APPLIED CATALYSIS A-GENERAL
·
2014
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IF 3.674
Zhihua Chen,Yuefei Feng,Tianxia Tong,Aiwu Zeng
The liquid phase Friedel–Crafts acylation of thiophene with acetic anhydride over HBEA zeolites modified by hydrochloric, nitric, and acetic acid was investigated in a trickle bed reactor. The catalytic stability of the HBEA zeolite was doubled after treatment with the hydrochloric and nitric acids due to the increase of the ratio of Broensted to Lewis acid sites, the surface area, and the average pore diameter. The deactivated zeolites can be regenerated by calcination in a muffle furnace and the superior reusability of the zeolite HBEA was demonstrated after nine cycles. Moreover, the carbon deposit was proved to be one of the main reasons for the deactivation by using 13 C NMR MAS, 27 Al NMR MAS, and TGA.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2017
·Vol. 9
·期 19
·3646-3654
·
IF 4.803
Bin Zhang,Qifan Wu,Chao Zhang,Xinluona Su,Ruhui Shi,Weiwei Lin,Yan Li,Fengyu Zhao
Graphical Stability from the support : The excellent stability of a Ru/ZSM-5 catalyst for levulinic acid hydrogenation in water relies on the higher tetrahedral-coordinated Al content and preferable pore connectivity in well-crystallized ZSM-5 zeolite, which suppress Ru aggregation and leaching and the formation of carbonaceous residues in the acidic environment. A long-life topic in the field of heterogeneous catalysis has been to develop supported catalysts that are stable against the aggregation of active metal and carbon deposition. Herein, we report a highly stable Ru/ZSM-5 catalyst for the hydrogenation of levulinic acid in water, which can be recycled at least 10 times without apparent loss of activity (conv. >95 %, yield >85 %). The influences of types of Al species, structure of support, Ru sizes, Ru leaching, and carbon deposition, etc. on activity and stability were discussed in detail. It was confirmed that the tetrahedral-coordinated framework Al in ZSM-5 contributed to the favorable metal–support interaction, and thus suppressed the aggregation and leaching of ruthenium during recycling. Besides, the suitable pore volume and channel network connectivity successfully prevent from deposition of carbonaceous residues.
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
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Chenyang Zhao,Yujia Liu,Hongwei Zhu,Junjie Feng,Huiyun Jiang,Fei An,Yan Jin,Wei Xu,Zhe Yang,Bing Sun
The ability to selectively remove H 2 from the product has made palladium (Pd) membrane reactor a good choice for steam reforming reaction. However, carbonaceous deposited on the surface of Pd membrane during reaction hindered its industrial application. In order to protect Pd membrane from being poisoned by water and light alcohols, a TS-1/Pd composite membrane was prepared by a facile one-step hydrothermal method combined with silane coupling treatment. The zeolite layer acted as a protective armor by keeping poisonous species away from the Pd bulk, and the silanization process increased the hydrophobicity by reducing the hydroxyl density on the surface of TS-1/Pd composite membrane. After 100 h’s exposure in the steam reforming condition, the percentage of carbon content was only 0.95% for the TS-1/Pd membrane, compared with 13.20% for the pure Pd membrane. The H 2 permeability and H 2 /N 2 selectivity of the TS-1/Pd remained constant, while that for pure Pd membrane fell by 50% and 80%, respectively. The significantly improved resistance to carbon deposition provides possibility for the large-scale application of Pd membrane reactor in hydrogen production via steam reforming.
