ACS Catalysis
·
2016
·
IF 9.307
Gang Liu,Zhi-Jian Zhao,Tengfang Wu,Liang Zeng,Jinlong Gong
Supported VOx catalysts are promising for use in propane dehydrogenation (PDH) because of the relatively superior activity and stable performance upon regeneration. However, the nature of the active sites and reaction mechanism during PDH over VOx-based catalysts remains elusive. We examined active species by attaining various fractions of V5+, V4+, and V3+ ions by adjusting the surface vanadium density on an alumina support. The results reveal a close relationship between TOF and the fraction of V3+ ion, indicating that V3+ was more active for PDH. In situ diffuse reflectance infrared Fourier transform spectroscopy showed the same strong adsorbed species during both propane dehydrogenation and propylene hydrogenation. The results indicated that such an intermediate may correspond to V species containing a C═C bond, i.e., V–C3H5, and a reaction mechanism was proposed accordingly.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
·
2022
·
IF 6.796
Xiao Chen,Yong Wang,Jianyu Li,Zhongheng Hu,Ying Zhou,Huayan Liu,Hanfeng Lu
The preparation of highly active supported noble metal catalysts with a low noble metal loading has always been the ultimate goal of researchers working on catalysis. Hydrothermally treated Pt/Al 2 O 3 (Pt/Al 2 O 3 -H) exhibits better catalytic activity than that (Pt/Al 2 O 3 -C) treated via the conventional calcination approach. At the high space velocity of 100,000 mL/(g∙hr), the temperature that correspond to 50% toluene conversion ( T 50 ) of Pt/Al 2 O 3 -H is 115°C lower than that of Pt/Al 2 O 3 -C, and the turnover frequency (TOF) value can reach 0.0756 sec −1 . The mechanism by which the hydrothermal approach enhances Pt/Al 2 O 3 activity has been investigated. The structure associated with the high catalytic activity of Pt nanoparticles (NPs) can be retained via hydrothermal treatment. Furthermore, the support is transformed to AlO(OH) with numerous surface hydroxyl groups, which in turn can facilitate the adsorption of toluene. And the synergistic effects of Pt NPs and AlO(OH) increases the contents of Pt in oxidation state and active oxygen, which are beneficial for toluene oxidation.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2024
·
IF 2.3
Chengpeng Zhang,Hongjing Liu,Hanyu Qiu,Wei Zhao,Xu Zhao,Xiaochun Jing,Hui Yao
Nano-organic hybrid materials (Al2O3-NOHMs) were synthesized with nano-alumina as the core, γ-(2,3-epoxypropyl) propyl trimethoxysiane (KH560) as the corona, and three of polyetheramine M2070, D2000, M1000 as the canopy, respectively. Al2O3-NOHMs were used as fillers to prepare MMMs with Pebax as substrate to improve the CO2 separation performance. The Al2O3-NOHMs were characterized by TEM and rheological properties. The results showed that the synthesized Al2O3-NOHMs were liquid-like and had a core-shell structure, which can effectively reduce Al2O3 agglomeration in the membrane. FT-IR analysis of MMMs showed that Al2O3-NOHMs and Pebax were physically blended, TGA indicated that Al2O3-NOHMs do not affect the thermal stability of the membrane, and XRD indicated that the addition of Al2O3-NOHMs destroyed the interchain hydrogen bond of Pebax and reduced the crystallinity of MMMs. The gas permeability of the membrane was tested under ideal gas conditions, compared with pure membrane, the CO2 permeability of Al2O3-NOHM(M2070)/Pebax MMMs and Al2O3-NOHM(D2000)/Pebax MMMs reached 137.15 Barrer (24.68%) and 147.52 Barrer (34.11%), and the selectivity of CO2/N2 reached 77.82 (58.84%) and 72.31 (47.59%) at 30°C and 0.3 MPa, respectively, surpassing 2008 Robeson upper bound.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Zhe Zhang,Jianan Zhang,Shuai Chen,Yanan Liu,Yufei He,Dianqing Li
Hydrogen spillover phenomenon can significantly impact the activity in hydrogenation reaction, but the spillover is limited in a very short range on non-reducible Al 2 O 3 , a most widely used industrial support. Herein, Al 2 O 3 doped with different lanthanides (ln) was prepared by co-precipitation, which was then used to produce Pd/ln-Al 2 O 3 catalysts. These catalysts display much higher hydrogenation activity towards alkylated anthraquinone than undoped Pd/Al 2 O 3 catalyst and those modified by non-lanthanide elements. After the introduction of lanthanides, the reaction order of H 2 decreases from 1 to 0. Further characterization and DFT calculation show that H 2 storage ability is increased for ln-doped catalysts due to the low activation energy of H transfer and low adsorption energy of H on O(-ln) sites. In addition, a reasonable relationship between reducibility of ln 3+ in catalysts and the catalytic performance is found.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 36
·期 5
·940-945
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IF 1.071
Shi Chengying,Yang Jiayu,Liu Yang,Wang Yanmiao,Xu Wenge,Xu Yiquan,Hu Wei,Liu Baijun
The surface-modified Al 2 O 3 particles were introduced into polyethylene(PE) to enhance the thermal conductivity, and PE/Al 2 O 3 cross-linked networks with improved thermal and mechanical properties were prepared through electron beam(EB) irradiation technology. The incorporation of reactive irradiation sensitizer was useful in fabricating a high degree of cross-linking(DC) PE networks under a low irradiation dose. In the PE sample containing 2% sensitizer, DC ca. 67.1% could be obtained under 60 kGy(1 kGy=1000 J/kg). EB-irradiation greatly improved the tensile stress of PE-based samples, and the tensile stresses of the samples with 0.2%—5% TMPTA(trimethylolpropane triacrylate) under 60 kGy were 24.61—27.77 MPa. All the EB-irradiated samples had higher Vicat softening temperatures than the samples without irradiation. After treatment at 120 kGy, the Vicat softening temperatures of PE-Al 2 O 3 -44/ TMPTA-2 increased from 127 °C to 130.4 °C. SEM images revealed that PE-Al 2 O 3 -50 samples with increased amount of Al 2 O 3 particles showed a conduction “pathway,” and thermal conductivity reached 0.67 W/(m·K). Thus, high-performance pipes were successfully extruded, which could satisfy the static hydraulic blasting test and exhibit improved thermal conduction capability.
