Catalysis Science & Technology
·
2018
·Vol. 8
·期 17
·4338-4348
·
IF 5.365
Xiaoli Yang,Xiong Su,Binglian Liang,Yaru Zhang,Hongmin Duan,Junguo Ma,Yanqiang Huang,Tao Zhang
The oxide–zeolite process has been attracting widespread attention due to its promising performance in syngas conversion to hydrocarbons with high selectivity and stability. Here, a composite catalyst containing Zn–Cr oxide and ZSM-5 zeolite provides a competitive option in the one-step conversion of syngas into C5+ hydrocarbons. In order to figure out the influence of the pore structure and acidity of zeolite on the oxide–zeolite process, alkali treatments on ZSM-5 are carried out. The treated ZSM-5 shows increased selectivity for gasoline fractions. With a set of structural and morphological characterization techniques, the formation of a hierarchical porous structure is demonstrated, which is favorable for the diffusion of heavy products. Furthermore, an increase in the number of Lewis acid sites, acting as the main active sites for the polymerization, cyclization and aromatization reactions, also contributes to the promotion of C5+ hydrocarbon production. It must be noted, however, that a certain amount of Brønsted acid sites is necessary for the tandem transformation of CH3OCH3 intermediates, which may further affect the CO conversion.
研究领域:
催化化学
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Hu Wang,Bingxia Wu,Yuan Cai,Chengwei Zhou,Nengjie Feng,Geng Liu,Chong Chen,Hui Wan,Lei Wang,Guofeng Guan
The core–shell-structured Co–Z@TiO2(N2+O2) catalyst, which was prepared by subsequent pyrolysis and calcination from precursor ZIF-67 coated by amorphous TiO2, was applied in Fischer–Tropsch synthesis (FTS). Compared with Co–Z@TiO2 catalyst, which was directly calcinated in air (Co–Z@TiO2(O2)) or pyrolyzed in N2 (Co–Z@TiO2(N2)), the Co–Z@TiO2(N2+O2) catalyst showed better dispersion, easier reducibility, and optimal metal cobalt particle size (8.4 nm) due to the intermediate pyrolysis treatment and core–shell structure. The Co–Z@TiO2(N2+O2) catalyst exhibited high cobalt time yield (14.84 μmolCO·gCo–1·s–1), high selectivity to C5+ (81.5%), and low selectivity to low carbon hydrocarbon (CH4 (12.7%) and C2–C4 (5.8%)). The core–shell structure could enhance diffusion limitations to transform intermediate products into heavier hydrocarbons. After 110 h of evaluation, the Co–Z@TiO2(N2+O2) catalyst still maintained good catalytic performance and cobalt particle size distribution.
研究领域:
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2018
·
IF 3.141
Junhui Liu,Anfeng Zhang,Xiao Jiang,Min Liu,Jie Zhu,Chunshan Song,Xinwen Guo
Conversion of CO2 by hydrogenation into higher hydrocarbons has attracted much attention due to the continuous increasing concentration of CO2 in the atmosphere. Fe5C2 was used as the active site and mixed with K-modified supports for CO2 hydrogenation to synthesize value-added hydrocarbons. A series of supports were tested, and the alkaline Al2O3 was the best choice for light olefins and C5+ hydrocarbons. The transformation of product selectivity at time on stream demonstrated that potassium migrated into Fe5C2 during reaction. The selectivity of C2+ is 69.2% containing 35.8% C2–C4= and 29.1% C5+ value-added hydrocarbons with the 31.5% CO2 conversion (H2/CO2 = 3). When the ratio of H2 and CO2 was switched to 4, CO2 conversion improved to 40.9%, and the C2+ selectivity to 73.5%, containing 37.3% C2–C4= and 31.1% C5+ value-added hydrocarbons. The mixture catalysts can be directly used without any reduction before reaction, reducing the consumption H2 and simplifying the operation.
