Reaction Chemistry & Engineering
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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
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DOI
高影响因子
Progress in Natural Science-Materials International
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2020
·
IF 4
D.F. Wu,L.Z. Ouyang,J.M. Huang,J.W. Liu,H. Wang,X.S. Yang,H. Shao,M. Zhu
Hydrolysis of Zr(BH 4 ) 4 ·8NH 3 in deionized water can generate high purity hydrogen at room temperature. However, the sluggish hydrolysis kinetics of Zr(BH 4 ) 4 ·8NH 3 hinders its practical use. To improve its hydrogen generation properties, the effects of magnetic stirring, changing hydrolysis solution and tuning the ammonia coordination number on the hydrolysis properties of Zr(BH 4 ) 4 ·8NH 3 were investigated. Results show that both changing hydrolysis solution and tuning the ammonia coordination number can enhance the hydrolysis kinetics. The hydrolysis kinetics properties of Zr(BH 4 ) 4 ·8NH 3 were significantly improved in MgCl 2 and CoCl 2 solutions. The Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8) samples were synthesized by a ball-milling method with different ammonization time (10, 60 and 180 min). Both the hydrolysis kinetics and hydrogen yield of Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8) were enhanced as the ammonia coordination number (x) decreased. Thus, tuning ammonia coordination number is an effective way to control the hydrolysis properties of Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8).
研究领域:
材料科学
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化学工程
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DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Can Sun,Shouxin Zhu,Jingyi Qu,Zhexiao Zhu,Yutong Chen,Xuewei Tu,Wenya Cai,Zhiqin Yu,Yibin Liu,Shijie Zhang,Hui Zheng
Photocatalytic nitrogen fixation is seen to be a potential technology for nitrogen reduction due to its eco-friendliness, low energy consumption, and environmental protection. In this study, photocatalysts with abundant oxygen vacancies (Zr-naphthalene dicarboxylic acid (Zr-NDC) and Zr-phthalic acid (Zr-BDC)) were designed using 1,4-naphthalene dicarboxylic acid (H 2 NDC) and 1,4-phthalic acid (H 2 BDC) as ligands. Since the structure of H 2 NDC includes one extra benzene ring than H 2 BDC, the charge density differential of the organic ligand is probably altered. The hypothesis is proved by density function theory (DFT) calculation. The abundant oxygen vacancies of the catalyst offer numerous active sites for nitrogen fixation. Concurrently, the process of ligand–metal charge transfer facilitates photo-electron transfer, creating an active center for nitrogen reduction. Additionally, the functionalization of ligand amplifies another pathway for charge transfer, broadening the light absorption range of Metal-organic framework (MOF) and increasing its capacity for nitrogen reduction. In contrast to H 2 BDC, the benzene ring added in H 2 NDC structure acts as an electron energy storage tank with a stronger electron density difference favorable for photogenerated electron-hole separation resulting in higher photocatalytic activity in Zr-NDC. The experimental results show that the nitrogen fixation efficiency of Zr-NDC is 163.7 µmol g −1 h −1 , which is significantly better than that of Zr-BDC (29.3 µmol g −1 h −1 ). This work utilizes cost-effective and non-toxic ingredients to design highly efficient photocatalysts, thereby significantly contributing to the practical implementation of green chemistry principles.
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
Arabian Journal of Chemistry
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2023
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IF 6
Hongru Zhao,Chengqiang Hu,Na Sui,Xinyu Liu,Junlian Wang
Zr/Hf separation has always been a great challenge. Although the methyl isobutyl ketone (MIBK)-thiocyanic acid (HSCN) extraction system selectively extracts Hf over Zr and can realize Zr/Hf separation, it has the following disadvantages: it has a strong smell; it is easy to burn; and there is large loss of extractant during extraction due to the low boiling point (115.7 °C), low flashing point (13 °C), and high solubility of MIBK in water (1.7 % at 25 °C). In this study, Zr/Hf separation performance by MIBK homologues — of which one side of C = O is iso pentyl, iso hexyl, n -pentyl, n -hexyl or n -heptyl, while the other side are all methyl — were studied and compared with MIBK. Effects of HSCN pre-extraction, HCl concentration, NH 4 SCN concentration on Zr, Hf extraction and separation performance were investigated. Relationships between methyl alkyl ketone structure and their Zr/Hf separation performance were revealed. A new Zr/Hf separation system MNPK (methyl n -pentyl ketone)-HSCN was found. MNPK has a higher boiling point (151 °C), a higher flashing point (47 °C) and a lower solubility in water (0.43 % at 20 °C) than MIBK. Compared to MIBK, it is safer, more friendly operation environments and less extractant loss during extraction. MNPK has as fast extraction kinetics as MIBK. It also has good anti-emulsification performance. Its maximum β Hf/Zr can reach to 12.61. The loaded Zr and Hf in MNPK have very similar stripping behaviors with those loaded in MIBK by HCl and H 2 SO 4 solutions, respectively. MNPK is the most possible candidate to replace MIBK from HSCN media in Zr/Hf separation industry.