研究领域:
材料科学
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热传导工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2022
·
IF 6.437
Koïta Djakaria,Ziyue Tang,Jingai Shao,Xu Chen,Haoyu Xiao,Joseph Smith,Haiping Yang,Hanping Chen
Furfural is one of the top valuable building block chemicals, the selective production of furfural from biomass has attracted increasing concerns in recent years. In this work, a novel method for the selective production of furfural through cellulose catalytic pyrolysis with WO 3 /γ-Al 2 O 3 was reported, and the synergistic effect between γ-Al 2 O 3 and WO 3 was explored. Compared with cellulose pyrolysis alone, the addition of γ-Al 2 O 3 improved the selectivity of furans and greatly inhibited the formation of sugars; while, WO 3 addition promoted the formation of levoglucosenone . When (20–40%) WO 3 /γ-Al 2 O 3 were added, the amount of sugars was further reduced, and the yields of furans (furfural and 2-methylfuran, in particular) were further increased at the same time. Under the optimum conditions (temperature = 600 °C, residence time = 15 s, and catalyst to cellulose mass ratio of 4), 30%WO 3 /γ-Al 2 O 3 showed the best performance, and the selectivity and yield of furfural were improved by nearly 100% and 300%, respectively, as compared with cellulose pyrolysis alone. In addition, compared with γ-Al 2 O 3 , the addition of 30%WO 3 /γ-Al 2 O 3 further increased the yield of furfural and 2-methylfuran to about 50% and 200%, respectively. The high selectivity and yields of furans with WO 3 /γ-Al 2 O 3 addition might be due to that WO 3 crystals in the composite promote the formation of levoglucosenone, which is further converted to additional furans through the Lewis acid sites of γ-Al 2 O 3 . The study may provide some meaningful advices for improving the production of furfural from green catalytic pyrolysis of cellulose.
研究领域:
化学工程
·
可再生能源
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Mengwen Zhang,Fanyu Meng,Binyang Jiang,Jinsheng Li,Lei Fan,Shoulei Yang
To further enhance the performance of Al 2 O 3 -Ti(C,N) composites, this study employed novel sinter forging and dynamic sinter forging techniques, comparing them with conventional hot pressing and oscillatory pressure sintering. The results revealed that the composites produced by all four processes exhibited high density and no phase transition or formation of new phases. However, the composites prepared by sinter forging and dynamic sinter forging exhibited significantly improved strength and hardness. The hardness of the composites produced by sinter forging increased to 23.39 GPa, while the strength reached 1142 MPa, representing a 61 % improvement compared to those sintered by hot pressing. This improvement can be attributed to the significant plastic deformation induced by the sinter-forging process, which results in a higher dislocation density at the grain boundaries and within certain grains, enhanced coordinated deformation between grains, and stronger grain boundary bonding. Furthermore, the average grain size was smaller. Therefore, sinter forging and dynamic sinter forging offer substantial advantages in the preparation of advanced ceramics.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Yu Gu,Haijun Liu,Miaomiao Yang,Zhipeng Ma,Lianming Zhao,Wei Xing,Pingping Wu,Xinmei Liu,Svetlana Mintova,Peng Bai,Zifeng Yan
The relatively low cost and mild toxicity of vanadium makes it an alternative to commercially applied Pt and Cr based catalysts in propane dehydrogenation (PDH). Conventional VO x /Al 2 O 3 catalyst shows high initial activity, but deactivates fast due to severe coke formation, which requires frequent regeneration by coke combustion and causes massive CO 2 emissions. In this context, we report on the phosphine (PH 3 ) surface modification of VO x /Al 2 O 3 catalyst leading to substantial improvement of its stability. The phosphorus considerably modifies the properties of the VO x /Al 2 O 3 catalyst: (i) tunes surface acidity, (ii) separates polymerized vanadium oxide species and (iii) weakens interaction between vanadium species with alumina support. Synergy among all these factors facilitates desorption of produced propylene and inhibit the oligomerization of coke precursors, which contributed to the enhancement of the catalyst stability during propane dehydrogenation.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2019
·
IF 4.914
Ziyan Zhao,Dmitry E. Doronkin,Yinghao Ye,Jan-Dierk Grunwaldt,Zeai Huang,Ying Zhou