研究领域:
催化化学
·
能源化学
·
环境科学
·
材料化学
·
工业催化
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yan Liu,Lei Li,Junfeng Zhang,Bo Hou
Optimizing metal nanoparticle size, dispersion, accessibility, and metal-support interaction has proven impactful for Fischer-Tropsch synthesis (FTS) activity, selectivity of long-chain hydrocarbons and stability. Herein, the Co/Al 2 O 3 -CAI catalyst was successfully prepared by a coordination-assisted impregnation strategy. Compared with Co/Al 2 O 3 -EWI catalyst prepared by traditional impregnation method, the Co/Al 2 O 3 -CAI catalyst displayed superior FTS performance with a low methane selectivity (3.2 %) and surprisingly high C 5+ hydrocarbons selectivity (94.0 %) within 200 h reaction time. The catalyst remained excellent stability with ca. 40 % CO conversion even after 1600 h on stream. It revealed that the high dispersion of cobalt species as well as reduced CoAl 2 O 4 spinel could be achieved via a coordination-assisted impregnation strategy, which provide the increased number of surface-exposed Co sites. Meanwhile, the relatively strong metal-support interaction facilitated surface confinement of cobalt species and electron transfer, guarantying catalyst stability under long-term FTS process. This work provides a new insight into the design of highly efficient and stable catalysts for FTS reaction.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2016
·
IF 7.354
Liang Wei,Yanxi Zhao,Yuhua Zhang,Chengchao Liu,Jingping Hong,Haifeng Xiong,Jinlin Li
Three-dimensional mesoporous cellular silica foams (MCFs) were prepared and used as supports for cobalt Fischer–Tropsch synthesis (FTS) catalysts (Co/MCF). The silica foam MCFs have a 3D mesostructure with large spherical cell pores interconnected with small window pores, which provides an open porous network for Co FTS catalysts. The effects of catalyst structure parameters (cell pore diameter and cobalt particle size) on the performance of the Co/MCF catalysts were investigated. It was found that the Co/MCF catalyst with average pore size 7–12 nm (window and cell pores) showed the highest reactivity. The MCF not only provided a cavity to suppress the growth of cobalt particles, but also enhanced the reducibility and cobalt dispersion. The Co/MCF catalysts having a large and open pore structure are favorable for the transport of reactants and the occurrence of secondary reactions, leading to high C 5+ hydrocarbon selectivity. A Co/MCF catalyst with Co particle size 6.9 nm presented the highest activity in the FTS reaction due to its having the highest dispersion and an appropriate degree of reduction. Compared with the Co catalysts supported on other ordered silicas (SBA-16, KIT-6, and SBA-15), the Co/MCF catalyst showed higher activity and C 5+ hydrocarbon selectivity, which was attributed to the 3D open porous structure of MCF. The Co/MCF catalysts are stable under low-temperature FTS conditions (210 °C). Under harsh FTS reaction conditions (250 °C, 1.0 MPa), the Co/MCF catalyst underwent rapid deactivation due to cobalt sintering and the formation of interacting Co–silica compound, while the stability of the Co/MCF catalyst can be improved by functionalizing the MCF using carbon coating and Al doping.
研究领域:
化学工程
·
材料科学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Qiuyao Jiao,Yan Liu,Ran Yu,Lei Li
For supported heterogeneous catalyst, metal-support interaction (MSI) is very important factors for catalytic performance. Commercial γ-alumina was reduced with hydrogen in advance, providing strong anchoring sites for metal (metal oxide) species. This research demonstrates the use of pre-reduced alumina as catalyst carrier to anchor metal Co species in FTS compared with unreduced one. The defective alumina supported catalyst displayed a supeior performance. The Co/RAl2O3-550 catalyst showed surprisingly high CO conversion of 56.0%, C5+ hydrocarbons selectivity of 93.2%, and a low methane selectivity of 2.7% at a remarkable high activity (CTY = 1.1 × 10-5 molCO gCo-1 s−1). It revealed the strong reduction of alumina generated more defective sites, which was strongly anchored with metal cobalt species under MSI. Besides, the reduction of alumina also boosted the number of surface L-acidity, promoting the CO absorption rate through CO dissociation. These results reveal the unique property of defective Al2O3 supported cobalt catalysts, and provide a practical strategy to explore stable and efficient FTS catalysts.
研究领域:
催化化学
·
材料科学
·
化学工程
·
表面化学
✓ 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）