JOURNAL OF POROUS MATERIALS
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2022
·Vol. 29
·期 4
·1039-1047
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IF 2.523
Yang Zhigang,Li Yanru,Wang Dongliang,Long Xuefeng,Li Hongwei,Zhao Xinhong
Currently, synthesizing zeolites with specific physicochemical properties in a more environmentally benign and safe way is challenging. Herein we report a novel ionothermal route of preparing HZSM-5 zeolite, which is featured by the direct interzeolite transformation of HY to HZSM-5. The appropriate synthetic conditions of this HZSM-5 material are refined. Although performing a series of optimization, the resultant product still contains minor (NH 4 ) 3 AlF 6 impurity. Pure HZSM-5 phase with high relative crystallinity can be obtained through successive calcination and acid-washing treatments towards the as-made sample. SEM–EDS characterization and nitrogen physisorption measurement reveal that this pure HZSM-5 sample is composed of classical coffin-like crystals with a low Si/Al ratio and evident hierarchical micro-mesoporous structure. Benefiting from its unique physicochemical properties, this pure HZSM-5 catalyst exhibits more superior methanol-to-aromatics performance than those of the state-of-the-art HZSM-5 and Metal/ZSM-5 catalysts evaluated under similar reaction conditions. It can be anticipated that this HZSM-5 material may be applied in other industrially relevant reactions owing to its particular structure and properties.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 15
·3933-3946
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IF 5.726
Ting Wang,Yuebing Xu,Chengming Shi,Feng Jiang,Bing Liu,Xiaohao Liu
Direct conversion of syngas (CO/H2) into aromatics over tandem catalysts via the Fischer–Tropsch synthesis (FTS) route has attracted much attention because of its high one-pass conversion and milder reaction conditions. However, the complicated FTS product composition leads to more difficult mechanistic elucidation of aromatics formation compared to the methanol route. Herein, a series of strategies, such as covering external surface acid sites of HZSM-5 with a layer of inert SiO2, layered loading of an FeMn FTS catalyst and HZSM-5 zeolite in one reactor and two tandem reactors, and model reactions with ethylene and propylene over zeolite in a simulated FTS reaction environment, were applied to unveil the reaction mechanism and related factors affecting aromatic selectivity. It was found that different from the methanol route, the tandem FeMn–HZSM-5 catalyst produced aromatics mainly from the conversion of C5+ FT intermediates rather than light olefins (C2=–C4=). SiO2 coating could remarkably enhance the para-xylene (PX) selectivity due to hindering of its isomerization to major meta- and minor ortho-xylene (MX and OX) on the external surface acid sites of HZSM-5 by releasing the space confinement. The layered loading experiments in one reactor demonstrated that a farther distance from the FTS catalyst to zeolite largely increased the selectivity to BTX (benzene, toluene and xylene) in total aromatics from 48.3% to 68.9% on a carbon molar basis by suppressing the alkylation reaction of benzene and toluene with ethylene due to an obviously lower local ethylene concentration on HZSM-5. FeMn and HZSM-5 with layered loading in two tandem reactors confirmed that light olefins (C2=–C4=) were mainly hydrogenated and isomerized into paraffins. The model reactions with ethylene and propylene in a simulated local FTS reaction environment revealed that the presence of H2O and CO2in situ produced from the FTS reaction played a crucial role in promoting the aromatics formation at obviously lower reaction temperature which resulted from the enhancing acid strength and the driving H transfer to facilitate the cyclization and dehydrogenation reaction. This study provides a clear perspective for the aromatics formation mechanism and the tuning of the aromatic selectivity.
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
Catalysis Science & Technology
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2018
·Vol. 8
·期 16
·4241-4256
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IF 5.365
Xiaochao Xian,Chao Ran,Peng Yang,Yirong Chu,Shuo Zhao,Lichun Dong
The effect of the acidity of HZSM-5/MCM-41 hierarchical zeolite on its catalytic performance in the supercritical catalytic cracking of n-dodecane was investigated by controlled ion exchange with NaCl solution under ultrasonic conditions. XRD and nitrogen adsorption–desorption results showed that the crystal and porous properties were not affected, while NH3-TPD, the probe reaction of n-hexane cracking and temperature-programmed surface reaction (TPSR) of n-dodecane demonstrated that strong Brønsted acid sites were replaced by Na+ (weak Lewis acid sites) to different extents with varying concentrations of NaCl solution. Although the initial conversion of n-dodecane during the supercritical catalytic cracking was slightly reduced, its stability was greatly enhanced by ion exchange. An ultrastable catalyst with no obvious deactivation within 3 h of time on stream (TOS) was obtained by ion exchange with 0.8 M NaCl solution. A mechanism describing the role of the acid sites residing in both micropores and mesopores of the hierarchical catalyst was proposed based on coke analysis.
