Reaction Kinetics Mechanisms and Catalysis
·
2020
·Vol. 130
·期 1
·241-256
·
IF 1.52
Ge Meng,Chen Xingye,Li Yanyong,Wang Jiameng,Xu Yanhong,Zhang Lihong
This paper describes the synthesis and application of γ -Al 2 O 3 supported SmCoO 3 perovskite-type oxide in the catalytic propane dehydrogenation to propene. Various techniques including X-ray diffraction (XRD), H 2 temperature-programmed reduction (H 2 -TPR), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and X-ray photoelectron spectra (XPS) were used to characterize the physico-chemical properties of SmCoO 3 /Al 2 O 3 and derived Co-based catalyst. The characterization results reveal that the perovskite lattice confinement can lead to better dispersed cobalt oxide and restrain the reduction to metallic Co species. Under the high weight hourly space velocity (3 h −1 ), the propane conversion and propene selectivity of the reduced SmCoO 3 /Al 2 O 3 catalyst were 25% and 94%, respectively, and obviously higher than those of the reduced SmCoO/Al 2 O 3 catalyst used as a referential sample prepared by an incipient wetness impregnation method. A large amount of coke was formed over the used SmCoO/Al 2 O 3 catalyst. Instead, the SmCoO 3 /Al 2 O 3 -derived Co-based catalyst can greatly reduce the amount of coke deposition. The superior catalytic performance and anti-coking ability of SmCoO 3 /Al 2 O 3 catalyst are attributed to the formation of a large amount of well-dispersed surface Co 2+ species, especially small CoO nanoparticles, and the absence of metallic Co species.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Science China-Materials
·
2022
·Vol. 66
·期 3
·1062-1070
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IF 8.64
Wang Yang,Chen Sai,Sun Jiachen,Xie Yufei,Zhao Zhi-Jian,Pei Chunlei,Gong Jinlong
Supported vanadium oxides (VO x ) are alternative candidates for non-oxidative propane dehydrogenation (PDH) owing to their competitive performance. This paper describes the roles of V−O sites on PDH over monomeric VO x species supported on ZrO 2 , Al 2 O 3 and SiO 2 . With the control of pre-reduction, stable structures of V−O sites are obtained for PDH, including V−O-support (V−O−S), V−OH and V=O sites. By tuning the V densities over individual support, the propylene formation rate shows a linear correlation with the number of the V−O−S site, which indicates the V−O−S site plays a decisive role in PDH rather than V−OH and V=O sites. Moreover, the specific activity per V−O−S site over ZrO 2 (8.2 × 10 −3 s −1 ) is higher than those over Al 2 O 3 (6.7 × 10 −3 s −1 ) and SiO 2 (2.8 × 10 −3 s −1 ), due to the discrepant Lewis acidity of various V−O−S sites. This research provides a fundamental insight into the intrinsic nature of V−O sites for non-oxidative propane dehydrogenation.
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
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 26
·期 4
·3263-3273
·
IF 3.3
Ziwei Zhai,Bofeng Zhang,Yutong Wang,Guozhu Liu
Based on the disturbance of electronic density, nitrogen-doped nanocarbons show promising properties to anchor metal clusters. However, precisely regulating the coordination mode between N species and the active site remains challenging. Herein, we rationally designed three N types (graphitic N, pyridinic N and pyrrolic N) in nanocarbons to anchor Pt clusters for the benchmark propane dehydrogenation. The specific activity of the pyridinic-N-doped catalyst was 147.54 molC3H6 molPt−1 h−1 at 550 °C, which was 1.3 times higher than those of graphitic- and pyrrolic-N-doped catalysts. Unlike the regular tetrahedron Pt cluster in the graphitic-N catalyst or the distorted three-layered Pt cluster in the pyrrolic-N catalyst, the Pt cluster in the pyridinic-N catalyst was an inverted tetrahedron, which increased the contact degree without geometric repulsion towards C–H bond scission. The geometric parameters of detached H and C atoms in the methylene group for the pyridinic N catalyst was decreased to strengthen the C–H bond scission. After CH3CHCH3* adsorption, the Bader charge of the Pt active site also became highly positive, which tailored the d-band center closer to the Fermi level and provided more vacant orbitals for C–H bond breakage. Therefore, pyridinic N in nanocarbons is promising to anchor small-sized Pt for alkane dehydrogenation in terms of geometric and electronic effects.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2023
·Vol. 13
·期 5
·807
·
IF 3.9
Zhiping Zhao,Zhixia Wang,Yanbing Tong,Jinru Sun,Ming Ke,Weiyu Song