研究领域:
化学工程
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材料科学
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DOI
高影响因子
Catalysts
·
2020
·Vol. 10
·期 4
·384
·
IF 3.52
Pei Yu,Can Chen,Guangci Li,Zhong Wang,Xuebing Li
The esterification of malic acid using traditional homogenous catalysts suffers from the difficulty in reuse of the catalyst and undesirable side reactions. In this work, Zr(SO4)2/SiO2and Zr(SO4)2/activated carbon (AC) as solid acid catalysts were prepared for malic acid esterification with methanol. The conversion of malic acid over these two catalysts is comparable to that over H2SO4and unsupported Zr(SO4)2∙4H2O catalysts; however; a 99% selectivity of dimethyl malate can be realized on these two supported catalysts, which is much higher than that of conventional H2SO4(75%) and unsupported Zr(SO4)2∙4H2O (80%) catalysts, highlighting the critical role of AC and SiO2supports in tuning the selectivity. We suggest that the surface hydroxyls of AC or lattice O2−ions from SiO2donate electrons to Zr4+in Zr(SO4)2/AC and Zr(SO4)2/SiO2catalysts, which results in the increase in electron density on Zr4+. The enhanced electron density on Zr4+reduces the degree of H delocalization from crystal water and then decreases the Brønsted acid strength. Consequently, the reduced Brønsted acid strength of Zr(SO4)2/AC and Zr(SO4)2/SiO2catalysts suppresses the intermolecular dehydration side reaction. In addition, these two supported catalysts can be easily separated from the reaction system by simple filtration with almost no loss of activity.Keywords:malic acid;catalytic esterification;solid acid catalyst;Zr(SO4)2;intermolecular dehydration
研究领域:
催化
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化学工程
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有机化学
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DOI
高影响因子
iScience
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2024
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IF 4.6
Jielin Huang,Jie Wang,Haonan Duan,Li Dong,Songsong Chen,Junping Zhang,Xiangping Zhang
Acidic and basic sites of catalysts are essential for CO 2 capture and activation. In this work, Zr, N-ZnO/ZnAl-LDH-IL composites in ionic liquid and methanol systems were fabricated, and applied to catalyze the synthesis of ethylene carbonate (EC) from ethylene glycol (EG) and CO 2 with about 4.76 mmol EC g Cat. −1 h −1 . The composites showed more strong basic sites due to the effective induction of reactive groups on the catalyst surface by Zr doping, resulting in an increase of pyridinic-N groups from 5.48% to 22.25%. More C atoms adjacent to pyridinic-N as strong basic sites was conducive to the activation of CO 2 and EG. In addition, the possible catalytic pathway and mechanism of the composites for synthesizing EC as well as the doping of La, Fe, Ce, and Cu were also investigated, which provides an effective strategy for regulating the acid-base centers on the catalyst surface through ionic liquids and methanol solvents.
