BIOMASS & BIOENERGY
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2017
·
IF 3.219
Haian Xia,Hong Hu,Siquan Xu,Kehao Xiao,Songlin Zuo
A series of Fe/β zeolite catalysts with various Fe/Al ratios were prepared by liquid ion-exchanged method and were characterized by N 2 adsorption, XRD , UV–Vis DRS, EPR , NH 3 -TPD, and FTIR of pyridine adsorption techniques. The catalysts were used to catalyze the transformation of glucose into 5-hydorxymethyfural (HMF) in a biphasic reaction system under mild reaction conditions. The Fe/β catalysts with Lewis acidic Fe sites is able to effectively improve the HMF yield compared to H-β zeolite under identical reaction conditions, which is ascribed to the enhanced isomerization activity of glucose-to-fructose by Lewis acidic Fe species. Moreover, the Fe/Al ratio had a remarkable impact on the conversion of glucose and the yield of HMF, indicating that the synergetic effect of Lewis and Brønsted acid sites is critical to achieving high HMF yield. Under optimal reaction conditions, Fe/β-0.06 catalyst afforded 61% HMF yield at glucose conversion of 95% after the reaction of 90 min at 120 °C, which is one of the most effective catalysts for the conversion of glucose into HMF in a biphasic medium up to now. Furthermore, extra-framework isolated Fe species bound to the framework Al sites, are most likely the active sites for the isomerization of glucose-to-fructose in the conversion of glucose. The catalysts were very stable and could be reused at least five runs without significant loss in the catalytic activity .
研究领域:
催化化学
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生物质转化
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材料科学
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产品关联
DOI
高影响因子
Reaction Chemistry & Engineering
·
2020
·Vol. 5
·期 9
·1833-1844
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IF 3.441
Guochao Yang,Lingtao Wang,Haoxi Jiang
Upgrading bio-ethanol into high value chemicals is an important issue in biomass conversion, and conversion of ethanol into butadiene is one of the most feasible methods. Here Zr-incorporating mesoporous SBA-15 (Zr–SBA-15) materials with different Si/Zr ratios were successfully synthesized by a one-pot method and were employed as catalysts for the conversion of the ethanol (EtOH)–acetaldehyde (AcH) mixture to butadiene. The textural structure and acidity of Zr–SBA-15 were investigated by using XRD, N2 adsorption, TEM, FT-IR, UV-vis, XPS, NH3-TPD and Py-IR, and the results of these characterizations indicated the mesoporosity of Zr–SBA-15 and confirmed the incorporation of Zr into the framework. Zr–O–Si bonds were formed by the incorporation and exhibited Lewis acidity predominantly. The influence of the Si/Zr ratio and reaction conditions (temperature, EtOH/AcH ratio and WHSV) showed that a suitable Si/Zr ratio was needed to balance the butadiene selectivity, by-product selectivity and total conversion. Amongst the prepared catalysts, Zr–SBA-15-20 achieved the best butadiene selectivity of 74.0% at a relatively low temperature (275 °C). The good catalytic performance could be attributed to the homogeneous dispersion of Zr species and Zr–O–Si bond generated by Zr incorporation. Furthermore, EtOH-TPD and AcH-TPD experiments proved the essential role of acetaldehyde addition and the well-accepted reaction pathway.
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
APPLIED CATALYSIS A-GENERAL
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2021
·
IF 5.706
Juan Ye,Chenyu Chen,Ying Zheng,Dan Zhou,Yunzhen Liu,Denglong Chen,Liufang Ni,Gang Xu,Fanan Wang
The selective one-pot synthesis of lactic acid (LA) from cellulose, and further the raw biomass, on heterogeneous catalysts is the key point for the development of biorefinery technology. Herein, we reported an yttrium (Y) modified siliceous Beta zeolites catalyst via two-step post-synthesis for highly efficient conversion of cellulose to LA. Under condition of 220 °C and 2 MPa N 2 , the cellulose could be transformed to LA with a yield of 49.2 % within 30 min, and the substrate can be extended to various raw biomass. It was demonstrated that the dealumination and modification of Y can efficiently modulate the acidity on the surface of zeolite. The dehydration products HMF and other derivatives were suppressed, and the yield of LA was correlated in line with the acid amount, which were attributed to the increased Lewis acidity originated by Y incorporation. These results contribute to the development of the green and efficient synthesis of bio-chemicals.