The search for inexpensive, environmentally friendly, and highly effective catalysts to activate C-H bonds in propane dehydrogenation (PDH) reactions is still a major challenge. Co-based catalysts have gained significant attention in recent years due to their excellent ability to activate C-H bonds and their high selectivity towards olefins, despite being a non-noble and environmentally unfriendly metal. However, further improvements are necessary for practical utilization, particularly in terms of activity and anti-carbon deposition capacity. In this study, we synthesized Al2O3nanorods with abundant pentacoordinated Al3+(Al3+penta) sites. The supported Co on the Al2O3nanorod (Co/Al2O3-NR) exhibited higher selectivity (>96% propylene selectivity) and stability (deactivation rate 0.15 h−1) compared to Co supported on an Al2O3nanosheet with fewer pentacoordinated Al3+sites. Various characterizations confirmed that Co(II) mainly exists as CoAl2O4rather than Co3O4in the form of Co/Al2O3-NR, which inhibits the reduction of Co(II) to Co0and accordingly improves catalyst stability.Keywords:propane dehydrogenation;metal oxide;alumina;spinel
研究领域:
化学工程
·
催化材料
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2021
·
IF 3.764
Liqi Xiao,Zean Xie,Shaojia Song,Zhiping Zhao,Ming Ke,Weiyu Song,Zhen Zhao,Jian Liu
Recently, coordinated unsaturated TiO2 due to the oxygen vacancy has been found to have good application prospects in propane dehydrogenation (PDH) reactions. The oxygen vacancy can be effectively adjusted by metal doping into TiO2. In the present paper, density functional theory calculations were conducted to study the PDH reaction of TiO2 doped with transition metals in the fourth period with the aim to screen for an effective doping metal. A good linear relationship was found between the calculated turnover frequency and co-adsorption energy of H and Propyl species, justifying such co-adsorption energy as a useful descriptor for screening PDH catalysts. Compared with pure-phase TiO2, V-doped TiO2 exhibits a lower propane C–H bond breaking energy barrier (0.93 eV) and a higher TOF (5.67 × 10–3 s–1) value. According to the calculation results, the V-doped TiO2 catalyst was successfully synthesized. The experimental results show that the r(C3H6) rises with V doping.
研究领域:
材料科学
·
化学工程
·
催化反应
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2019
·
IF 8.355
Qinglong Liu,Mingsheng Luo,Zhen Zhao,Qiuna Zhao
Sn-containing dendritic mesoporous silica nanoparticles (Sn-DMSNs) were successfully prepared by the in-situ co-assembly method. Sn-DMSNs preserve original structural characteristics with three-dimensional and center-radial pore structure. The nanoparticle sizes of Sn-DMSNs can be controlled systematically from 170 nm to 360 nm depending on the molar ratio of NaSal/CTAB. Sn species are incorporated into the matrix of silica and the highly dispersed SnO x species are achieved. Sn-DMSNs catalysts exhibit excellent catalytic performance and stability in the propane dehydrogenation. The highly dispersed SnO x species rather than polymeric SnO x or crystalline SnO 2 species contribute to the activation of propane and formation of propylene. The molar ratio of NaSal/CTAB also shows an important role in the structure of support and SnO x species. The excellent stability of Sn-DMSNs catalysts can be ascribed to the good ability to restrain coke formation and strong interaction between SnO x species and silica. The effect of potassium on Sn-DMSNs catalyst is also investigated.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Surfaces and Interfaces
·
2023
·
IF 6.2
Tingyu Chen,Shuaiqi Zhao,Jiajin Lin,Yanan Chong,Yifei Li,Yun Zhao,Guangxu Chen,Yongcai Qiu
As a nontoxic and cheap catalyst, the Al 2 O 3 catalyst can be used to catalyze the propane dehydrogenation (PDH) process. However, due to its poor activity, it has been used as a catalyst carrier rather than catalysis. In this work, the experimental results indicate that γ- Al 2 O 3 -(110)-S catalysts can improve the yield of propane dehydrogenation more effectively than γ-Al 2 O 3 -(110) catalyst. We investigate the potential barrier of propane dehydrogenation reaction catalyzed by Al 2 O 3 -(110) under different conditions and found that the substitution of the S atom for partial O atom can modify the acid-base properties of the surface active site of γ-Al 2 O 3 -(110), thus reducing the reaction energy barrier. In particular, the yield of the reaction can be further improved by the active sites of oxygen vacancies generated by removing partial S atoms in γ-Al 2 O 3 -(110)-S, which is consistent with our theoretical calculation results. At the same time, theoretical calculation shows that Cu clusters can effectively remove the S atoms on the surface of γ-Al 2 O 3 -(110)-S and form oxygen vacancies. This strategy provides a new path to form oxygen vacancies on γ-Al 2 O 3 -(110), which opens up a new way for the study of propane dehydrogenation.