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
JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Tingting Bao,Hui zhou,Yi Zhang,Chenxu Guo,Wenming Guo,Hang Qin,Pengzhao Gao,Hanning Xiao,Weixiong Liu
Ni/CeO 2 catalysts ( n CeO2 : n Ni = 0, 1, 4, 7, 10) supported on SiC porous ceramics for ethanol steam reforming (ESR) were investigated with respect to hydrogen production performance and growth of carbon deposition. The oxygen released from CeO 2 enables the oxidation of CH x species to serve as carbon precursors, thus providing Ni/CeO 2 catalysts with stronger resistance to carbon deposition compared with Ni catalysts. The Ni/CeO 2 catalysts prepared by inverse microemulsion and impregnation methods exhibit regular semicircular spherical shape on SiC porous ceramics. Under 500 °C for 25 h of ESR reaction, the ethanol conversion rate over Ni/CeO 2 catalysts ( n CeO2 : n Ni = 7) is sustained up to 100% and H 2 selectivity is essentially kept at 74%. The by-product selectivity declines stepwise with increasing content of CeO 2 , which is attributed to the adsorption and oxidation of CO and of CH x species as CH 4 precursor from CeO 2 . The scanning electron microscopy (SEM) and transform electron microscopy (TEM) results reveal that further loading of CeO 2 on the surface of Ni catalysts can alleviate both migration and sintering of Ni particles. Furthermore, carbon deposition on Ni/CeO 2 catalysts preferentially outgrow filamentous rather than amorphous carbon , with a tendency for the latter to be more deactivated.
研究领域:
催化化学
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材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 16
·15267-15276
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IF 2.195
Zhang Qingji,Jing Jiangping,Chen Zhuoyuan,Sun Mengmeng,Li Jiarun,Li Yan,Xu Likun
g-C 3 N 4 is a promising material for the application in the area of photoelectrochemical cathodic protection. However, it suffers from limited light absorption and lower charge separation efficiency. In this work, a N defects and C deposition co-modified g-C 3 N 4 , C–g-C 3 N x , was prepared by NaOH-assisted sintering and ethanol-assisted hydrothermal treatment. The presence of N defects and C deposition was verified by the XRD, SEM and XPS tests. The N defects changed the band structure of g-C 3 N 4 by lowering down the conduction band position, therefore widening the light absorption range of g-C 3 N 4 . In addition, the N defects and C deposition co-modification promotes the charge transfer process of g-C 3 N 4 , leading to increased separation efficiency of the photogenerated charge carriers. Therefore, C–g-C 3 N x shows enhanced photoelectrochemical cathodic protection performance for the coupled 316L stainless steel. It can provide a photoinduced potential drop of 120 mV and a photoinduced current density of 9.1 μA cm −2 , which is three times that of pristine g-C 3 N 4 .
研究领域:
材料科学
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电化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2025
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IF 2.5
Qixin Yang,Jing Di,Yin Li,Mengxuan Zhai,Haoquan Liang,Zengkun Wang,Qiongqiong Kan,Yuanyu Tian,Yingyun Qiao,Ruiqin Yang,Xikun Gai
Biogas dry reforming (BDR) technique has drawn widespread attention as an essential route for the utilization of renewable energy sources. It can produce highly valuable syngas from CO2 and CH4 conversion. However, Ni catalysts are very sensitive to coke deposition and sintering when catalyzing this process. It was discovered that highly dispersed Ni catalysts and bimetallic Ni catalysts can avoid carbon deposition and improve BDR reactivity. In this work, highly homogenous dispersed NiCo bimetallic catalysts was prepared via ammonia cycling method. By applying a series of characterization techniques to the catalysts, it can be found that ammonia reflux condensation is conductive to improve the dispersion of NiCo species and to strengthen the interaction of the active components with the carriers within catalysts. Most importantly, the 8Ni2Co/NH3-SiO2 catalyst showed the great activity and carbon deposition resistance during the 6 h test compared to the 8Ni/SiO2 and 8Ni/NH3-SiO2 catalysts. The conversion of CH4 and CO2 was 45.43% and 90.42%, respectively. Importantly, the carbon deposition on 8Ni2Co/NH3-SiO2 was 0.23%, which was higher than that on 8Ni/SiO2 catalyst (6.11%) prepared by isovolumetric impregnation. Consequently, our work may give insight into the appropriate design of high-performance catalysts for the BDR reaction.
