INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
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IF 4.939
Liying Zeng,Yizhou Wang,Jun Mou,Fei Liu,Chunliang Yang,Tianxiang Zhao,Xiaodan Wang,Jianxin Cao
γ-Al 2 O 3 was composited with ZSM-5 molecular sieve to improve its catalytic performance and hydrothermal stability during the conversion of crude methanol into dimethyl ether (DME). When prepared by a liquid-phase coating chemical compounding, the ZSM-5/γ-Al 2 O 3 composite catalyst reached an excellent methanol conversion of 91.9% and DME selectivity of 100%. The DME yield was increased by about 13% compared to only using γ-Al 2 O 3 . Partial desiliconization and dealumination of the ZSM-5 molecular sieve effectively reduced the surface acid center strength and increased the mesoporous ratio. The special composite phase interface effectively decreased surface charge density of γ-Al 2 O 3 and formed the B (Brønsted) - L (Lewis) synergistic active centers. All these factors contribute to improving the catalytic performance, hydrothermal stability and resistance to deactivation of ZSM-5/γ-Al 2 O 3 during the conversion of crude methanol to DME.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2019
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IF 3.375
Siqian Zhang,Cheng Zhang,Qiang Wang,Wha-Seung Ahn
A series of ZSM-5 catalysts were synthesized using fly ash from power plants and red mud from aluminum production in different weight ratios. The ZSM-5 was subsequently coimpregnated with Co and Mn and tested for the low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR). These catalysts were characterized by XRD, N2-adsorption isotherms, SEM, XPS, and H2-TPR. Among all the prepared catalysts, 5 wt % Co 10 wt % Mn/ZSM-5 had shown the best catalytic activity, with 98.8% conversion of NOx and 90.7% selectivity toward N2 at 150 °C. This is comparable to the performance of a similar ZSM-5 catalyst prepared using chemical reagents. The high ratio of Mn4+/(Mn4+ + Mn3+ + Mn2+) in the catalyst improved the NOx conversion, whereas the moderate redox property imparted by Co3+ led to high N2 selectivity. This catalyst also showed strong resistance against poisoning in 100 ppm SO2 and 5% H2O. This work demonstrates that effective NOx removal treatment with high N2 selectivity and sufficient stability for either cement plants or incinerators can be achieved by using a porous catalyst/support material produced from industrial solid wastes.
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CHEMICAL ENGINEERING SCIENCE
·
2026
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IF 5.1
Shuang Liu,Lei Ye,Shaokai Huang,Peng Zhou,Mingxuan Ma,Miao Hu,Xujin Ren,Xin Pu,Xin Han,Jichang Liu
La/ZSM-5@ASA composites were developed by a stepwise assembly strategy. • La 3+ displaced the acidic protons and generated new BAS [Si-OLa(OH) 2 -Al]. • ASA overcoat passivated external surface acid sites and enabled pre-cracking. • Hierarchical La/ZSM-5@ASA shows high light-olefin selectivity in n -paraffin cracking. Catalytic cracking of surplus automotive fuels, heavy oil and waste plastics into light olefins is an efficient resource-reutilization strategy. Conventional ZSM-5 zeolites, however, suffer from limited light-olefin selectivity and coke-induced deactivation due to strong acidity and microporous constraints. Herein, a stepwise assembly strategy involving La modification and subsequent amorphous silica-alumina (ASA) overcoating was developed to construct core–shell catalysts with optimized acidity and diffusion. La modification modulated acid strength and distribution, and DFT calculations revealed it lowered the energy barrier of the rate-determining protonation step, promoting propylene formation. The ASA overcoat, applied via co-gelation, passivated external strong Brønsted acid sites and introduced open interfacial diffusion channels. This architecture enabled pre-cracking of reactants, promoting efficient C-C bond cleavage and suppressing secondary reactions. The optimized hierarchical La/ZSM-5@ASA(1:1) achieved 63.10% total ethylene and propylene selectivity in n -heptane cracking, outperforming ZSM-5 and 0.50La/ZSM-5 by 5.12% and 1.38%, respectively. This advantage is more pronounced for longer linear hydrocarbons, and the suppression of methane and coke precursors boosts atom utilization efficiency, indicating a carbon-economic cracking pathway.