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2018
·
IF 5.807
Zihao Zhang,Hao Cheng,Hao Chen,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
Modified H-type ZSM-5 (HZSM-5) catalysts were prepared using hexadecyl trimethyl ammonium bromide (CTAB) as mesopore templates to enhance the activity for the catalytic fast pyrolysis of rice straw for aromatics compounds. A certain quantity of CTAB added into the HZSM-5 (HZ) forming hierarchical structure exhibited an improvement in the yield of the aromatics and a decrease in the yield of coke in comparison with that of bare HZ. In contrast, excessive CTAB addition resulted in a decrease in aromatic yield and an increase in coke yield. The effects of crystallinity, textural properties, morphological structure and acidity distribution on the production of aromatic compounds were measured by XRD, BET, TEM and NH 3 -TPD. The good crystallinity, small amount of mesopore formation and highest total acidity discovered in HZ-0.01 (the mole ratio of CTAB/SiO 2 is 0.01) provided the highest aromatic compound yield of 26.8% and the lowest coke yield of 39.2%.
研究领域:
化学工程
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Environmental Chemical Engineering
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2025
·
IF 7.2
Weilun Yu,Xing You,Yuanchen Wu,Chuanpeng Li,Qiyao Wang,Xiaohang Yang,Xingbo Bian,Yi Lu
The most promising and environmentally friendly strategy to address the greenhouse effect is to utilize renewable solar energy and semiconductor photocatalytic technology to convert excessive CO₂ into valuable chemicals. However, the unsatisfactory photoreduction activity and product selectivity of pristine semiconductor remain significant barriers to their large-scale industrial application. In this study, graphitic carbon nitride (g-C 3 N 4 ) was selected as a model photocatalyst, and HZSM-5 zeolite with a high Si/Al ratio of 500 was employed to synthesize g-C 3 N 4 /HZSM-5 composite via a simple thermal polymerization method. The incorporation of HZSM-5 zeolite, characterized by its rich pore structure, significantly increased the composite's specific surface area, thereby reducing the transportation distance of photoexcited charge carriers and enhancing photoelectric conversion efficiency. The pore structure of HZSM-5 zeolite facilitated the enrichment of CO 2 , increasing the local reactant concentration. Additionally, the specific pore micro-environment exhibited a lower adsorption strength for the reduction product (CO), preventing its further conversion into undesired by-products. Furthermore, the weak acidity of the micro-environment contributed to the stabilization of intermediates, such as -HCO 3 and -COOH, promoting specific reaction pathways. As a result, the g-C 3 N 4 /HZSM-5 composite achieved high CO 2 photoreduction activity and CO selectivity (>95 %). This work highlights the potential of designing composite photocatalysts with tailored micro-environments for efficient and selective CO 2 photoreduction.
研究领域:
材料科学
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环境科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2017
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IF 5.951
Jia Ding,Pengjing Chen,Songyu Fan,Zhiqiang Zhang,Lupeng Han,Guofeng Zhao,Ye Liu,Yong Lu
Free-standing stainless-steel (SS)-fiber@meso-HZSM-5 core–shell catalysts engineered from micro- to macro-scale were highly efficiently synthesized via cost-effective steam-assisted crystallization (SAC) method. Impact of synthesis conditions on their morphology and textural/acidic properties was investigated by means of XRD, SEM, TEM, solid-state NMR, NH3-TPD, Py-IR and N2 physisorption. Single-run lifetime of such structured catalysts for MTP process was strongly dependent on their preparation conditions but slightly the product distribution. A volcano-like relationship for lifetime was observed against the SAC time, which was correlated well with the crystallization-time-dependent crystallinity, mesoporosity and crystal size. The promising SS-fiber@meso-HZSM-5 was the one obtained after the SAC for 12 h, which delivered a prolonged single-run lifetime of 620 h with a high propylene selectivity of ∼42% at 450 °C using a methanol weight hourly space velocity (WHSV) of 1 h–1, as the result of high crystallinity, well-developed mesoporosity and small crystal size. Note that well-developed mesoporosity was paramount for the catalyst stability improvement, because of enhanced accommodation capacity of zeolite shell for receiving formed coke.
