CHINESE JOURNAL OF CATALYSIS
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2018
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IF 3.525
Wenjin Xu,Guangxu Zhang,Hanwei Chen,Guomeng Zhang,Yang Han,Yichuan Chang,Peng Gong
Two series of Mn/beta and Mn/ZSM-5 catalysts were prepared to study the influence of how different Mn precursors, introduced to the respective parent zeolites by wet impregnation, affected the selective catalytic reduction (SCR) of NO by NH 3 across a low reaction temperature window of 50–350 °C. In this study, the catalysts were characterized using N 2 adsorption/desorption, X-ray diffraction, X-ray fluorescence, H 2 temperature-programmed reduction, NH 3 temperature-programmed desorption and X-ray photoelectron spectroscopy. As the manganese chloride precursor only partially decomposed this primarily resulted in the formation of MnCl 2 in addition to the presence of low levels of crystalline Mn 3 O 4 , which resulted in poor catalytic performance. However, the manganese nitrate precursor formed crystalline MnO 2 as the major phase in addition to a minor presence of unconverted Mn-nitrate. Furthermore, manganese acetate resulted principally in a mixture of amorphous Mn 2 O 3 and MnO 2 , and crystalline Mn 3 O 4 . From all the catalysts screened, the test performance data showed Mn/beta-Ac to exhibit the highest NO conversion (97.5%) at 240 °C, which remained >90% across a temperature window of 220–350 °C. The excellent catalytic performance was ascribed to the enrichment of highly dispersed MnO x (Mn 2 O 3 and MnO 2 ) species that act as the active phase in the NH 3 -SCR process. Furthermore, together with a suitable amount of weakly acidic centers, higher concentration of surface manganese and a greater presence of surface labile oxygen groups, SCR performance was collectively enhanced at low temperature.
研究领域:
环境科学
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催化化学
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DOI
高影响因子
CATALYSIS LETTERS
·
2023
·Vol. 153
·期 12
·3837-3845
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IF 2.8
Wang Xue,Duan Zuqin,Wei Richu,Lei Qian,Chen Honglin
Trioxane (TOX), which is usually produced from formaldehyde catalyzed by acid-catalysts, is an important polymerizing monomer to produce high-performance plastics polyoxymethylene polymers (POMs). In order to reduce the separation cost and increase the catalytic activity, hierarchical Beta zeolites with different pore size were synthesized by PDDA and used for TOX produce from formaldehyde in this work. Hierarchical Beta zeolites’ average pore size increased with the increasing of PDDAs’ molecular weight. Compare to conventional Beta zeolite, it exhibited a higher catalytic performance with 95.13% selectivity and 2118 g/kg/h space–time yield of TOX due to its excellent diffusion performance from extra mesopore. The HCHO conversion and space–time yield of TOX increase first and then decrease with the pore size increasing. Further research showed that the decrease of catalytic activity is mainly due to the increase of extra-framework Al percent. This work illustrates the influence of both pore size and extra-framework Al content in hierarchical Beta zeolites for TOX produce from formaldehyde reaction. Graphical Abstract
研究领域:
化学工程
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材料科学
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催化
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产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
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2019
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IF 4.182
Qingrun Meng,Jiaxu Liu,Guang Xiong,Xinyao Li,Liping Liu,Hongchen Guo
The Sn-Beta zeolite is an efficient Lewis acid catalyst for a wide range of chemical reactions. Here a seed-free aerosol-assisted hydrothermal strategy is used to synthesize plate-like Sn-Beta zeolite with higher tin content. A majority of Sn species were transformed into the framework of Beta zeolite as the desired tetrahedral coordination state, which creates strong Lewis acid sites. Moreover, the diffusion property of the Sn-Beta zeolite can be further improved by a mild base-surfactant (NH 3 ˙ H 2 O-CTAB) treatment. The addition of CTAB can not only narrow the mesopore distribution but also prevent the excessive loss of Sn species. The obtained hierarchical Sn-Beta zeolite exhibits an enhanced catalytic performance in the Baeyer–Villiger oxidation of bulky ketone.