Light illumination has been widely used to promote activity and selectivity of traditional thermal catalysts. Nevertheless, the role of light irradiation during catalytic reactions is not well understood. In this work, Pt/Al 2 O 3 prepared by wet impregnation was used for photothermal CO 2 hydrogenation, and it showed a photothermal effect. Hence, operando diffuse reflectance infrared Fourier-transform spectroscopy and density functional theory calculations were conducted on Pt/Al 2 O 3 to gain insights into the reaction mechanism. The results indicated that CO desorption from Pt sites including step sites (Pt step ) or/and terrace site (Pt terrace ) is an important step during CO 2 hydrogenation to free the active Pt sites. Notably, visible light illumination and temperature affected the CO desorption in different ways. The calculated adsorption energy of CO on Pt step and Pt terrace sites was −1.24 and −1.43 eV, respectively. Hence, CO is more strongly bound to the Pt step sites. During heating in the dark, CO preferentially desorbs from the Pt terrace site. However, the additional light irradiation facilitates transfer of CO from the Pt step to Pt terrace sites and its subsequent desorption from the Pt terrace sites, thus promoting the CO 2 hydrogenation.
研究领域:
催化化学
·
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2025
·
IF 13.1
Zhitong Zhou,Weixiang Guan,Xiaoli Pan,Aiqin Wang,Tao Zhang
One-pot amination coupling of vicinal diols toward the synthesis of pyrazines provides an efficient and economically viable route to access N-heterocycles from biomass, yet the current methodology relies on a fragile homogeneous catalyst system, which limits the sustainability of the chemistry. In this work, we developed a highly efficient heterogeneous catalyst 0.8Pt/13CeO2/Al2O3 which afforded diverse substituted pyrazines from readily available vicinal diols and ammonia with a yield up to 94% under mild reaction conditions and could be reused at least 6 times without obvious activity decay. Compared to the Pt/Al2O3 catalyst, the 0.8Pt/13CeO2/Al2O3 catalyst exhibited a 30-fold faster conversion rate of diols and an increased pyrazine selectivity from 48% to 79%. Characterizations revealed that doped CeO2 improved the dispersion of Pt, increased the electron density on the Pt sites, optimized the acid/basic property of the catalyst, and enhanced the adsorption strength and dehydrogenation ability of diols. All these features contributed to the increased activity and selectivity.
研究领域:
化学工程
·
催化化学
·
生物质利用
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2020
·
IF 7.888
Chenyuan Guo,Shuguang Shen,Meina Li,Ying Wang,Jing Li,Yuanquan Xing,Cui Wang,Huajie Pan
A rapid and efficient synthesis strategy of MgAl-LDH was proposed. MgAl-LDH with high specific surface area was synthesized in situ by using η -Al 2 O 3 as carrier, and the synthesis time was greatly shortened by both increasing temperature and introducing ethanol as co-solvent. Besides, the growth process of MgAl-LDH on the surface of η -Al 2 O 3 is also revealed. Under optimized conditions, the specific surface area of the MgAl-LDH is as high as 172.4 m 2 /g, the crystalline size is as small as 12.82 nm, and the basicity can reach 1.795 mmol/g. The urea wastewater was degraded from 8000 mg/L to 6.85 mg/L over the catalyst synthesized by the rapid method, and the catalyst still maintains high activity after four uses. Also, it was found that there is a good linear relationship between the urea removal rate and the basicity of MgAl-LDH.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Chaozhong Wu,Lingjiao Zhan,Haotian Liu,Juan Wang,Wensheng Liu,Shuwei Yao,Yunzhu Ma
Understanding the mechanism of the oriented growth in multi-component alumina-based fibers and inhibiting its progression is crucial for enhancing their thermal stability. In this study, a novel diphasic fiber composed of lamellar α-Al 2 O 3 and mosaic-like mullite grains was prepared. We discussed the oriented growth behavior of lamellar α-Al 2 O 3 grains and the diffusion phenomenon of the Al element in SiO 2 substrate under the combined addition of iron sol and La 2 O 3 , proposing a new mechanism for oriented growth in diphasic fibers. The diffusion of the Si element to the tips of alumina grains contributed to a significant increase in the mobility of non-basal planes, resulting in (0001) surface growth of α-Al 2 O 3 grains. Furthermore, the La segregation at grain boundaries significantly impeded the oriented growth of α-Al 2 O 3 grains, which was critical for improving the thermal stability of multiphase alumina-based fibers.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
DOI
高影响因子
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