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Journal of Environmental Chemical Engineering
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2023
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IF 7.7
Ruokun Jia,Jiayuan Deng,Xiaohang Yang,Ruisong Xue,Pengpeng Wang,Xingbo Bian,Qiyao Wang
Graphitic carbon nitride (CN) hold great promise as a photocatalyst for generating hydrogen energy via water splitting, owing to its remarkable ability to respond to visible light and its strong reduction capacity. However, the photocatalytic water splitting for H 2 evolution performance of pure CN was impeded by its low surface area, inadequate hydrophilicity, and unsatisfactory photoelectric conversion efficiency. Here we tackled these challenges by synthesizing a series of CN/H-ZSM-5 composites with varying amount of H-ZSM-5 zeolite using a straightforward thermal copolymerization method. The contact angle and N 2 adsorption-desorption measurements confirmed that the incorporated hydrophilic and porous H-ZSM-5 zeolite contribute to increased surface area and improved hydrophilicity of the CN/H-ZSM-5 composites. Meanwhile the resulting CN/H-ZSM-5 composites exhibited significant separation and migration enhancement of photoexcited charge carriers. Consequently, the optimized CN/H-ZSM-5 composite, containing 50 mg of H-ZSM-5 zeolite, demonstrated 13 times increase in photocatalytic H 2 production rate than that of pure CN. This work not only provided a competitively universal approach on the design of high-efficiency CN based photocatalyst, but also clarified the role of H-ZSM-5 zeolite in the H 2 evolution enhancement.
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ENERGY & FUELS
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2023
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IF 5.3
Haifeng Tian,Zhiyu Chen,Xing Yang,Peng Gao,Chunxue Jiao,Fei Zha,Yue Chang,Hongshan Chen
A method for the direct synthesis of hierarchical zeolites was developed by converting precursors of zeolites and mesoporous copolymers into homogeneous gels using conventional block copolymers as scaffolds. In this method, hydrothermal synthesis is accomplished on a steam-assisted basis, and the dry gel leaves the system free of the liquid water phase, which successfully avoids phase separation between the soft stencil and the solid silica phase. The catalytic performance of hierarchical zeolites was evaluated on a fixed-bed reactor for the methanol-to-aromatics reaction. The hierarchical structure greatly enhances the catalytic activity of the probe reaction due to the increased outer surface, decreased coke formation, and diffusion resistance in the microporous network. The selectivity of BTX reached 65.8%, and there was no significant deactivation after a reaction of 107 h. The transition state and energy barrier for methanol to aromatics were obtained by the minimum energy search of the LST/QST transition state.
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高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2023
·Vol. 30
·期 32
·78988-79000
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IF 5.8
Dong Jiayu,Song Xianni,Zhang Shuchi,Tan Mengyu,Zhao Haiyan,Wu Donglei
A novel hierarchical Cu/ZSM-5 was prepared over alkaline treatment and incipient wet impregnation method for the catalytic ozonation of polyvinyl alcohol (PVA). Under the optimum preparation conditions, hierarchical Cu/ZSM-5 exhibited an excellent mineralization performance during the PVA degradation process, and the removal rate of TOC after 60 min of reaction was 47.86%, much higher than that of ozonation alone (5.40%). Its high catalytic activity could attribute to the large pore volume (0.27 cm 3 /g) and pore size (6.51 nm) which are beneficial for the distribution of loaded copper and adsorption performance for PVA. Compared to ·OH, 1 O 2 (2.66 times in 10 min) contributed more to the removal of PVA. The degradation of PVA was a combined process of direct ozone oxidation, catalytic ozonation and adsorption. With its high catalytic performance and stability, hierarchical Cu/ZSM-5 has a very broad application prospect in the process of catalytic ozonation of refractory pollutants.
