APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Qiu Xu,Chungang Wang,Zongling Shang,Chao Zhang,Xinchao Wang,Qiang Liu,Lingling Dang,Yanchun Liu,Fengyu Zhao
The activation and ring opening reaction of lactone bond is of great significance in biomass utilization. Cu-based catalysts are widely used in the biomass hydrogenation processes, in which the effect of oxide promoters on Cu catalysts is one of the most attractive research topics. Herein, the transformation of lactones to diols over Cu/Al 2 O 3 and CuLa x /Al 2 O 3 catalysts was studied and the promoting role of LaO x has been discussed. The CuLa 0.25 /Al 2 O 3 catalyst showed outstanding catalytic performance with high 1,4-butanediol yield of > 90 %, and it also showed high efficiency for the hydrogenation of series of five- and six-membered lactones (γ-butyrolactone, γ-valerolactone, δ -hexalactone, etc) to diols. Based on the comprehensive analysis of the XRD, TEM, TPR, XPS, low temperature CO-DRIFT results, the crucial contribution of LaO x species in promoting the selectivity and stability of catalysts were investigated in detail. The presence of LaO x species not only results in the formation of Cu + -LaO x interfacial active sites, which facilitate the adsorption and activation of lactones, but also promotes the stability of catalyst.
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
CATALYSIS TODAY
·
2022
·
IF 6.562
Mingsheng Luo,Chenmeng Li,Qinglong Liu,Zhi Yang,Yatao Wang,Hongjuan Li
Direct hydrogenation of CO to alcohols through Fischer-Tropsch reaction process is taken great interest in recent years. In this study, a series of β-Mo 2 C/γ-Al 2 O 3 catalyst are prepared to investigate the influence of carbon and molybdenum precursor, calcination temperature, as well as the molar ratio of the carbon precursor to molybdenum precursor compounds on catalyst microstructures and the catalytic performance. The microstructure characteristics of the catalysts were examined with XRD, BET, ICP, SEM and CO-TPD. The performance test of the catalysts for syngas-to-alcohol was investigated in a fixed-bed reactor. Properly excessive amount of hexamethylenetetramine as carbon precursor calcined at a high temperature (≥700 ℃) favors the formation of high crystalline β-Mo 2 C on γ-Al 2 O 3 carrier. Catalysts with different amount of Mo were prepared to study the effect of active metal loading on microstructure and catalytic performance. The results show that the particle size of β-Mo 2 C and CO dissociation adsorption capacity, as well as the CO conversion increases with raised Mo loading. The selectivity of all higher alcohols reached the maximum when 25 % of Mo was loaded.
研究领域:
催化
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化学工程
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材料科学
✓ 已验证
DOI
高影响因子
Royal Society Open Science
·
2022
·Vol. 9
·期 9
·
IF 3.653
Haijun Cheng,Chang Yu,Hongyun Wang,Xiongmin Liu,Li Ma,Fang Lai
It has been a challenge to synthesize macrolide musk in excellent yields with high purity. KF-La/γ-Al2O3 catalyst was prepared from a highly basic mesoporous framework using a mild method. The prepared KF-La/γ-Al2O3 catalyst was employed for the synthesis of cyclopentadecanolide from methyl 15-hydroxypentadecanoate. The morphology and structure of prepared catalysts were characterized using XRD, TG-DTG, SEM, EDX, TEM, BET and CO2-TPD. The results revealed that the K3AlF6 and LaOF are produced on the surface of KF-La/γ-Al2O3, and LaO can promote the dispersion of KF on the surface of Al2O3. Catalysts pore size main distribution ranges between 10 and 30 nm, the maximum CO2 desorption temperature is 715°C when the La loading is 25%. Because F− ion has a higher electronegativity than O2− ion, the KF-promoted metal oxide (Al2O3 or/and La2O3) contained more strong basic sites, compared with that of the corresponding metal oxide. The yield of cyclopentadecanolide obtained at 0.5 g KF-25La/γ-Al2O3 catalyst and a reaction temperature of 190°C for 7 h were 58.50%, and the content after reactive distillation is 98.8%. The KF-La/γ-Al2O3 catalyst has a larger pore size and basic strength, which is more conducive to the macrolactonization of long-chain hydroxy ester.