研究领域:
催化材料
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化学工程
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纳米材料合成
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DOI
高影响因子
CRYSTENGCOMM
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2019
·Vol. 22
·期 5
·945-954
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IF 3.382
Lanjian Xu,Yangyang Yuan,Jie Zhang,Yanfei Zhang,Xiaomin Zhang,Lei Chen,Lei Xu
A green, cost-effective and facile steam-assisted crystallization (SAC) strategy was developed to synthesize core–shell-structured zeolite composites with different frameworks between the core and shell. Chemical incompatibility from different structures has been circumvented by dip-coating Silicalite-1 seeds and an in situ transformation process. Beta@Silicalite-1 zeolites with a nanoscale polycrystal Silicalite-1 shell wrapped around the monocrystal Beta core was synthesized. The crystallization process and synthetic parameters, such as the composition of the core, crystallization temperature and gel composition of the seed solution, were investigated. The results revealed the importance of stability of the core and the crystallization rate of the Silicalite-1 shell. Interestingly, a trace amount of aluminum in the core zeolite could help resist corrosion during crystallization. Further investigation on alkylation and etherification reactions over Beta@Silicalite-1 demonstrated the advantage in selectivity control toward self-etherification versus alkylation.
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2022
·
IF 4.889
Guilin Liu,Feng Xin,Chen Cao,Xubin Zhang,Qian Lei,Honglin Chen,Hailun Ren
Poly(oxymethylene) dimethyl ethers (PODE n=3-5 ), as promising diesel additive, were synthesized by reaction of 1,3,5-Trioxan (TOX) and methylal (PODE 1 ) on the catalyst of zeolite BETA in a fixed-bed reactor and kinetically researched under reaction temperature from 308 to 358 K, initial mole ratio 3∙ N TOX / N PODE1 from 0.8 to 1.2, space time from 0.33 to 20.78 min⋅kg⋅l −1 and water content from 0 to 2 wt %. A series of rate laws were formulated for quantifying not only their reaction rates but also the role of water. The obtained activation energies of propagation and decomposition reactions of PODE n (n = 3 ∼ 8) are 22.89 kJ⋅mol −1 and 27.46 kJ⋅mol −1 respectively, and their pre-exponential factors depend on the “n” in PODE n . Through optimizing the Schulz-Flory distribution of PODE n based on the kinetics, the maximal selectivity of TOX to PODE 3-5 of 57.80% will achieve under anhydrous conditions, while this will become 54.60% under 5 wt % water in TOX.
研究领域:
化学工程
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催化反应
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
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2025
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IF 4.8
Jin Mengyu,Wu Detong,Song Yuanbo,Shi Yang,Wang Xiaoxia,Shen Zheng,Zhang Yalei
This study presents an efficient strategy for converting high-boiling solvent (HBS) pretreated cellulose into lactic acid (LA) over a Cr-Sn-Beta bimetallic catalyst synthesized by flash Joule heating (FJH). Ethylene glycol-based HBS pretreatment effectively enriched cellulose content in straw, while the FJH method enabled rapid and uniform metal incorporation. The resulting Cr-Sn-Beta catalyst exhibited a maximum LA yield of 33.54% with a carbon balance of 90.08%, showing high selectivity and catalytic efficiency. The synergistic function of Cr and Sn acid sites was also evaluated. This work provides a promising route for biomass valorization and catalyst design via combined pretreatment and advanced synthesis techniques.
研究领域:
催化
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生物质转化
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材料科学
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化学工程
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产品关联
DOI
高影响因子
CHEMOSPHERE
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2020
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IF 5.778
Jiuhu Zhao,Gaige Zhang,Jiansheng He,Zhengzhong Wen,Zhi Li,Tingkun Gu,Ran Ding,Yongji Zhu,Rongshu Zhu
In/H-Beta catalyst was prepared by optimizing the support, concentration of ion exchange liquid and calcination temperature to investigate the effects of synthesis conditions on catalytic activity of selective catalytic reduction of NO x with CH 4 . The results showed that the In/H-Beta catalyst exhibited the superior activity when concentration of exchange liquid was 0.033 M and calcination temperature was 500 °C, the NO x removal ratio could reach 97.6%. In addition, reaction conditions could affect the catalytic performance. When O 2 concentration was 10%, CH 4 :NO ratio was no less than one, space velocity was lower than 23600 h −1 and NO initial concentration was no more than 700 ppm, In/H-Beta could exhibit superior catalytic activity. Moreover, the catalytic performances of In/H-Beta catalysts were discussed after enduring H 2 O or/and SO 2 . This novel strategy could open the door for selective catalytic reduction of NO x with CH 4 .
