Journal of CO2 Utilization
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2022
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IF 8.321
Yutong Shen,Jun Xiao,Qijing Wu,Jingting Su,Li Zhu
To improve the conversion efficiency and reduce the CO 2 emissions associated with the reforming of biomass tar to syngas, photothermal catalysts were prepared in this study through various impregnation methods. Photothermocatalytic CO 2 reforming (PTCR) of benzene as a tar model compound, was conducted using the prepared Ni/TiO 2 -Al 2 O 3 catalysts. The results show that the introduction of TiO 2 facilitates the conversion of NiO to Ni during the photothermal reaction, while the photocatalysis of TiO 2 significantly enhances the photothermocatalytic activity of the Ni/Al 2 O 3 catalysts at low temperatures. Moreover, the methodology for catalyst preparation involving the loading of NiO before TiO 2 is also beneficial to catalyst performance. However, when the mass ratio of TiO 2 to Al 2 O 3 exceeds 1, the specific surface area, pore volume, and structural stability of the catalysts are reduced. The results of PTCR experiment show the following optimal Ni/TiO 2 -Al 2 O 3 catalyst preparation parameters: 25% NiO content and a TiO 2 /Al 2 O 3 ratio of 3:7; 450 °C calcination temperature and a nitrogen atmosphere. The maximum benzene conversion achieved through PTCR with the 0.25Ni/0.3Ti0.7Al(M2) catalyst is 88.2%. However, a large amount of coke is deposited onto the spent catalyst surface, contributing significantly to catalyst deactivation.
研究领域:
能源化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE ENERGY INSTITUTE
·
2023
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IF 5.7
Saisai Liu,Jing Liu,Guanyi Chen,Jingang Yao,Beibei Yan,Weiming Yi,Chunyan Tian,Huijie Zao
Herein, spherical and nanosheet-like SAPO-11s were successfully synthesized hydrothermally and utilized to catalyze the methanol-to-gasoline (MTG) process. The nanosheet-like SAPO-11 (SAPO-11-A) had a thickness of about 10 nm, while the spherical SAPO-11 (SAPO-11-B) had a particle size of around 11 μm. Compared to SAPO-11-B, the property of SAPO-11-A was enhanced by 42.9% in specific surface area (SSA), 38.1% in mesopore volume (V me ) and 20.2% in acid amounts, respectively. In terms of catalytic performance during the MTG reaction, SAPO-11-A demonstrated superior results not only in the methanol conversion (95.82%), gasoline-range hydrocarbons selectivity (58.76%) and iso/nparaffin ratio (8.17) but also in suppressed coke deposition (2.56%) compared with those (90.63%, 50.95%, 4.75 and 5.73%, respectively) of SAPO-11-B. Additionally, the optimal MTG process conditions were identified utilizing SAPO-11-A, demonstrating a methanol conversion rate of 98.34%, a gasoline hydrocarbon selectivity of 67.61%, an isoparaffin selectivity of 36.01% and an iso/nparaffin ratio of 10.94 at 380 °C, weight hourly space velocity (WHSV) of 2 h −1 and 1 MPa. These results highlight the potential of nanosheet SAPO-11 to produce gasoline-range hydrocarbons rich in isoparaffins.