研究领域:
催化化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
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2023
·
IF 4.6
Jianhong Zheng,Xi Chen,Xiaoxiao Yin,Kai Chen,Aili Liu,Xiaochun Yu,Shun Wang,Zhongwei Chen
A highly efficient and organic solvent-free synthetic strategy for the selective oxidation of anilines to azoxybenzenes was developed by employing porous Zr-MOFs as catalysts in aqueous hydrogen peroxide solution. The impact of cluster nodes, pore size, and linker functionalities on the catalytic performance of Zr-MOFs was fully evaluated and discussed. Featuring abundant bridging Zr-OH-Zr catalytic sites and confined microenvironments, the pristine UiO-66(Zr) could create abundant reactive oxygen species (ROS) with high H 2 O 2 efficiency, affording quantitative yield of azoxybenzene under mild conditions. Furthermore, the UiO-66(Zr)/H 2 O 2 heterogeneous catalytic system exhibited broad and size-selective substrate scope and excellent stability in consecutive catalytic cycles. Mechanism studies demonstrated that the azoxybenzenes were produced through radical pathway on bridging Zr-OH-Zr sites. This study provided alternative strategies exploiting green catalytic systems with porous MOFs, which might further expand the potential application of the MOFs family.
研究领域:
化学
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材料科学
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DOI
高影响因子
ChemCatChem
·
2023
·Vol. 15
·期 5
·e202201352
·
IF 4.5
Qingpo Peng,Yongjun Jiang,Bei-Bei Xu,Xiuge Zhao,Sheng Dai,Ye-Feng Yao,Zhenshan Hou
Graphical Zr oxo cluster bifunctional catalyst : The Zr oxo cluster [Zr 6 O 4 (OH) 4 (HSCH 2 CH 2 COO) 12 ] 2 has been developed, and then the molecular catalyst with Lewis acid and Brönsted acid sites were attained by the oxidation of the sulfhydryl group of the Zr oxo cluster with H 2 O 2 . The resulting bifunctional catalyst showed a superior catalytic activity for alcoholysis of furfural to alkyl levulinates. A novel dodecanuclear Zr oxo cluster [Zr 6 O 4 (OH) 4 (HSCH 2 CH 2 COO) 12 ] 2 (ZrO-SH-10) has been constructed under the room temperature, followed by oxidation of the sulfhydryl group with H 2 O 2 to achieve a bifunctional catalyst with Lewis acid and Brönsted acid sites. The characterization of catalysts indicated that {Zr 6 O 4 } cluster core can be stabilized with a shell of carboxylate ligands, and the resulting ZrO-SO 3 H was formed as a discrete molecular catalyst, exhibiting superior activity and recyclability for the cascade conversion of furfural to alkyl levulinate by the integration of transfer hydrogenation and alcoholysis in n-butanol. The yield of n-butyl levulinate can achieve as high as 91 % under the optimum conditions. Meanwhile, no leaching of the active species was found, which confirmed the structure of the Zr oxo cluster was air and moisture-stable. On the basis of the studies on the reaction kinetics and isotope tracking, the reaction mechanism was proposed accordingly.
研究领域:
化学
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催化科学
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产品关联
DOI
高影响因子
Molecular Catalysis
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2024
·
IF 3.9
Haoxi Jiang,Hanwen Gu,Lingtao Wang,Guochao Yang
Zr-BEA zeolite was introduced to the aldol condensation of acetaldehyde and showed high crotonaldehyde selectivity (over 85%), but it suffered from rapid deactivation, where the conversion of acetaldehyde decreased from 16.4% at 1 h to 6.5% at 8 h. The spent Zr-BEA zeolites at different time-on-stream (TOS = 1, 2, 4, 6, and 8 h) were characterized by SEM, XRD, XPS, FT-IR, TGA, N 2 physical adsorption, and GC–MS to understand the deactivation mechanism. Pore blocking and Zr active site coverage caused by carbonaceous deposits were both responsible for the deactivation. Furthermore, the main carbonaceous species were unsaturated aldehydes, unsaturated ketones, and aromatic compounds.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2024
·Vol. 48
·期 45
·19220-19228
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IF 2.7
Peng Lu,Qianwen Hu,Kui Wang,Shiyong Chen,Zongxiao Li,Xinjie Chen,Chuang Xing,Yanhong Wang,Ce Du
The efficient CO2 conversion to light olefins through hydrogenation is a feasible strategy to achieve carbon neutrality goals. Herein, a series of bimetallic Zn–Zr/supports are synthesized by a conventional impregnation method. We demonstrate that different supports endow catalysts with various specific surface areas, pore sizes, chemical adsorption performances, and acid densities. The effects of different support-loaded Zn–Zr coupled with SAPO-34 on CO2 hydrogenation to light olefins are investigated systematically. The CO2 conversion of Zn–Zr/Q10-SAPO-34, Zn–Zr/Q50-SAPO-34, Zn–Zr/γAl2O3-SAPO-34, Zn–Zr/MgO-SAPO-34 and Zn–Zr/S-1-SAPO-34 is 11.4%, 9.2%, 24.0%, 8.8%, and 16.2%, respectively, with corresponding light olefin selectivity of 39.0%, 28.1%, 30.4%, 4.8%, and 14.7%, respectively. Significantly, γAl2O3 is more conducive to CO2 conversion, while Q10 tends to produce light olefins. This work provides an effective reference for support selection in CO2 hydrogenation to light olefins.