研究领域:
催化化学
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可再生能源
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of CO2 Utilization
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2024
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IF 7.2
Luqman Abdullahi Sani,Haolong Bai,Zifu Xu,Liangliang Fu,Yining Sun,Xiaorui Huang,He Gao,Xuejing Liu,Dingrong Bai,Zhanguo Zhang,Fabing Su,Jiao Liu,Guangwen Xu
Ni/Al 2 O 3 catalysts (noted as Ni/Al-350, Ni/Al-500, and Ni/Al-700, respectively) were synthesized by a facile solution combustion method but at different combustion temperatures (350 °C, 500 °C, and 700 °C, respectively). For comparison, Ni/Al 2 O 3 (noted as Ni/Al-100) was also prepared by the impregnation method and applied in the methanation reaction. The Ni/Al 2 O 3 synthesized at the combustion temperature of 350 °C showed better performance than the others at higher combustion temperatures, and the activity for CO 2 methanation followed an order of Ni/Al-350 > Ni/Al-500 > Ni/Al-700 > Ni/Al-100. The increase in the combustion temperature decreased active sites for the H 2 and CO 2 adsorption, which could be associated with the reduced Ni dispersion and basic sites, thus lowering its activity and increasing its carbon deposition rate.
研究领域:
催化化学
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2025
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IF 7.5
Rujiao Jiang,Baojun Yi,Zhengshuai Sun,Jiayi Yang,Feng Guo
The influence of metal species and their locations within carbon deposition on their activities is a valuable contribution to the theoretical foundation for the development of new high-activity anti-deposition catalysts. The study demonstrate that Ni-Ce and Ni-Fe catalysts exhibit superior activity and anti-carbon deposition properties in comparison to monometallic Ni-based catalysts. The placement of carbon nanotubes on Ni-Fe catalysts and Ni-Mg catalysts resulted in a significant loss of activity due to the coverage of nanotubes. The catalytic activity of each bimetallic Ni-based catalyst with metal post placement was found to be higher, with the post- Ce catalyst exhibiting the greatest activity at 90.11%. The metal dispersion was enhanced, which CeO 2 , MgO, and Fe 3 O 4 were observed to act as pro-dispersive and redox agents on the Ni-based catalysts. This paper proposes a mechanism to elucidate the impact of metal species and their position within the carbon deposition during toluene reforming. It also provides a theoretical foundation for the thermal conversion and sustainable development of biomass.
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
JOURNAL OF RARE EARTHS
·
2019
·
IF 2.846
Dingwen Kang,Jie Yu,Wenhui Ma,Min Zheng,Yunfei He,Pengfei Li
In this study, Cu/Ni-La 0.7 Sr 0.3 Cr 0.5 Mn 0.5 O 3– δ (LSCM) catalysts were synthesized via the citric acid-nitrate process (CNP) and chemical co-precipitation. The catalytic performance of Cu/Ni-LSCM catalysts on dry methane reforming was evaluated in a fixed-bed reactor at 550/650 °C and atmosphere pressure. Cu/Ni loading was investigated as an influencing factor, which led to 5 cases of samples according to the different Cu/Ni mass ratios. The catalysts were characterized by X-ray diffraction (XRD), field emission-scanning electron microscope (FE-SEM), Brunauer-Emmett-Teller (BET) measurement, X-ray photoelectron spectroscopy (XPS), hydrogen-based temperature-programmed reduction (H 2 -TPR) and thermos gravimetric analyzer (TGA). The results show that the methane conversion increases, the resistance against metal sintering increases and the carbon deposition drops after the copper is introduced. This optimum performance can be obtained under Case 3 (Cu:Ni:LSCM = 1:3:6 in mass ratio).