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PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
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2019
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IF 4.63
Tingting Zhao,Fuwei Li,Hongchang Yu,Shilei Ding,Zhixia Li,Xinyuan Huang,Xiang Li,Xiaohan Wei,Zhenlin Wang,Hongfei Lin
Conversion of biomass-derived chemicals into light olefins is a promising method to maintain sustainable development of light olefin industry. In this study, three mesoporous ZSM-5 zeolites (MZSM-5-A, MZSM-5-B and MZSM-5-C) with major pore diameter about 4.8 nm, 16 nm and 22 nm were synthesized using a hydrothermal method by utilizing different templates. The catalytic activity of catalysts was studied by catalytic cracking of ethanol and oleic acid. The influence of reaction temperature on conversion and product selectivity was investigated. The characterization of ZSM-5 samples showed that the orders of the external surface area and mesopore volume were MZSM-5-C > MZSM-5-B > MZSM-5-A > conventional HZSM-5. In ethanol to light olefin reaction, MZSM-5-C achieved the highest light olefin yield (318.3 mL g −1 ) and ethylene selectivity (42.3%) at 400 °C. In oleic acid to light olefin reaction, MZSM-5-B achieved a complete conversion of oleic acid at 500 °C, and obtained the highest light olefin selectivity (38.1%) at 550 °C. The difference may be relevant to the size and chemical structure of feedstock molecular as well as the acidity of catalysts. Regardless of ethanol or oleic acid as feedstock, introduction of mesopore in zeolites significantly enhanced the light olefin yield and selectivity.
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BIORESOURCE TECHNOLOGY
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2018
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IF 5.807
Leilei Dai,Yunpu Wang,Yuhuan Liu,Roger Ruan,Dengle Duan,Yunfeng Zhao,Zhenting Yu,Lin Jiang
Catalytic fast pyrolysis (CFP) of torrefied corn cob using Ni-modified hierarchical ZSM-5 catalyst was conducted in this study. The prepared catalysts were characterized by N 2 adsorption and desorption (N 2 -BET), X-ray diffraction (XRD), and temperature-programmed desorption of NH 3 (NH 3 -TPD). NaOH solution treatment resulted in the lower peak intensities of hierarchical ZSM-5 catalyst in the XRD patterns while Ni modification improved the catalyst framework. In addition, NaOH solution treatment created some mesopores or macropores, but the incorporation of Ni reduced BET surface area and volume of micropores. Though the addition of Ni lowered the acidity of catalyst, Ni-modified hierarchical ZSM-5 catalyst led to higher yields and of aromatic hydrocarbons. What is more, hierarchical ZSM-5 catalysts significantly improved the selectivities of mono-aromatics. Kinetic analysis shows that CFP of torrefied corn cob was second-order reaction and the addition of Ni can obtain a lower activation energy compared with hierarchical ZSM-5 catalyst.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Zhen Zhang,Jiang Wu,Bin Li,Huibin Xu,Dongjing Liu
Zeolite (ZSM-5), as a kind of carbon-free sorbent or catalyst, has been widely applied in many fields due to its big surface area, good chemical and thermal stability, and excellent adsorption performance. In this study, Mn-Fe modified ZSM-5 are synthesized via sol-gel approach and employed for elemental mercury (Hg 0 ) removal from simulated flue gas at low temperature. The results show that pure ZSM-5 shows poor mercury capture ability with Hg 0 removal efficiency of ~8.5–18.8% at 100–300 °C. Mn or Fe modification can both efficiently enhance the Hg 0 removal efficiency of the ZSM-5. The sorbent with Mn/Fe molar ratio of 1:2 exhibits the optimal mercury capture ability with the highest Hg 0 removal efficiency near 100% at temperatures of 200 and 250 °C due to the significant synergy effect between Mn 2 O 3 and Fe 2 O 3 . The presence of NO has a negligible effect on the Hg 0 removal performance of Mn/ZSM-5 and Mn1Fe2/ZSM-5, while the existence of SO 2 considerably degrades the Hg 0 capture performance of Mn/ZSM-5 owing to competing adsorption and side reactions. Fe addition can protect Mn active sites from SO 2 poisoning and thereby enhancing the SO 2 resistance of Mn/ZSM-5 to some extent.