研究领域:
有机化学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Zhijun Guo,Guoliang Zhang,Lei Wang,Ping Li,Chunshan Li
To meet the increasing demand for methyl methacrylate, a series of Fe modified Cs–P/γ-Al2O3 catalysts were developed through the impregnation method and tested for the aldol condensation of methyl propionate with formaldehyde in a fixed-bed reactor. Through various characterization studies, the physicochemical properties of the catalysts were systematically studied, especially the relationship between the number of the acid sites and catalytic activity. The number of medium acid sites was increased effectively by the addition of Fe, and the catalytic selectivity was improved consequently. Moreover, the reaction conditions were also optimized, and the life span of the optimized catalyst was evaluated. The Cs–P–0.1Fe/γ-Al2O3 showed excellent reusability during a 260 h lifetime experiment.
研究领域:
化学工程
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催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2010
·
IF 1.758
Zhiqiao He,Angliang Zhang,Shuang Song,Zhiwu Liu,Jianmeng Chen,Xinhua Xu,Weiping Liu
In an attempt to utilize ozone effectively, a series of praseodymium-modified γ-Al2O3 (Pr/Al2O3) was prepared via incipient wetness impregnation using Pr(NO3)3·6H2O as the precursor. The structure and properties of the catalysts were studied by X-ray diffraction (XRD) and the Brunauer−Emmett−Teller (BET) method. Catalytic activity was evaluated by monitoring the degradation of succinic acid (SA) in the presence of ozone. The praseodymium modification can effectively enhance the ozonation activity of γ-Al2O3 upon SA removal. Increasing the calcination temperature of Pr/Al2O3 is disadvantageous for the catalytic process, whereas increasing the load of praseodymium is helpful. After three successive cycles, the Pr/Al2O3 catalyst remained stable in the catalytic ozonation of SA. Overall, the initial degradation rate of SA, as well as the saturated adsorption capacity of SA, were found to have a linear relation to changes of the surface hydroxyl groups of the catalyst. On this basis, we conclude that the significant enhancement of SA degradation using Pr/Al2O3 as a catalyst should be because praseodymium, in the form of Pr6O11, promoted the formation of surface hydroxyl groups. Hence, the adsorption was increased, and the degradation rate of SA was enhanced.
研究领域:
环境化学
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催化科学
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水污染控制
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材料化学
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环境工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Jingru Qiu,Guo-Qing Yang,Jiachang Zuo,Xiaoying Liu,Zhipeng Lan,Weikun Chen,Zhong-Wen Liu,Youzhu Yuan
The selective oxidation of methyl glycolate (MG) to methyl glyoxylate (MGO) using molecular oxygen in a fixed-bed reactor represents a greener and more efficient alternative to the traditional batch processing for producing this important fine chemical and intermediate. Despite its potential, detailed understanding of this catalytic reaction is still limited. In our study, VO x / γ -Al 2 O 3 catalysts were identified as effective for the reaction, but their performance strongly depended on the structure of VO x species. The optimal catalyst with nearly monolayer dispersed VO x achieved a high MG conversion of 91% and an MGO selectivity of 71%, alongside maintaining stability for 300 h without noticeable deactivation. At a low V loading of 0.6%, isolated VO x species were formed, exhibiting the highest turnover frequency (TOF) but the lowest MGO selectivity. Increasing the V loading to 3.9% resulted in a blend of less polymeric and isolated VO x species, which decreased the TOF but enhanced MGO selectivity to 59%. With the V loading ranging from 5% to 6.2%, monolayer dispersed VO x became dominant, yielding a lower TOF and the highest MGO selectivity. A further increase in V loading caused the emergence of crystalline V 2 O 5 , which seemed to act as a bystander. Moreover, the redox cycles of V 4+ and V 5+ over the VO x / γ -Al 2 O 3 catalyst played an important role in the selective oxidation of MG to MGO, while the overoxidation of MG to CO 2 might take place through the V 3+ /V 4+ redox pairs, the extent of which was determined by the structure of VO x species. These insights are crucial for developing high-performance VO x -based catalysts for the production of MGO through the selective oxidation of MG.