研究领域:
环境科学
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催化化学
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产品关联
DOI
PubMed
高影响因子
Catalysis Science & Technology
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2020
·Vol. 10
·期 24
·8437-8444
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IF 5.721
Xiaomei Yang,Liuyong Wang,Tianliang Lu,Beibei Gao,Yunlai Su,Lipeng Zhou
Hydrothermally synthesized Sn-Beta is an excellent catalyst for the conversion of sugars to alkyl lactates. However, its catalytic performance is highly dependent on the synthesis parameters. In this work, the effects of the synthesis parameters such as the water amount of the synthesis gel and the crystallization time on the synthesis and properties and catalytic performance of Sn-Beta in the conversion of glucose to methyl lactate (MLA) were investigated. The crystallization rate was accelerated remarkably by reducing the water amount of the synthesis gel. With the aid of the Si-Beta seed, Sn-Beta was almost fully-crystallized after one day with nH2O/nSiO2 of 4.5, but seven days were needed with nH2O/nSiO2 of 7.5. However, Sn-Beta synthesized with nH2O/nSiO2 of 4.5 has more extraframework SnO2 due to the fast formation of the *BEA structure and the slow incorporation of Sn4+ into the framework sites, which resulted in the lower activity of MLA formation. More Sn4+ species were incorporated into the framework sites and thus more Lewis acid sites were generated with increasing crystallization time. At the same time, the ratio of open to closed Sn sites (RO/C) increased, which led to the decrease in the activity of MLA formation and due to that, the open Sn site with a proximal silanol is unfavorable for the conversion of glucose to MLA. During recycling study, it is surprisingly found that the yield of MLA increased gradually over the fully-crystallized Sn-Beta catalyst. Characterization results of the recovered catalyst from the eighth run indicate that the structure was preserved well, but the value of RO/C reduced due to the change of the state and microenvironment of Sn species.
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
高影响因子
ENERGY
·
2025
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IF 9.4
Qi Zhou,Liu Wu,Jingyue Wang,Jie Liang
Lignin, with its complex structure and high stability, poses a significant challenge in the directed depolymerization to obtain aromatic-rich bio-oil. To prevent the formation of hard-shelled char resulting from the melting and agglomeration of lignin during pyrolysis, this study proposed a dual strategy combining Ca(OH) 2 pretreatment and Beta zeolite, which demonstrated a synergistic effect through β-O-4 bond cleavage, effectively suppressing lignin condensation while achieving high aromatic selectivity. In this study, the influence of various operational parameters was examined. Key variables including pretreatment procedures, concentration levels, catalyst selection, catalyst-to-raw material ratio, carrier gas velocity, and pyrolysis thermal conditions were analyzed to determine their effects on the critical processes. Pretreatment with 5 wt% Ca(OH) 2 significantly reduced lignin agglomeration during pyrolysis. Using Beta zeolite (1:1 mass ratio) in CFP at 500 °C with 75 mL/min carrier gas flow increased bio-oil yield from 5.0 wt% to 7.5 wt% and enhanced aromatic selectivity from 1.9 area% to 84.9 area%. Using 2-phenoxy-1-phenylethanol (α-OH-PPE) as a model compound, we found Ca(OH) 2 pretreatment and Beta zeolite together enhanced β-O-4 bond cleavage in lignin. This synergistic approach facilitated efficient bond cleavage and showed remarkable effectiveness in aromatic production.
研究领域:
化学工程
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可再生能源
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生物质转化
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产品关联
DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Gen Li,Yunqi Hu,Zhaojun Liu,Yanlei Sha,Chenyang Zhao,Honghai Liu,Xinye Fan,Pingyu Wan,Hongjuan Zhao,Hongtao Liu
The introduction of mesoporosity is of great importance because mass-transportation limitations within microporous systems hinder their catalytic performance. The direct formation of mesoporosity in zeolite is generally achieved through the use of an additional and expensive organic template, which limits its industrial applications. In this investigation, we reported a facile procedure for synthesizing zeolite Beta with micromesoporosity, in which tetraethylammonium hydroxide (TEAOH)/crystal seeds (CS) worked as the micropore-directing agents, assisted by simple citric acid (CA) containing hydroxyl carboxylic groups. The working mechanism of TEAOH/CS/CA was proposed on the basis of various characterization methods. Oxalic acid was employed as an additional template to further elucidate the formation mechanism of the mesopores. The formation mechanism is proposed that CA with hydroxyl carboxylic groups can interact with aluminosilicate and TEAOH simultaneously to form a semimicelle, leading to the final mesostructure. The resultant mesoporous material was tested in the esterification reaction of benzyl alcohol and acetic acid. Improved activity and selectivity were observed as a result of the introduction of intracrystalline mesopores, suggesting the superiority of the CA-assisted zeolite Beta. This novel procedure provides a simple procedure for obtaining zeolite Beta with hierarchical pores, which can enable the economic and environmentally friendly production of hierarchical zeolites for industrial applications.
