energy of Co and N within Co(NO 3 ) 2 . The synergistic effects of Co(II), NO 3 − , and γ-Al 2 O 3 contribute to decreasing the rate-determining energy of the ketalization reaction, thereby promoting the dehydration reactions of glycerol and acetone. Furthermore, this strategy is equally applicable to other soluble Co, Ni, and Cu salts, demonstrating universality. This method effectively reduces the usage of metal salts in the solketal synthesis process, enhancing the acid catalytic activity of the metal salts, providing an adsorption–desorption approach based on wet impregnation for the development of low-dose, highly active, and low-corrosive acid catalytic materials.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
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
Catalysis Science & Technology
·
2017
·Vol. 7
·期 15
·3268-3274
·
IF 5.773
Yanxiu Gao,Weinan Yang,Xiaodong Wu,Shuang Liu,Duan Weng,Rui Ran
Platinum nanoparticles were synthesized by a classic polyol process in ethylene glycol. The Pt nanoparticles were loaded on H-ZSM5 and γ-Al2O3 supports by wet impregnation. The as-obtained solid was thermally treated in a two-step procedure to remove the organic residues. Due to their larger particle size than the micropore size of H-ZSM5, the impregnated Pt particles were dispersed on the external surface of the zeolite support. With similar Pt particle size distribution and Pt loading, the Pt/H-ZSM5 and Pt/γ-Al2O3 catalysts were evaluated for the oxidation of NO and soot. Despite its lower activity for NO oxidation to NO2, the Pt/H-ZSM5 exhibited a much higher activity for soot oxidation in the presence of NO + O2. This abnormal NOx-assisted soot oxidation behaviour of Pt/H-ZSM5 was explained by the promoting effect of the acid sites on the zeolite.
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
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2023
·Vol. 39
·期 6
·1084-1091
·
IF 3.1
Gao Zhuangzhuang,Li Baoju,Ou Shuxian,Li Dongsheng,Fang Qianrong,Qiu Shilun,Xue Ming
M etal-organic frameworks (MOFs) are attractive in membrane separation due to their special pore structure and suitable aperture size. The fabrication of defect-free and robust MOF membranes with excellent durability is highly demanded but remains challenging. In this work, we report a one-step active γ -alumina conversion strategy for the facile and reliable fabrication of an MIL-96 membrane. In this case, the γ -Al 2 O 3 sol was dip-coated and sintered on the α -Al 2 O 3 disc as the active aluminum source and substrate for the nucleation and growth of MOF. A continuous and well-intergrown MIL-96 membrane was generated with exceptional stability due to the strong adhesion to the substrate. The resultant MIL-96 membrane yielded a satisfactory H 2 /CO 2 permselectivity and high-temperature resistance, delivering a selectivity of 12.35 with H 2 permeance of 6.20×10 −7 mol·m −2 ·s −1 ·Pa −1 at 150 °C. Moreover, the probe membrane presented remarkable durability and recyclability under harsh hydrothermal conditions. This method paves the way for constructing highly stable and selective MOF membranes and could accelerate the development of advanced membrane separation technologies for gas purification and recycling in addressing the severe energy and environmental problems.
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
RARE METALS
·
2018
·Vol. 38
·期 1
·1-13
·
IF 1.5
Liu Qi,Wang Wen-Qiang,Yang Yue,Liu Xue-Gang,Xu Sheng-Ming
Aluminum recovery is a key issue for the overall recycling of valuable metals from spent catalysts. This paper focuses on the recovery and regeneration of alumina with high additional value from the spent hydrodesulfurization catalyst CoMo/Al 2 O 3 . The results indicate that 98.13% alumina is successfully leached from the treated spent catalysts by an alkaline leaching process under the conditions of 5 mol·L −1 sodium hydroxide, a liquid/solid ratio of 20 ml·g −1 , a temperature of 160 °C and a reaction time of 4 h. In the leaching residue, no difficult leaching compound is found and cobalt and nickel are enriched, both of which are conducive to the subsequent metal recovery step. The reaction order of aluminum leaching is 0.99. This reaction fits well with the interfacial chemical reaction model, and its apparent activation energy is calculated as 45.50 kJ·mol −1 . Subsequently, γ-Al 2 O 3 with a high specific surface area of 278.3 m 2 ·g −1 , a mean size of 2.2 μm and an average pore size of 3.10 nm is then regenerated from the lixivium, indicating its suitability for use as a catalyst carrier. The recovery and regeneration of alumina from spent catalysts can not only significantly contribute to the total recycling of such hazardous spent catalysts but also provide a new approach for the preparation of γ-Al 2 O 3 with a high specific surface area using spent catalysts as the aluminum sources.