研究领域:
化学工程
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环境科学
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2022
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IF 9.136
Mao Fu,Xuepeng Deng,Shi-Qiang Wang,Fenglin Yang,Li-Chiang Lin,Michael J. Zaworotko,Yingchao Dong
To find sustainable water solutions, the development of high capacity, scalable robust adsorbents and mechanistic insight about their performance offers the potential to effectively address the global challenges of water scarcity and water contamination. We herein rationally design Zr-cluster defective MOF-808 (MOF-808 def ) with exposed carboxyl groups, a robust zirconium metal–organic framework (Zr-MOF), exhibiting high adsorption capacity (q max ∼ 296 mg·g −1 ) coupled with high selectivitity for tetracycline (TC) antibiotics, outperforming other water-stable MOFs, commercial and inorganic nano-adsorbents. MOF-808 def functions well across a wide range of contaminant concentrations (from trace to high-concentration) and even in harsh conditions ( e.g. , high acidity and salinity). Both experimental and simulation results indicate that the mechanism of adsorption involves both physisorption and chemisorption via hydrogen bonding, electrostatic interactions (EIs) and C-O-C covalent bonding via esterification. Computational studies confirm that hydrogen bonding plays a key role in strong guest–host interactions between TCs and MOF-808 def . Further, defects resulting from missing-Zr-clusters in MOF-808 def are confirmed to enhance adsorption performance. Specifically, the defect sites present exposed carboxyl groups from MOF-808 def linker ligands that selectively react with –OH groups (phenol and tertiary alcohol moieties) in TC via esterification. These defects drive highly selective adsorption even at low concentrations of TCs ( e.g. , 500 ppb). Aiming for more than enhanced performance, economic estimation and scalable engineered reactor tests revealed that MOF-808 def and its nano-composites are free of environmental risks and offer promise for sustainable water treatment at pilot scale. The use of defect-engineering rationales is a molecule-level design concept that could be generally useful for the development of the next generation of MOF-based nano-adsorbents for sustainable water treatment applications.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2025
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IF 6.2
Yuqiang Liang,Hongzhi Cheng,Yujie Zhang,Junyang Jin,Yang Wang,Jian Gu,Jian Yang,Yinsheng Li
A novel amorphous Zr-MOFs (aZMs) was synthesized using ZrCl 4 and C 10 H 6 O 8 , with deionized water and ethanol as solvents. ZrC nanoparticles were successfully synthesized by pyrolyzing aZMs precursors via one-step thermal decomposition. Effects of metal/linker molar ratios and pyrolysis temperatures on the composition and microstructure of ZrC powders were investigated, meanwhile, the synthesis mechanisms were also discussed. High-purity spherical ZrC nanoparticles (104.2 ± 21.5 nm) were obtained by pyrolyzing the aZMs with metal/linker molar ratio of 2 at 1500 °C. Notably, additive-free dense ZrC ceramic were fabricated using precursor-derived ZrC nanoparticles at 1900 °C for 1 h with a pressure of 30 MPa by SPS, achieving a high relative density (96.2 %) and Vickers hardness (15.9 GPa). Compared with commercially available ZrC ceramic (93.3 %, 12.79 GPa), the as-sintered ZrC ceramic exhibited better sinterability and higher hardness. This work provides a promising potential for use in fabricating ZrC-based ultra-high temperature ceramics and composites.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）