研究领域:
生物化学
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催化化学
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可再生资源
✓ 已验证
DOI
高影响因子
Catalysts
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2024
·Vol. 14
·期 4
·276
·
IF 3.8
Ting Bai,Xiaohui Li,Liang Ding,Jin Wang,Yong-Shan Xiao,Bin Cao
A series of Zn-modified HBeta (Zn/HBeta) catalysts were prepared via the wetness impregnation method with different zinc precursors such as ZnSO4·7H2O, ZnCl2, C4H6O4Zn·2H2O and Zn(NO3)2·6H2O, and their catalytic performance in the conversion of ethanol to propylene reaction was evaluated. Results indicate that the amount and strength distribution of the acid sites of the Zn/HBeta catalysts were easily tuned by employing different types of zinc precursors. More importantly, when the zinc species were introduced to the HBeta, the propylene yield was significantly enhanced, whereas the yields of ethylene and C2–C4alkanes were remarkably suppressed. For the catalyst prepared by using the ZnCl2precursor, a higher propylene yield of up to 43.4% for Zn/HBeta-C was achieved as a result of the moderate amount and strength distribution of acid sites. The average coking rate of the used Zn/HBeta catalysts strongly depended on the amount of total acid sites, especially the strong acid sites, i.e., the higher the amount of total acid sites of the catalyst, the greater the average coking rate. For the catalyst prepared by using the ZnSO4·7H2O precursor, Zn/HBeta-S exhibited a better stability even after depositing more coke, which was due to the higher amount of strong acid sites.
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
CATALYSIS COMMUNICATIONS
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2020
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IF 3.612
Shanqing Yu,Jiasong Yan,Wei Lin,Jiexiao Zhang,Jun Long
Zirconium-modified Y zeolites (ZrUSY) were prepared by impregnation of the zeolite with anhydrous-ethanol and aqueous ion exchange methods. The ZrUSY samples were characterized by powder X-ray diffraction, nitrogen physisorption, and Fourier transform infrared spectroscopy. The results indicated that ZrUSY prepared by the impregnation with anhydrous-ethanol method showed higher crystallinity, specific surface area and hydrothermal stability. The incorporation of Zr into other Y zeolites leads to an increase of the Brønsted acid site concentration and a decrease of the Lewis acid site concentration compared to the ultra-stable Y zeolite (USY). The ZrUSY was much more favorable towards heavy oil FCC conversion with decreasing coke yield and improving olefins selectivity.
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
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 47
·22672-22685
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IF 3.925
Jing Wang,Mei Zhang,Feng Li,Huan Wang,Yanguang Chen,Hua Song
To deeply understand the role of P in hydrodeoxygenation (HDO), SiO2-supported Ni and Ni–P catalysts with different P/Ni ratios (x) were prepared. The as-prepared samples were characterized by various characterization methods. The HDO activity and product distribution over the Ni/SiO2 and N–P/SiO2-x were compared and the effects of x on the structure, acidity, formation mechanism of active phases and HDO performance were studied taking m-cresol HDO as a model reaction. The results showed that the introduction of P promotes the formation of smaller active sites and contributes to the creation of weak and medium strength acid sites through the formation of P–OH groups and Niδ+ in Ni2P. HDO over the Ni/SiO2 catalyst occurs mainly via the hydrogenation (HYD) route with 3-methyl-cyclohexanol (3-MCHnol) as the main product. However, for Ni–P/SiO2-x catalysts, methyl-cyclohexane (MCH) selectivity increases first and then decreases with the increase of x, reaching a maximum of 95% at x = 1. The acidity generated by the introduction of P contributes to increased MCH selectivity, while the dehydration of 3-MCHnol to MCH occurs mainly on acid sites. However, the excessively high P content (x ≥ 2.0) leads to a significant increase of MB (toluene) selectivity, which is associated with the increase in Ni(I) sites. About 100% m-cresol conversion was achieved with Ni–P/SiO2-1.0 when the m-cresol (g)/catalyst (g) ratio was 3, with MCH (99.4%) as the major product, showing great promise for deep HDO catalysis.