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
Catalysis Science & Technology
·
2022
·Vol. 12
·期 12
·3874-3885
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IF 6.177
Ling Zhang,Jikai Sun,Shuchao Jiang,Huijie He,Guoqing Ren,Dong Zhai,Rui Tu,Shengliang Zhai,Tie Yu
This work reported an efficient PdIr/activated carbon (PdIr/AC) catalyst and its application during direct ethane dehydrogenation (EDH) into ethane. The XRD and HADDF-STEM results revealed Pd/Ir nano-particles and atomically dispersed Pd2+ and Ir4+ species simultaneously. The activity tests demonstrated that Ir species showed higher C2H4 selectivity than Pd species and the co-presence of Pd/Ir could further improve the catalytic stability and inhibit carbon deposition over the bimetallic Pd/Ir catalyst. Nevertheless, raising the reaction temperature from 500 °C to 600 °C boosted coking including carbon nanotubes (CNTs) and carbon particles. XPS results of Pd7Ir2/AC-B after Ar or H2 pretreatment proved that the active sites are Pd2+/Ir4+ species. The simulation results exposed the reaction pathway over Ir4+/Pd2+ species, and ethane dehydrogenation was the rate-determining step over the PdIr/AC sample; meanwhile, the synergetic effect between Pd2+ and Ir4+ increased their TOF (C2H4). Finally, a deactivation mechanism was also proposed to examine the coking over various metal species.
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
FUEL
·
2023
·
IF 7.4
Haoyue Fu,Weixin Qian,Haitao Zhang,Hongfang Ma,Weiyong Ying
Unmodified Cr/Al 2 O 3 and Cr/Al 2 O 3 doping with different alkali metals (Li, Na, K) were prepared by the incipient wetness impregnation method. The surface elements of all the catalysts are evenly distributed and well loaded, and the addition of alkali metals does not change the crystal structure and surface texture. Both Cr 6+ and Cr 3+ species exist on all catalysts, and the addition of alkali metals can increase the amount of Cr 6+ species, and Cr 6+ species are basically converted into active Cr 3+ species in the reaction thus increasing the initial propane conversion in the reaction. The addition of alkali metals reduced the amount of total acid sites and the strong acid sites of the catalyst, thus inhibiting the occurrence of side reactions and the formation of carbon deposition , and reducing the deactivation rate of the catalyst. Cr-0.5Na/Al 2 O 3 exhibited the best catalytic performance and the lowest carbon deposition.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Zongpeng Zou,Tao Zhang,Li Lv,Wenxiang Tang,Guoquan Zhang,Raju Kumar Gupta,Yan Wang,Shengwei Tang
Dry reforming of methane (DRM) presents a sustainable approach to convert greenhouse gases CO2 and CH4 into syngas. However, the industrialization of DRM is hindered by the short catalyst lifespan due to carbon deposition. Carbon deposition on Ni-catalysts is attributed to Ni step edges, which serve as carbon nucleation centers. We propose an innovative strategy to prevent carbon nucleation by modulating Ni size to eliminate Ni step edges. Ni was loaded on MCM-41, SBA-15, and DFNS (dendritic fibrous nanosilica) to prepare three distinct Ni catalysts. By altering the precursor concentration using the proposed microemulsion antisolvent coprecipitation method, we successfully adjusted the Ni size on DFNS. Ni particles with a diameter of ∼5 nm were obtained on DFNS, exhibiting excellent Ni dispersion and a physical spacing effect due to the specific preparation method and porous structure. Carbon deposition rates on Ni/MCM-41 and Ni/SBA-15 were 30.23 mgc·gcat·–1·h–1 and 16.33 mgc·gcat·–1·h–1, respectively. Remarkably, the carbon deposition rate on Ni/DFNS was only 0.15 mgc·gcat·–1·h–1. The gasification rate of deposited C to CO on the 5 nm Ni particles loaded on Ni/DFNS was five times that of the polyhedral Ni particles of Ni/MCM-41. This was attributed to the elimination of Ni step edges, which weakened C adsorption strength and enhanced the reaction of deposited C with O* to form CO. Our proposed catalyst preparation strategy is based on designing the catalyst microstructure to eliminate carbon nucleation sites. This research provides guidance for designing or preparing Ni-based catalysts for DRM with reduced carbon deposition.
研究领域:
催化化学
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材料科学
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环境科学
✓ 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）