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高影响因子
CATALYSIS COMMUNICATIONS
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2018
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IF 3.463
Qinqin Wang,Mingyuan Zhu,Haiyang Zhang,Caixia Xu,Bin Dai,Jinli Zhang
Zr-modified ZSM-5 zeolite was successfully prepared, and Zn/Zr-ZSM-5 was employed as a catalyst for the acetylene hydration reaction. High catalytic activity, above 96% C 2 H 2 conversion, was achieved at 260 °C with a feed reactant ratio of H 2 O/C 2 H 4 = 4 and a GHSV of 90 h −1 . To understand the influence of zirconium addition in the zeolite, Fourier-transform infrared spectroscopy, X-ray diffraction, surface texture analysis (BET method), transmission electron microscopy, temperature programmed desorption of NH 3 , temperature programmed reduction by hydrogen and X-ray photoelectron spectroscopy techniques were used. The incorporation of zirconium in the zeolite enhanced Zn metal dispersion and metal–support interactions. Moreover, an enhanced concentration of weak acid sites and active catalytic sites were found to be responsible for the high catalytic activity of Zn/Zr-ZSM-5 for the acetylene hydration.
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JOURNAL OF CATALYSIS
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2017
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IF 6.844
Qiguang Dai,Qin Zhu,Yang Lou,Xingyi Wang
ZSM-5 zeolites (NaZSM-5, HZSM-5 and Silicalite-1) with different acid nature were synthesized and used as supports of Pd catalysts for catalytic combustion of methane. Moreover, the acid property of the as-synthesized Pd/NaZSM-5 catalyst was adjusted by a NH 4 + ion-exchange process to post-generate Brønsted acid sites and different preparation methods were investigated. The potential roles of Brønsted acid sites (anchoring Pd species or activating methane molecules) were discussed, and the experimental results indicated that the anchoring effect of Brønsted acid sites on Pd species was not directly observed. However, the acid properties of supports (the presence of Al 3+ as Lewis acid sites, especially coordinatively unsaturated Al 3+ ) were crucial for the preparation of Pd/ZSM-5 catalysts with high Pd dispersion. Additionally, although Brønsted acid sites of ZSM-5 was contributed to the activation or even cracking of long-chain alkanes (such as n -decane), the direct adsorption/dissociation of methane on Brønsted acid sites was difficult and depended more on the dispersion and particle size of PdO x . Pd/NaZSM-5 catalyst presented an outstanding durability at low-temperature (350 °C) and high-temperature (800 °C), and the high Si/Al ratio could improve the water-resistance due to its good hydrophobicity, but the reversible deactivation owing to the formation of PdO into Pd(OH) 2 under high concentration of water vapor was still unavoidable.
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JOURNAL OF MEMBRANE SCIENCE
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2025
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IF 9
Jia Ding,Yuanhao Wu,Shurong Wu,Shengyu Zhou,Yulong Li,Chao Fan,Hanxiao Liu,Penghui Ren,Shengwei Deng,Jianguo Wang
The direct carbonylation of glycerol with CO 2 is an alternative route to produce high-valued glycerol carbonate, which however faces challenges like low catalytic conversion due to the thermodynamic equilibrium limitation. In this work, ZSM-5 membranes with different Si/Al molar ratios were prepared by hydrothermal method, and coupled with Ce–La–Co mixed metal oxide (CeLaCo-MMO) catalysts for enhancing the glycerol carbonylation performance by in situ water separation. The Si/Al ratio of ZSM-5 showed significant influences on the water permeance, separation selectivity, and catalytic performance for glycerol carbonylation, due to the precise concentration control of Na + gated water transport channels. The reaction-separation coupling process achieved a glycerol conversion of 40.1 %, which was about 4.5 times higher than the conventional batch reactor. The as-synthesized ZSM-5 membrane also exhibited good reusability performance in the cycling test. This work provides a new in-situ water separation strategy for boosting glycerol carbonylation performance without consuming chemical or physical dehydrating agents as compared to the investigations in the literature.
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