研究领域:
催化化学
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能源化学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
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2016
·Vol. 6
·期 12
·4260-4270
·
IF 5.287
He Huang,Chuanhui Zhang,Lei Wang,Genqin Li,Liang Song,Guangci Li,Sifu Tang,Xuebing Li
A series of HZSM-5 supported MnOx catalysts with different manganese contents were prepared by an incipient impregnation method and tested for the catalytic oxidation of toluene. The catalytic results indicate that 10% MnOx/HZSM-5 exhibits the optimum catalytic activity, excellent catalytic durability in dry conditions and high regeneration capability in humid conditions. The dispersion of MnOx species on the HZSM-5 surface significantly reduces coke formation and simultaneously efficiently accelerates the oxidative decomposition of coke deposition during toluene catalytic oxidation. An obvious cooperative action is present on the MnOx/HZSM-5 catalysts for the catalytic oxidation of toluene, which is originally attributed to the excellent toluene adsorption capacity and trapping ability of HZSM-5 as well as the superior redox ability of the MnOx species. The correlation between characterizations and the catalytic results reveals that the mesoporous structure and low-temperature reducibility of MnOx are key factors responsible for the catalytic performance of toluene oxidation. Moreover, the Brønsted acid sites of the HZSM-5 zeolite, as active promoters, play a significant role in the catalytic oxidation of toluene through a comparative analysis with SiO2 and Al2O3 supported MnOx catalysts. The existence of a cooperative action between the redox ability of the MnOx species and the acidic properties of the HZSM-5 zeolite in the MnOx/HZSM-5 catalysts results in a high catalytic activity for the reaction.
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
DOI
高影响因子
CATALYSIS TODAY
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2015
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IF 3.893
Jing Xing,Liang Song,Cong Zhang,Mingdong Zhou,Li Yue,Xuebing Li
Upgrading of lignin derived bio-oil is a very promising way to relieve humankind's dependence on traditional fossil fuels. Eugenol, a model compound for lignin monomers with a methoxyl group and a hydroxyl group, was hydrodeoxygenated in aqueous phase with Pd/C as hydrogenation catalyst and ZSM-5 zeolite as hydrolysis and dehydration catalysts. The bulky lignin monomers had difficulty in accessing the acid sites of the micropores of ZSM-5 zeolite, thus we introduced mesopores via alkaline treatment under various conditions. Alkali-treated ZSM-5 zeolites showed higher conversion and hydrocarbon selectivity compared to the parent ZSM-5 zeolite. When ZSM-5 zeolite was treated at 338 K, the conversion and the hydrocarbon selectivity increased by 21% and 24%, respectively. In addition, much more weak acid sites of ZSM-5 zeolites after alkaline treatment also promoted the hydrolysis and dehydration process.
研究领域:
化学工程
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能源科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
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2015
·
IF 1.964
Xin Zhao,Lei Huang,Hongrui Li,Hang Hu,Jin Han,Liyi Shi,Dengsong Zhang
Different transition metals were used to modify V 2 O 5 -based catalysts (M-V, M = Cu, Fe, Mn, Co) on TiO 2 via impregnation, for the selective reduction of NO with NH 3 . The introduced metals induced high dispersion in the vanadium species and the formation of vanadates on the TiO 2 support, and increased the amount of surface acid sites and the strength of these acids. The strong acid sites might be responsible for the high N 2 selectivity at higher temperatures. Among these catalysts, Cu-V/TiO 2 showed the highest activity and N 2 selectivity at 225–375 °C. The results of X-ray photoelectron spectroscopy, NH 3 -temperature-programmed desorption, and in-situ diffuse reflectance infrared Fourier transform spectroscopy suggested that the improved performance was probably due to more active surface oxygen species and increased strong surface acid sites. The outstanding activity, stability, and SO 2 /H 2 O durability of Cu-V/TiO 2 make it a candidate to be a NO x removal catalyst for stationary flue gas.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Huansheng Tan,Shibo Ma,Xiaoyu Zhao,Yushi Li,Chen Zhao,Yujun Zhu
Bimetallic W a CeO x (a = 0.06, 0.12, 0.18, 0.24) catalysts were synthesized for selective catalytic reduction of NO x with NH 3 (NH 3 -SCR). The influences of W on structure, activity and surface properties were investigated by XRF, XRD, Raman, TEM, N 2 adsorption-desorption, H 2 -TPR, O 2 /NH 3 /SO 2 -TPD, XPS, and in-situ DRIFTS. The characterization results show that the W/Ce ratio has a great effect on the NH 3 -SCR activity. The different catalytic activities of W a CeO x are mainly attributed to the acidity change, especially the increase of B-acid content plays a major role in enhancing low temperature activity. W 0.18 CeO x exhibits excellent low-temperature NH 3 -SCR activity, SO 2 /H 2 O resistance and N 2 selectivity with a broad activity window (190–490 °C) with 5%H 2 O. Moreover, good activity window (235–460 °C) can be maintained even the catalyst treated with 5% H 2 O at 800 °C for 12 h, showing especial hydrothermal stability. Thus, it can be summarized that W 0.18 CeO x is regarded as outstanding catalyst for low-temperature NH 3 -SCR of NO.