研究领域:
材料科学
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催化
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化学合成
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多孔材料
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工业化学
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产品关联
DOI
PubMed
高影响因子
ChemElectroChem
·
2017
·Vol. 4
·期 6
·1279-1286
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IF 4.136
Jinling Zhou,Tongguang Ge,Xiangzhi Cui,Jian Lv,Hangle Guo,Zile Hua,Jianlin Shi
Graphical Upping the pace : A novel precious-metal-free cathode catalyst, Co 3 O 4 nanoparticle-incorporated m -Beta zeolite, is synthesized and used to speed up the sluggish oxygen reduction reaction through a synergistic catalytic effect. Cost-efficient and high-performance oxygen reduction electrocatalysts are widely pursued to boost the sluggish oxygen reduction reaction (ORR) for renewable-energy technology applications. Here, a novel precious-metal-free cathode catalyst, Co 3 O 4 nanoparticle-incorporated mesoporous Beta zeolite, was first synthesized by using a facile steam-assisted crystallization (SAC) and hydrothermal approach. Owning to the synergetic catalytic effects between the Co 3 O 4 nanoparticles and the mesoporous Beta matrix, the resulting Co 3 O 4 / m -Beta nanocomposites catalyst showed comparable ORR electrochemical catalytic activity to the benchmark 20 wt% Pt/C catalyst with a high onset potential of 0.88 V, and much higher methanol tolerance with a negligible negative shift of the peak potential and excellent electrochemical stability in alkaline media. The relatively higher surface Co 2+ concentration and the abundant Brønsted acid sites facilitate the ORR process, mainly through a 4e − pathway, which makes the Co 3 O 4 / m -Beta nanocomposite a favorable candidate for improving energy storage and conversion efficiencies in fuel cells.
研究领域:
材料科学
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电化学
·
能源技术
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Weiping Liao,Haoyi Lin,Jiaxing Zhang,Jiaqi Wang,Kaixuan Yang,Ting Su,Hongying Lü,Zhiguo Zhu
2,5-Furandicarboxylic acid (FDCA) is a potential substitute of petroleum-based terephthalic acid to manufacture polymer. The selective aerobic oxidation of renewable 5-hydroxymethylfurfural (HMF) to FDCA is a promising and appealing route for establishing sustainable and environmentally friendly chemical process. Au catalysts have exhibited exceptional catalytic performances for this highly anticipated chemical transformation, where the used support intensively impacts the catalytic productivity from the standpoint of metal-support and guest organic-support interactions. Herein, Sn-Beta zeolite was straightforward and rapidly synthesized via structural reconstruction without the auxiliary of any solvents, which was adopted as support for Au catalyst to construct bifunctional catalysts. As for Au/Sn-Beta sample, Lewis acid sites were related to Sn 4+ ions in the zeolite framework, while electronic properties and particle size of Au species were capable of being modulated by Au dosages. In addition, charge transfer from Au species to framework Sn 4+ ions resulted in the formation of Au δ+ species. Au/Sn-Beta catalyst with metal-Lewis acid cooperative active sites showed unique catalytic productivity of FDCA product in the aerobic oxidation of HMF to FDCA, whose catalytic performance was correlated with Lewis acid amounts as well as geometric and electronic effect of Au particle. Reaction mechanism analysis revealed the pathway and concrete step that Lewis acid site functioned. The aim is to provide some guidance for constructing a task-specific multifunctional supported catalyst from the view of support-enhanced effect for the catalytic conversion of biomass resource with multi-functional-groups.
研究领域:
催化化学
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材料科学
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环境科学
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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）