研究领域:
化学工程
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催化材料
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2022
·
IF 5.723
Yitao Zhao,Junjun Cheng,Peng Zhang,Xinhui Liu,Jianguo Zhuang,Yijun Yu,Qichao Zhao,Yuchen Wang,Xuedong Zhu,Fan Yang
Alkylation of benzene with carbon dioxide (CO 2 ) is significant for converting greenhouse gas and surplus benzene into value-added toluene and xylene. Herein, a bifunctional catalyst comprising Zn/Ga oxides and HZSM-5 zeolite was developed to efficiently promote the methylation of benzene with CO 2 and H 2 . This catalytic system exhibited excellent performance at 425 ℃ and 3.0 MPa, through which benzene conversion of 39.1% and total xylene/toluene selectivity of 92.7% have been achieved. Furthermore, the catalysts are carefully characterized; compositions of Zn/Ga oxides and Si/Al ratios of HZSM-5 zeolite are recognized as decisive factors for reaction activity and selectivity respectively. Additionally, primary reaction pathways are explored and testified to provide detailed understanding for the establishment of reaction networks, especially for mechanisms of ethylbenzene evolution. These findings are able to provide more deep insights into the process of benzene alkylation, which further facilitates the emergence of effective catalysts with potential industrial applications.
研究领域:
催化化学
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环境科学
✓ 已验证
DOI
高影响因子
PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
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2025
·
IF 7.8
Zhentao Wang,Jian Zhang,Shanshan Guo,Yufei Cai,Ling Ma,Yuting Huang,Shucheng Wu,Weibing Wu,Weirong Zhao
Biomass catalytic pyrolysis for the production of aromatics as an alternative to petrochemical resources is a promising technology in the context of carbon neutrality. The aromatization of furans presents a novel pathway for converting biomass into aromatics. In this study, four binary molten chlorides (NaCl-FeCl 2 , NaCl-MnCl 2 , NaCl-ZnCl 2 , and NaCl-MgCl 2 ) were selected for the pyrolysis of pine sawdust. The thermal stability and eutectic points of the binary molten chlorides were tested by TG-DSC. The introduction of binary molten chlorides significantly increased the selectivity for furans in bio-oil, reaching 72.2–91.8 area% for NaCl-ZnCl 2 and 42.8–71.2 area% for NaCl-FeCl 2 . Commercial HZSM-5 was characterized by SEM, XRD, BET, NH 3 -TPD, and Py-IR, and HZSM-5/cordierite monolithic catalysts were prepared. Co-pyrolysis of pine sawdust and polypropylene in binary molten chlorides were conducted, combined with in-situ or ex-situ catalytic processes. Furans generated from the pyrolysis of pine sawdust in binary molten chlorides served as key intermediates for the production of aromatics with high selectivity in a single step. In ex-situ catalytic pyrolysis, the highest selectivity for aromatics reached 91.2 area%. The van Krevelen diagram indicated that the aromatics from bio-oil had the potential to substitute ethylene tar in carbon black production. Diels–Alder reactions were discussed in the proposed reaction pathways for catalytic co-pyrolysis.
研究领域:
能源与环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2025
·
IF 8
Juhao Wu,Hong Tian,Fan Gu,Hai Ning,Junjie Huang,Binbin Chen,Yanlin Zeng,Huimin Mao,Xinmiao Wang
Pyrolysis technique can effectively convert waste plastics into high-performance asphalt modifiers, improving the asphalt pavement performance, thus achieving the resourceful utilization of waste plastics as building materials. Selecting Polypropylene (PP) and polystyrene (PS) as raw materials, pyrolysis experiments were conducted to explore their synergistic interaction. Using Thermogravimetric analysis (TGA), tube furnace, and gas chromatography-mass spectrometry (GCMS), the effects of plastics mixing ratio and Ni loading in HZSM-5 on the pyrolysis products and heavy oil composition were investigated. Based on the optimal heavy oil, the high and low temperature performance and aging resistance of the heavy oil modified asphalt were quantitatively evaluated. The results showed that the PP/PS co-pyrolysis exhibited higher conversion efficiency, with a 1:3 ratio maximizing liquid yield at 74.26 %. Ni-modified HZSM-5 effectively boosted the production of aromatic hydrocarbons in heavy oil while inhibiting the generation of phenols, acids, organosilicons and other non-hydrocarbon byproducts. The optimal Ni loading was 10 wt%, which maximized aromatic hydrocarbon content at 81.36 % within 90.6 % polycyclic aromatic hydrocarbons (PAHs), achieving the best modulation of pyrolysis heavy oil components. The addition of heavy oil significantly improved the high-temperature stability and aging resistance of asphalt, though impairing low-temperature cracking resistance. The optimal oil content was 6 wt%, making the softening point increased by 10.3°C. This advancement promoted the conversion of waste plastic heavy oil into high-performance asphalt modifiers to avoid difficult combustion, providing theoretical support and technical guidance for its high-value application in the asphalt pavement field.