研究领域:
催化化学
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能源材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Yaning Wang,Xiaohang Sun,Xiaohan Yu,Rongjun Zhang,Binhang Yan
Effects of A-site cation substitution and B-site active metal doping-segregation on physicochemical properties of Ni-doped perovskite-structured LnFe 0.7 Ni 0.3 O 3 (Ln = La, Nd, Sm, Eu) catalysts and their catalytic performance for dry reforming of ethane (DRE) were studied. The DRE activity follows the trend: NdFe 0.7 Ni 0.3 O 3 > SmFe 0.7 Ni 0.3 O 3 > EuFe 0.7 Ni 0.3 O 3 > LaFe 0.7 Ni 0.3 O 3 . The doping-segregation process of Ni was demonstrated by in-situ X-ray Diffraction (XRD) and X-ray Absorption Fine Structure (XAFS) measurements, which significantly improves the dispersion of Ni and enhance the interaction between metal and support. The results of temperature-programmed surface reactions (TPSR) and pulse reactions indicate that oxygen vacancies generated by the exsolution of Ni play an important role in the elimination of coke and shift the product from surface carbon to gaseous CO. According to the in-situ Raman experiments, the superior catalytic stability (no coke deposition or activity loss over 100 h) of NdFe 0.7 Ni 0.3 O 3 is ascribed to its strong resistance towards carbon deposition.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2024
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IF 11.3
Jie Fan,Wen-Cui Li,Lei He,Bowen He,Fan Tang,Zhankai Liu,Dongqi Wang,Xi Liu,Liwei Chen,An-Hui Lu
Ni-based catalysts are the most promising candidates for methane dry reforming (MDR) reaction but still suffer from deactivation caused by coke-deposition. Herein, we reported a coke resistance MDR catalyst consisting of cationic Ni clusters (Niδ+, 0 < δ < 2) stabilized over oxygen-functionalized boron nitride. A simple method was developed for the fabrication of highly dispersed cationic Ni clusters on boron nitride. The local coordination modes between nickel and boron nitride determine the formation of cationic Ni clusters. We provided detailed spectroscopy and microscopy characterizations to reveal the structure features of these cationic Ni clusters. The average particle size of these clusters is ∼1.7 nm. There are abundant Nixδ+–O–B interfaces on the cationic Ni clusters, which serve as catalytically active sites. Compared to conventional metallic Ni nanoparticles, the cationic Ni clusters exhibited comparable apparent catalytic activity and reduced carbon deposition, particularly operated at 600 °C where unavoidable coke formation from CH4 cracking and the Boudouard reaction usually tends to occur thermodynamically and kinetically. Based on theoretical and experimental evidence, a dynamic synergistic conversion mechanism for CH4 and CO2 on the Nixδ+–O–B interface has been revealed. The oxygen within the Nixδ+–O–B interface could rapidly convert CHx*(x = 1–3) intermediates forming H2 and CO to avoid carbon deposition. CO2 is efficiently activated at boron sites of the Niδ+–O–B interface to regenerate active oxygen species, thereby boosting the conversion of CH4. These insights may shine light on the development of intrinsic coke-free Ni-based catalysts for methane dry reforming in the near future.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2018
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IF 4.908
Qicong Liu,Zhe Xiong,Syed Shatir A. Syed-Hassan,Zengtong Deng,Xingyu Zhao,Sheng Su,Jun Xiang,Yi Wang,Song Hu
Ni-based catalyst is prone to the deactivation by coke deposition during the catalytic steam reforming of bio-oil. In order to optimize catalytic activity of the Ni-based catalyst, a two-stage catalytic reforming scheme was proposed whereby a low-temperature (350–600 °C) pre-reforming process with a less expensive catalyst was introduced prior to the Ni-based catalyst. To study this scheme, the reforming experiments with different combinations of Fe/bio-char (in the first stage) and Ni-Ca/γ-Al 2 O 3 (in the second stage) were conducted. In addition to the quantification of product yields, the tar and gas were characterized with an ultraviolet (UV) fluorescence spectroscopy, a gas chromatography/mass spectrometer (GC/MS) and a gas chromatography (GC). The results indicate that significant proportions of naphthalenes and polycyclic aromatics in the intermediate volatiles turned into furans, phenols and non-aromatics, which are easier to be reformed on Ni-based catalysts, via the Fe/bio-char pre-reforming, resulting in the increase of the final H 2 and CO yields of the overall process. At high pre-reforming temperatures (550–600 °C), the coke formation on Ni-based catalyst was significantly inhibited due to the Fe/bio-char pre-reforming. In addition, the results indicate that the spent Ni-based catalyst had more free NiO and NiAl 2 O 4 spinel than the fresh one, suggesting that the increase in the catalytic activity of Ni-based catalyst during the reforming process was promoted by Fe/bio-char pre-reforming.
研究领域:
能源科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Mingjie Liao,Xin Ning,Junwen Chen,Jiajun Zheng,Wenlin Li,Ruifeng Li
Zeolite is one kind of the solid acid catalysts for the oligomerization process but surfers from rapid deactivation. In this specific study, a series of mesoporous ZSM-5 catalysts have been synthesized and evaluated in the 1-hexene oligomerization. XRD, BET, SEM, TEM, 27 Al MAS NMR, 29 Si MAS NMR, NH 3 -TPD, Py-FTIR and TGA analysis were used to characterize the physicochemical properties of zeolites. The synthesized mesoporous zeolites were found to be more stable in the reaction and the initial activity increase significantly compared with the common ZSM-5 zeolite . Moreover, the catalytic activity of mesoporous ZSM-5 zeolite is found to be closely related to the number and the distribution of acid sites. The mesoporous ZSM-5 zeolites with the lower amount of acid sites, moderate strength of Brønsted acid sites inhibiting the cracking and coke products. High L/B ratio enhanced the dimers formation. The efficiency was further highlighted by a high space–time yield (STY) of 557 mg·g cat −1 h −1 in the average stage at 260 °C. Compared to conventional ZSM-5 catalyst, the synthesized catalyst displayed excellent resistance to coke deposit.