研究领域:
催化化学
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Nan Shi,Hengxi Zhu,Jiamin Qi,Bin Li,Jin Zhang
Carbonyl sulfur (COS) was difficult to be removed by conventional desulfurization technologies because of its stable chemical properties. Mesoporous γ-Al 2 O 3 (MA) showed excellent potential for hydrolysis of COS, but the catalyst life was greatly shortened with the progress of the reaction. Therefore, improving the catalyst life is the key to MA which can apply to hydrolysis of COS. In this study, P123 modified mesoporous γ-Al 2 O 3 (P-MA) catalyst was prepared by sol–gel method, and it was regulated by template agent and acidity regulator. These preparation conditions of P-MA were optimized to improve the hydrolysis efficiency of COS. The effects of temperature, space velocity, relative humidity and oxygen concentration for the hydrolysis efficiency of COS were studied. The results show that the optimized P-MA catalyst is suitable for COS low-temperature hydrolysis reaction, and it can maintain 99 % for 10 h under the tough reaction conditions. The only crystal of P-MA was γ-Al 2 O 3 with large specific surface area and uniform distribution pore, which are beneficial to the COS hydrolysis. In addition, the hydrolysis efficiency of COS can also remain 97 % for 10 h in the O 2 and CO 2 atmosphere, indicating that the P-MA catalyst has a specific anti-poisoning ability. The kinetics and reaction mechanism of COS catalytic hydrolysis were studied, which showed that the adsorption of H 2 S was the key to hindering the continuous reaction. The P-MA can effectively inhibit the adsorption of H 2 S, which greatly improved COS hydrolysis life of P-MA. This study provided a theoretical basis for the application of Al 2 O 3 catalyst in the COS hydrolysis.
研究领域:
化学工程
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Zhiquan Yu,Yan Li,Yunlong Yao,Yao Wang,Ying-Ya Liu,Zhichao Sun,Chuan Shi,Wei Wang,Anjie Wang
A bifunctional Ni 3 P/γ-Al 2 O 3 catalyst with both metal site and Lewis acid site was prepared by an electroless plating method, and applied in hydrogenative ring-rearrangement of furfural to cyclopentanone. The obtained catalyst was characterized by XRD, XPS, XAS, N 2 adsorption-desorption, ICP, TEM, CO chemisorption, NH 3 -TPD and Py-FTIR. The ultrafine Ni 3 P nanoparticles (∼3.8 nm) were highly dispersed in the catalyst. The exclusive Lewis acidity of Ni 3 P/γ-Al 2 O 3 was beneficial for the aqueous-phase hydrogenative ring-rearrangement. The effects of DP time, reaction parameters (temperature, H 2 pressure, solvent composition, and reaction time) on the catalytic performance were investigated. The yield of cyclopentanone was 74.6% at furfural conversion of 99.9% at 180 °C in 1 h over Ni 3 P/γ-Al 2 O 3 catalyst using pure water as the solvent. Moreover, the kinetics of hydrogenative ring-rearrangement of furfural catalyzed by Ni 3 P/γ-Al 2 O 3 was investigated.
研究领域:
催化化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Di Zhang,Lijun Xue,Yongqiang Xu,Lijuan Song,Xinmei Liu
Mesoporous γ-Al 2 O 3 supports with different pore structures were prepared by the cation-anion double hydrolysis method. Based on these samples, MoO 3 /γ-Al 2 O 3 catalysts were made via impregnation. The adsorptions of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and collidine over the supports and catalysts were studied by FT-IR. The supports or catalysts with larger pores can adsorb more 4,6-DMDBT. The methyl groups on adsorbate molecules are very close to the sulfur atom , resulting in apparent steric hindrance . Increasing the pore size can promote the interaction between the adsorbates and supports or catalysts, enhancing the C C bond and weakening the C S bond of 4,6-DMDBT. 4,6-DMDBT molecules were coordinated with the unsaturated Mo atoms over the catalysts to form π-complexation adsorption. There was much difference between thiophene and 4,6-DMDBT adsorption. The adsorption of collidine over the catalysts also illustrated that there existed steric hindrance. Significantly, the catalyst with hierarchical mesopores was beneficial for the adsorbates with larger molecular dynamics diameter. Compared with the pore size, the specific surface area was not the key factor to affect the adsorptions of 4,6-DMDBT and collidine. The hydrodesulfurization reaction of 4,6-DMDBT illustrated that the catalysts with larger pore size or hierarchical pore structure presented higher desulfurization efficiency (above than 80%).