研究领域:
化学工程
·
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2022
·
IF 4.177
Rui Wang,Zhenchao Zhao,Pan Gao,Kuizhi Chen,Zhehong Gan,Qiang Fu,Guangjin Hou
The dehydration of alcohols to value-added chemicals using alumina catalysts has been industrialized decades ago; however, despite years of fundamental research, the molecular-level understanding of the reaction process is still lacking. Herein, the dehydration reactions of ethanol on two representative aluminas, i.e., γ-Al2O3 and five-coordinated Al-rich Al2O3-nanosheet (Al2O3-NS), are comparatively investigated by a combination of solid-state NMR spectroscopy and reaction evaluations. NMR results reveal that the presence of hydroxyl groups nearby the Lewis acid sites (LASs) leads to different ethanol adsorption modes. The surface hydroxyls nearby LASs interfere with ethanol adsorption, which causes the methyl group to move away from the alumina surface and hinders the elimination of β-H, resulting in low reaction activity. In addition, the desorption property of surface hydroxyls will affect the dehydration reaction as they participate in the catalytic reaction cycles. Such effects may also explain the lower reaction activities for diethyl ether to ethylene compared with ethanol. Although both four- and five-coordinated Als are the possible active sites for ethanol dehydration, the reactivity of alcohol dehydration may also be substantially affected by the local environment of undercoordinated Als besides coordination numbers. These new insights demonstrate that the host–guest interaction regulated by the local environment of active sites plays an important role in the catalytic reaction.
研究领域:
催化化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2022
·Vol. 41
·期 11
·3684-3693
·
IF 6.318
Zhang Xi-Yue,Zhang Le,Zhou Tian-Yuan,Sun Bing-Heng,Wei Shuai,Cao Yi-Fei,Liu Ming-Yuan,Sang Peng-Fei,Wei Cong,Chen Wei,Chen Hao
High specific surface of (α/γ)-Al 2 O 3 powder is essential for its applications in adsorbents, catalysts or ceramic raw materials. However, the phase transformation from precursor to oxide powder inevitably experiences the high-temperature calcination process which coarsens or agglomerates the particles, and then loses the high dispersity and activity. In this study, a novel spray precipitation operation was employed to synthesize the nanostructured ammonium aluminum carbonate hydroxide (AACH) and boehmite (γ-AlOOH) precursors in single precipitation method just depending on pH values. The high specific surface area (250.34 m 2 ·g −1 ) and high pore volume (0.96 ml·g −1 ) of as-prepared γ-Al 2 O 3 powder were inherited from fresh sea-urchin-like AACH precursor prepared at pH = 9. The sequential hydrolysis effect accelerated the unstable AACH precipitate to evolve into nearly spherical γ-AlOOH at a lower pH = 5. The special nano-clusters of AACH effectively reduced the phase transformation temperature of γ-Al 2 O 3 . In addition, the precipitation, nucleation and growth mechanisms and phase transformation sequences from different precursors to oxide powders were further proposed. Therefore, this work shows how pH value driving spray precipitation leads to a provisional change in morphology of precursors, but also to a permanent change in dispersion state of powders. It significantly affects the catalysis properties of Al 2 O 3 powders and its performance in adsorbent or electronic ceramics. These results are crucial for advancing Al 2 O 3 -supported technologies. Graphical abstract
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Yumeng Zhao,Guoshu Gao,Peng Zhu,Haiou Liu,Yu Guo,Xiongfu Zhang
The preparation of stable metal–organic framework tubular membranes for liquid mixture separation has always been a tough problem. Herein, a flexibly prepared, continuous, and stable Al-based CAU-10 membrane with ceramic tubes as support was developed by a thin γ-Al2O3 layer induction method and employed for the first time in the separation of MeOH/MTBE azeotropic mixtures through pervaporation. The γ-Al2O3 layer introduced on the tube by the dip-coating technique not only facilitated the crystal nucleation and continuous growth of CAU-10 membranes but also reinforced the membrane stability by acting as anchoring sites between the membrane and the substrate. The as-prepared CAU-10 tubular membrane exhibited excellent separation performance for MeOH/MTBE mixtures owing to its suitable pore size and good hydrophilicity. For the separation of 14.3 wt % MeOH/MTBE azeotropic mixtures, the membrane displayed a permeation flux of 1.76 kg/(m2 h) and a high separation factor of 2041 at 50 °C, which is better than most of the membranes reported for the pervaporation separation of MeOH/MTBE mixtures. More excitedly, the CAU-10 tubular membrane continued to be tested for more than 7 days without any obvious change in pervaporation performance, demonstrating its outstanding operational and hydrothermal stability. Accordingly, the CAU-10 tubular membrane would be a promising alternative to separate the MeOH/MTBE azeotropic mixtures due to its easy preparation, high performance, and excellent 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