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
RSC Advances
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2020
·Vol. 10
·期 50
·29618-29626
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IF 3.119
Yanming Jia,Qinghua Shi,Junwen Wang,Chuanmin Ding,Kan Zhang
Hierarchical nano-ZSM-5 zeolites (Z5-X) with different grain sizes were synthesized by varying amounts of 3-glycidoxypropyltrimethoxysilane (KH-560) in the hydrothermal synthesis strategy. Moreover, the conventional ZSM-5zeolite(Z5), which was prepared without KH-560, was used as the reference sample. The crystalline phases, morphologies, porous characteristics, Si/Al molar ratios and acidic properties of all fresh catalysts were characterized using the X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), N2 adsorption–desorption, inductively coupled plasma atomic emission spectroscopy (ICP) and temperature programmed desorption of ammonia (NH3-TPD) techniques. Results show that the grain size and strong acid amount of zeolite decreased with the increasing amount of KH-560. The micropore surface areas and the corresponding volume of Z5-X changed less compared with Z5. Consequently, the high shape-selectivity of zeolite was preserved well under the addition of KH-560. However, the mesopore surface areas and the corresponding volume increased significantly with the increasing amount of KH-560. Benefiting from the abundant hierarchical structure, the Z5-X catalysts exhibited a larger coke capacity than the Z5 catalyst. The coke depositions of all the deactivated catalysts were characterized by the thermogravimetric technique (TG), and the results are indicative of the decreased average rate of coke deposition with an increasing amount of KH-560, which could result from the gradually reduced strong acid amount and the nano-sized crystallites. The catalytic performance of methanol-to-aromatics (MTA) indicates that the Z5-0.12 catalyst exhibited higher catalytic activity and selectivity of BTX as the reaction was prolonged, which could result from the synergistic effect among the proper strong acid amount, the smaller zeolite grain size, and the abundant hierarchical structure.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Xingxing Cui,Hongyang Lyu,Yongming Chai,Bin Liu,Dongfeng Zhao,Chenguang Liu
The strong acidity on the external surface of ZSM-5 is a primary factor resulting in the low BTX selectivity and catalyst deactivation during the olefin aromatization. In this study, a membrane-restricted Silicalite-1@ZSM-5 core–shell structured catalytic catalyst was designed and constructed for 1-hexene aromatization using a hydrothermal coating method. TEM and NMR results confirmed the complete coverage of Silicalite-1 on the surface of ZSM-5, with a shell thickness of 50 nm. The further reaction of the TIPB (1,3,5-triisopropylbenzene) molecular probe reactions demonstrated the passivation of the acid sites on ZSM-5 external surface. The inert shell layer passivated the acid sites on the external surface, thereby suppressing the isomerization of PX and the side-chain alkylation reaction of light aromatics. Compared to ZSM-5, the Silicalite-1@ZSM-5 catalyst exhibited a 37.15 % increase in BTX selectivity, a 58.65 % increase in PX selectivity, significantly reduced coke deposition, and demonstrated better stability. This strategy of in-situ epitaxial growth of inert shell layers holds significant promise for enhancing the selectivity of shape-selective catalysts and extending catalyst lifetime.
研究领域:
催化化学
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材料科学
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石油化工
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2023
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IF 13.1
Yanan Xing,Guiyue Bi,Xiaoli Pan,Qike Jiang,Yuanlong Tan,Yang Su,Leilei Kang,Bonan Li,Lin Li,Aiqin Wang,Jingyuan Ma,Xiaofeng Yang,Xiao Yan Liu,Tao Zhang
Pt-based catalysts are the typical industrial catalysts for propane dehydrogenation (PDH), which still suffer from insufficient long-term durability due to the structural instability and coke deposition. A commercial γ-Al 2 O 3 supported thermally robust sub-nanometer Pt 2 In 3 intermetallic catalyst with atomically ordered structure and rigorously separated Pt single atoms was fabricated, which showed outstanding robustness in 240 h long-term operation at 600 °C with the deactivation rate constant k d as low as 0.00078 h −1 , ranking among the lowest reported values. Based on various in situ characterizations and theoretical calculations, it was proved that the catalyst stability not only resulted from the separated Pt single-atom sites but also significantly affected by the distance of adjacent Pt atoms. An increasing distance to 3.25 Å in the Pt 2 In 3 could induce a weak π-adsorption configuration of propylene on Pt sites, which facilitated the desorption of propylene and restrained the side reactions like coking.