研究领域:
催化化学
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能源化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Fuhang Mai,Zhe Wen,Yunfei Bai,Zewei Ma,Kai Cui,Kai Wu,Fei Yan,Hong Chen,Yongdan Li
A WO3/γ-Al2O3 catalyst prepared by an incipient-wetness impregnation method is employed in the selective conversion of enzymatic hydrolysis lignin (EHL) into various alkylphenols in supercritical ethanol. In the reaction, EHL is completely dissolved and converted into aliphatic and aromatic compounds with a total yield of 363.4 mg/g lignin at 320 °C for 8 h. The yield of aromatic compounds is 315.8 mg/g lignin, accounting for 86.9% of the total yield of the products, and the overall selectivity of alkylphenols reaches 67.5%. Compared to WO3 and H2WO4, the WO3/γ-Al2O3 shows a higher activity for the conversion of EHL in supercritical ethanol. Besides, ethanol is found to be the most effective solvent for the depolymerization of EHL with the WO3/γ-Al2O3 catalyst. The WO3/γ-Al2O3 keeps the high catalytic activity in three reuses.
研究领域:
生物化学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
SOLID STATE IONICS
·
2019
·
IF 2.886
Fan Deng,Yongmin Wu,Weiping Tang,Shufeng Song,Zhaoyin Wen,Masashi Kotobuki,Li Lu,Jianyao Yao,Ning Hu,Janina Molenda
The use of garnet-type conductors as electrolytes for safe lithium solid-state batteries is impeded by the lack of critical processing strategy to stabilize and densify the cubic lithium garnets. The synthesis and processing of dense cubic lithium garnets are typically depending on solid state reaction as a result of unintentional Al contamination from the alumina crucibles at temperatures up to 1230 °C. High Al concentration is also believed to induce the sluggish migration of lithium ions . Here, we demonstrate an ultrathin, conformal γ-Al 2 O 3 surface coating on garnet solids by a hybrid microemulsion solid-state method for accomplishing rational and controllable synthesis and processing of dense cubic garnets with low Al concentration. The γ-Al 2 O 3 coating demonstrates fast-ion conducting Al-doped Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 phase with low Al concentration (~0.17 mol per formula unit), low tetragonal-to-cubic phase transformation temperature of 500 °C, and total conductivity of ~4.4 × 10 − 4 S cm − 1 . Specifically, the desired microstructures of the sintered pellets with uniform grains are revealed. As a proof-of-concept, we demonstrate that the nanoscale γ-Al 2 O 3 modification garnet conductor Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 is available to suppress lithium dendrites in symmetric Li/γ-Al 2 O 3 coating Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 /Li cells during lithium plating/stripping at room temperature, with current densities of 0.026 to 0.5 mA cm − 2 . The Li/γ-Al 2 O 3 coating Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 /LiNi 0.5 Co 0.2 Mn 0.3 O 2 cell delivered a high initial discharge capacity of ~164.2 mAh g − 1 , more importantly, an outstanding cycling performance with a capacity retention of 90.16% after 30 cycles at 0.1C and room temperature. This new synthesis route and the utilization of nanoscale γ-Al 2 O 3 surface modification could open up new avenue to lithium garnet conductors with reliable synthesis for all-solid-state lithium batteries application.
研究领域:
材料科学
·
电化学
·
固态离子学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 46
·期 7
·9289-9296
·
IF 3.83
Mohamed S. Selim,Ping Jing Mo,Yu Ping Zhang,Zhifeng Hao,Hongli Wen
Ceramic one-dimensional particles are fascinating nanomaterials for sustainable future industries. Nanorods of γ-Al 2 O 3 with single crystallinity and 10 nm diameter regime were newly developed through solvothermal procedure between AlCl 3 ·6H 2 O, NaOH, and sodium dodecylbenzene sulfonate at 200 °C for 24 h. Controlling the pH values, reaction time, temperature, and effect of surfactant during the solvothermal reaction was studied to control the morphology and structure of nanorods. The solvothermal procedure for preparing γ-AlOOH nanorods followed lamellar growth, assembly, and ripening routes. The γ-AlOOH nanorods were converted to γ-Al 2 O 3 through calcination reaction at 500 °C for 3 h. The produced γ-Al 2 O 3 nanorods were 10 nm average width, 100–200 nm average length, and exposed with [101] orientation and a linear structure. FTIR, HRTEM , FESEM, XRD , and X-ray photoelectron spectroscopy methods were used for characterizing the prepared nanomaterials . New features and applied fields are predictable for the designed γ-AlOOH and γ-Al 2 O 3 nanorods.
研究领域:
无机化学
·
纳米材料科学
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溶剂热合成
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陶瓷纳米材料
·
材料化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）