研究领域:
材料科学
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环境工程
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化学工程
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道路工程
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资源循环利用
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催化化学
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高分子材料
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建筑材料
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
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2024
·
IF 9
Xiaohua Li,Junlong Wang,Yongbo Yu,Yu Cao,Shanshan Shao,Shiliang Wu
Inexpensive catalyst sources are of great importance in the conversion of biomass to economically valuable monocyclic aromatic hydrocarbons , and transition metals (Co, Ni, Fe and Mn) rich in catalytic effects in massive waste lithium battery cathode materials are not effectively reutilized currently. For this reason, the feasibility of employing the valuable metal oxides in the carbon-reduced waste lithium battery cathode materials (waste LiFePO 4 batteries, LFP, and waste LiNi x Co y Mn 1–x–y O 2 batteries, NCM) with HZSM-5 as coupled catalysts in the rape straw catalytic pyrolysis to produce aromatic hydrocarbons was explored. The carbon-reduced waste lithium battery cathode materials performed well at 5 wt% carbon loading, and the content of active components Fe 2 O 3 (SLFPC-5) and NiO (SNCMC-5) used for the reduction of large molecular oxygenates in biomass pyrolysis gas was increased by water leaching treatment. SLFPC-5 demonstrated superior bond-cutting performance, while SNCMC-5 exhibited strong deoxygenation performance. The selectivity of monocyclic aromatic hydrocarbons (MAHs) catalyzed by SLFPC-5/HZSM-5 and SNCMC-5/HZSM-5 was as high as 63.69 % and 79.19 %, with BTX yields of 14.58 wt% and 16.68 wt% respectively. This coupled catalytic system offers a low-cost source of catalysts for biomass catalytic pyrolysis and broadens the possibility of high-value recycling of wasted lithium batteries.
研究领域:
能源与环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Qian Yao,Ying Zhang,Yao Fu
We report on catalytic fast pyrolysis microalgae under ammonia atmosphere into acetonitrile over Ga/HZSM-5, which provides a long-term sustainable option for acetonitrile production and microalgae valorization. The effect of various catalysts, reaction conditions and species of microalgae on acetonitrile production was explored systematically. Under the optimized conditions, the maximum carbon yield of acetonitrile from Chlorella vulgaris was 23.4%, and the selectivity of acetonitrile in bio-oil was up to 77.2%. The possible reaction pathways were proposed according to the comprehensive experimental investigation on the conversion of model compounds and intermediates (proteins, carbohydrates, lipids, amino acids, carboxylic acids, furans, and amines). High-resolution transmission electron microscopy (TEM) analysis showed that Ga was present mainly at the outer surface of zeolite crystals, and a small amount of Ga was doped into the zeolite crystals.
研究领域:
化学工程
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环境科学
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材料科学
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生物化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Ming Huang,Liang Zhu,Wenbiao Zhang,Lingjun Zhu,Zhongqing Ma,Dengyu Chen
Co-feeding of waste plastics during biomass catalytic fast pyrolysis can improve remarkably the yield of aromatic hydrocarbons. In this work, the simulated biomass by using its model components of cellulose, xylan, and lignin at different proportions was Co-CFP with LDPE to investigate the synergistic reaction mechanism between biomass and low-density polyethylene (LDPE) over hierarchical HZSM-5. Results showed that biomass and its model components were oxygen-enriched feedstock, while LDPE was the hydrogen-enriched feedstock with H/C eff over 2. The synergistic effect between biomass model components and LDPE was ordered as cellulose and LDPE > xylan and LDPE > lignin and LDPE. Because pyrolysis of cellulose produced higher yield of furans than that of xylan and lignin which acted as the key synergistic compounds in Diels-Alder reaction to form light aromatics. The transfer of hydrogen free radical from the LDPE-derived hydrocarbons to the biomass-derived oxygenates promoted the deoxygenation reaction of oxygenates in hierarchical HZSM-5. Diels-Alder reaction between furans and olefins was the key synergistic reaction which highly improved the yield of hydrocarbon aromatics. In general, the difference of the pyrolysis oxygenated intermediate among the biomass pseudo components resulted in different yields of light aromatics, where cellulose presented highest extent of synergistic reaction to LDPE.
研究领域:
能源化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）