研究领域:
催化化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Xiaoqing Zhang,Yuewen Shao,Kai Sun,Mengjiao Fan,Shu Zhang,Xun Hu
Nickel-based catalysts are widely used in hydrogenation of varied types of organics. However, the nickel catalyst, like Ni/SiO 2 , lacks selectivity for hydrogenation of C=C and C=O. This is undesirable in some scenarios, such as conversion of biomass-derived furfuryl alcohol (FA) to cyclopentanone (CPO), a fine chemical, in which the C=C in furan ring of FA needs to be retained. In this study, introduction of sulfur species to Ni/SiO 2 catalyst via loading NiSO 4 was adopted to inhibit hydrogenation of furan ring in FA, aiming to achieve conversion of FA to CPO via ring-opening route. The results indicated that NiSO 4 was reduced to Ni x S y , which further reacted with metallic Ni, forming Ni 3 S 2 species and introducing the acidic sites with high-strength. The co-existence of Ni x S y and metallic Ni species effectively hindered hydrogenation of furan ring in FA, reducing tetrahydrofurfuryl alcohol (THFA) yield from 97% over Ni/SiO 2 to 0 over the NiS x /SiO 2 catalysts and shifting the major product to CPO. Nonetheless, the enhanced acidic sites along with the introduction of NiSO 4 catalyzed polymerization of reaction intermediates, competing with the production of CPO. The acidic sites, however, facilitated hydrogenolysis of vanillyl alcohol to selectively produce (yield: 94.3%) in hydrogenation of vanillin. Characterization of hydrogenation of FA with in-situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) technique suggested the oxygen-containing functionalities in FA, instead of furan ring, could strongly adsorb on the NiS 10 /SiO 2 catalyst, enhancing rearrangement reaction to form CPO while suppressing hydrogenation of the furan ring.
研究领域:
催化化学
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生物质转化
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材料科学
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DOI
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
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2020
·Vol. 31
·期 8
·1597-1604
·
IF 1.399
Ma Tianlin,Ding Jianfei,Liu Xueli,Zheng Jiandong,Yun Zhi
Gas phase conversion of glycerol to acrolein over a variety of aluminum phosphate (AlP) catalysts synthesized by a simple replacement reaction method with a variation in calcination temperature (300-700 ºC, AlP-300, AlP-400, AlP-500, AlP-600, and AlP-700, respectively) has been investigated. The textural properties, acidities and coke contents of the samples were also determined. The catalysts were presented in an amorphous state when the AlP sample was calcined below 500 ºC. Further increasing the calcination temperature promoted the formation of orthorhombic α-AlPO4 crystal. The weak acid sites increased when the calcination temperature was raised from 300 to 500 ºC. However, the weak acid sites decreased when the AlP was calcined above 500 ºC. The acidity of the catalyst played a crucial role in the glycerol dehydration reaction. The maximum acrolein selectivity of 66% at 98% glycerol conversion was obtained over AlP-500 catalyst, due to the largest number of acid sites and appropriate textural properties. AlP-700 exhibited the lowest glycerol conversion, owing to the formation of orthorhombic α-AlPO4 crystalline phase and the lowest amount of acid sites under high calcination temperature. The significant reduction in the acidity of the used sample led to a decrease of glycerol conversion.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）