研究领域:
催化化学
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材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Jian Li,Liguo Jiao,Zhiyu Li,Beibei Yan,Guanyi Chen,Sarwaich Ahmed
Tar is one of the biggest obstacles for commercial application of biomass gasification. Microwave catalytic cracking shows potential for not only removal but also conversion of tar. However, the coke formation under microwave has not been investigated. In the present work, a microwave applicable catalyst, Ni-Ce@SiC, was prepared. The effects of temperature and inlet tar concentration on toluene and phenol conversions were investigated under both microwave and conventional heating conditions, and the influences on coking rate were also focused. Results showed that increasing temperature and reducing inlet tar concentration improved tar conversion. Inlet tar concentration and cracking of phenol typically caused more coke deposition. Based on the characterizations of the spent catalysts, the microwave could eliminate the coke deposition and alter the coke types. The mechanism of microwave on the coke suppression was revealed. This study provids an in-depth understanding of the coke formation during the microwave process, and also builds foundation for the design and operation of catalytic process.
研究领域:
能源科学
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化学工程
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2019
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IF 5.155
Xingye Chen,Meng Ge,Yanyong Li,Yatian Liu,Jiameng Wang,Lihong Zhang
A series of novel γ -Al 2 O 3 supported Pt In bimetallic catalysts were prepared by perovskite (PTO) lattice interstitial confined reduction and compared with industrial catalyst PtIn/ γ -Al 2 O 3 in the propane dehydrogenation to propene . The physics-chemistry properties of all catalysts and precursors were characterized by BET, NH 3 -TPD, TPR, XRD , TEM , STEM-EDS, XPS , TG and O 2 -TPO techniques. The results show that the metal ions of Pt 4+ and In 3+ confined in PTO lattice interstitial sites were more easily reduced than those confined in PTO lattice. The lattice interstitial confinement was beneficial for the formation of small and highly dispersed Pt In bimetallic species on the surface of γ -Al 2 O 3 supported PTO Nano islands. It is just the confinement of PTO lattice interstitial sites for appropriate In 3+ /In 0 ratio and weak Pt In interaction and the sharing Al O bond for anchoring PTO nanoparticles and weakening the surface acid sites result in the high activity and superior stability of PtIn/LaAlO 3 / γ -Al 2 O 3 in propane dehydrogenation. The initial propane conversion of PtIn/LaAlO 3 / γ -Al 2 O 3 was 47%, and can be maintained at 25% after 16 h, while its propene selectivity only decreased from 96% to 90%.
研究领域:
催化
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材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jinye Hu,Wenguang Zhou,Yunpu Wang,Haiwei Jiang,Jiabo Wu,Ting Luo,Mengjiao Wang,Weixin Wang,Qi Wang,Yuhang Hu,Liangliang Fan
HZSM-5 widely used for the catalytic pyrolysis of biomass exhibits the drawbacks of high diffusion resistance and large coke production. To effectively enhance the catalytic efficiency and alleviate the coke deposition, a novel promising catalyst, HZSM-5 coated activated carbon (HZSM-5@AC), was prepared for the first time for in-line upgrading the pyrolysis products of soybean straw. Various catalysts including HZSM-5, activated carbon, and the HZSM-5@AC catalysts with different HZSM-5 to activated carbon mass ratios were characterized. The results showed that the HZSM-5 was successfully coated on the surface of activated carbon and the addition of activated carbon introduced a mesoporous structure and more acidic sites to the catalyst. The catalytic performance on the biomass conversion showed that the catalyst with HZSM-5-to-activated carbon mass ratio of 18:5 (18HZSM-5@5AC) had the highest catalytic efficiency on the conversion of biomass into aromatics with a selectivity of 99.5%, including 75.68% of benzene, toluene, and xylenes (BTX) with a yield of 74.68 mg/g. Moreover, a possible pathway for HZSM-5@AC catalyzed biomass pyrolysis was proposed through analyzing the conversion of model compounds. The catalyst cycling experiments demonstrated the higher stability of HZSM-5@AC than the parent HZSM-5 and activated carbon. TG, FTIR, Raman and SEM showed that the spent HZSM-5@AC was hardly structurally changed with a low coke yield of 0.08%. However, the spent HZSM-5 was partly structurally deactivated by large aromatic ring systems with a coke yield of 3.74%. SEM results also showed that a large amount of polymerized material encapsulated the surface of the spent HZSM-5.
研究领域:
能源化学
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催化材料科学
✓ 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）