JOURNAL OF RARE EARTHS
·
2025
·
IF 7.2
Jie Dong,Meiqing Shen,Haoxuan Liu,Wei Li,Feng Gao
To investigate the impact of pore diameter on the thermal stability of La-doped transition aluminas, we examined three γ-Al 2 O 3 materials with distinct pore diameters, both with and without La doping. Via material characterizations including N 2 adsorption-desorption, X-ray diffraction (XRD), thermogravimetric analysis, X-ray photoelectron spectroscopy (XPS), 27 Al and 1 H nuclear magnetic resonance (NMR), we discover that in the absence of La doping, the thermal stability of Al 2 O 3 decreases significantly with decreasing pore diameter. For La-doped Al 2 O 3 , the influence of pore diameter on thermal stability is mitigated at 1100 °C but re-emerges at 1200 °C. We propose that the La species that provide structure protection are highly, or even atomically dispersed on the alumina surface. La 2 O 3 or LaAlO 3 aggregates, if even present, are not the main La moieties that provide structure protection. The highly dispersed La species occupy defective sites on Al 2 O 3 , effectively slowing down phase transformation to α-Al 2 O 3 . At 1200 °C, La diffuses into the Al 2 O 3 bulk and as such, loses its protective function.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2016
·
IF 7.354
Xuelin Zou,Zebao Rui,Shiqi Song,Hongbing Ji
Poor durability and low Pd utilization efficiency are the main drawbacks of supported Pd catalysts for low-temperature methane combustion. Here, we present a facile way to stabilize the performance of Pd/Al 2 O 3 by introducing a spinel NiAl 2 O 4 interface as a promoter at no cost to the activity. The NiAl 2 O 4 interface is formed by impregnation of alumina supports in the nickel-containing solution, followed by high-temperature calcination. A series of 0.4 wt.% Pd/ x NiO/γ-Al 2 O 3 with NiO loading varying among 0.0, 0.5, 1.0, and 9.0 wt.% is investigated. The formation of a NiAl 2 O 4 interface promotes the distribution and crystallization of PdO, suppresses PdO particles aggregation and surface OH − species accumulation during the reaction, and finally leads to the excellent performance of Pd/0.5NiO/γ-Al 2 O 3 . Pd/0.5NiO/γ-Al 2 O 3 demonstrates higher Pd utilization efficiency than the state-of-the-art Pd-based catalysts and better stability than Pd/Al 2 O 3 . Such a spinel interface promotion strategy may bring new insight into the design of highly efficient Pd-based catalysts and their potential technological applications.
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
NEW JOURNAL OF CHEMISTRY
·
2021
·Vol. 45
·期 36
·16750-16759
·
IF 3.591
Yining Zheng,Cundi Wei,Qi An,Jinsheng Yu,Shaonan Xu,Lina Li
The aluminum alloy is used as the aluminum source, together with melamine and cyanuric acid, in a water reaction system to obtain the precursor of Al2O3/g-C3N4 through self-assembly in one step, and then calcined to obtain the Al2O3/g-C3N4 composite photocatalytic material. γ-Al2O3 has a defect site that can accept g-C3N4 electrons and can bind well with g-C3N4. The addition of γ-Al2O3 changed the morphology of g-C3N4 into a damaged tubular structure with many irregular pores. Also, the specific surface area increased to about 1.2 times that of g-C3N4, and the light absorption edge was extended to 500 nm. In addition, the position of the valence band of g-C3N4 was also changed. Compared with g-C3N4, Al2O3/g-C3N4 has better photocatalytic performance, and the degradation rate of dye rhodamine B (RhB) is about 1.70 times that of g-C3N4.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Xin Song,Wenjie Pan,Fangjun Shao,Zijiang Zhao,Xiaonian Li,Zhongzhe Wei,Jianguo Wang
The development of alkyne semihydrogenation catalysts with high conversion and selectivity under mild conditions is extremely challenging. Here, the modulation of Pd by different crystalline aluminas was investigated to improve the reaction performance. XPS confirmed that different crystalline aluminas modified the electronic structure of palladium. The Pd0.5/γ-Al2O3 catalyst with a Pd loading of 0.48 wt % attained 98% conversion and 91% selectivity. Stronger interaction of the γ-Al2O3 support with the loaded Pd nanoparticles resulted in electron deflection toward the support. The electronic structure of Pd was altered by modulating the crystallographic shape of the support, resulting in metal nanoparticles containing more Pd2+. Electron-deficient Pd2+ adsorbs more strongly on an electron-rich C≡C, which in turn modulates the competitive adsorption of alkenes and alkynes. Finally, the effective semihydrogenation of phenylacetylene was realized at low temperature and pressure.
研究领域:
化学工程
·
催化
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）