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
AICHE JOURNAL
·
2023
·Vol. 69
·期 12
·e18249
·
IF 3.7
Ying Zhang,Xiaofang Wang,Huihui Deng,Qin Sun,Baozhen Li,Wenchun Zheng,Zhuangzhuang Ren,Xiangqing Fang,Li Tan,Yu Tang,Lizhi Wu
Pt-based catalysts have been widely investigated in propane dehydrogenation (PDH) owing to their high activity in C H activation, while it suffers from Pt sintering and coke deposition. We develop a transition metal Fe and zeolite support synergistic-modified method to realize the highly dispersed and stable Pt species inside zeolite over Pt/Fe-silicate-1. And it shows the excellent PDH performance with propylene generation rate of 51.6 mol C 3 H 6 g Pt −1 h −1 and low deactivation rate constant k d of 0.017 h −1 as well as a high TOF Pt of 37.6 s −1 at 550°C. The systematic characterizations reveal the isolated Fe 3+ species could significantly improve Pt dispersity and regulate Pt electronic density to realize a more positive Pt δ+ species inside Silicalite-1 pore. And the further in situ DRIFTS experiments demonstrate that the synergistic effect between the appropriate acidic Fe sites and the highly dispersed Pt δ+ species around Fe species are responsible for the superior PDH performance.
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
Advanced Sustainable Systems
·
2020
·Vol. 4
·期 9
·2000092
·
IF 4.869
Zhe Wang,Yuzhuo Chen,Shanjun Mao,Kejun Wu,Kaichao Zhang,Qichuan Li,Yong Wang
Propane dehydrogenation (PDH) catalyzed by PtSn/Al 2 O 3 is a vital industrial process for producing propylene, a significant building block in the chemical industry. However, coke produced in the process deactivates the catalyst and the energy-intensive regeneration procedures can produce considerable CO 2 emission. In this work, coke on the spent catalysts is analyzed by thermogravimetric-mass spectra, Raman spectra, 1 H solid NMR spectra, and infrared spectra. Several C 3 species, including propyl, propylidene and propylidyne are found on the surface of the PtSn alloy. Several reaction pathways are investigated by density functional theory (DFT) calculations. It is also found that this coke can be hydrogenated to propylene in the PDH process. These results could provide theoretical guidance for optimizing process parameters in industry.
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
Chem
·
2020
·
IF 19.735
Sai Chen,Zhi-Jian Zhao,Rentao Mu,Xin Chang,Jun Luo,Stephen C. Purdy,A. Jeremy Kropf,Guodong Sun,Chunlei Pei,Jeffrey T. Miller,Xiaohong Zhou,Evgeny Vovk,Yong Yang,Jinlong Gong
Propane dehydrogenation (PDH) is a commercial propylene production technology that has received much attention, but high reaction temperatures result in a decrease of propylene selectivity and catalyst stability. This paper describes a single-site [PtZn 4 ] catalyst by assembling atomically ordered intermetallic alloy (IMA) as a selective and ultrastable PDH catalyst. The catalyst enables more than 95% of propylene selectivity from 520°C to 620°C. No obvious deactivation is observed within the 160-h test, superior to PtSn/Al 2 O 3 and state-of-the-art Pt-based catalysts. Based on in situ X-ray absorption fine structure, X-ray photoelectron spectroscopy measurements, and density functional theory calculations, we reveal that the surface [PtZn 4 ] ensembles in PtZn IMAs serve as the key active site structures, wherein the geometry-isolated and electron-rich Pt 1 site in [PtZn 4 ] ensembles readily promotes the first and second C–H cleavage of propane but inhibits further dehydrogenation of surface-bounded propylene. This significantly improves the selectivity and stability by prohibiting coke side reactions.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Qian Zhang,Xunzhu Jiang,Yang Su,Yang Zhao,Botao Qiao
With the increasing production of propane from shale gas and the growing demand for propylene, propane dehydrogenation (PDH) has gained significant attention as a promising route for the on-purpose production of propylene. As a cheap yet efficient catalyst, Ni-based catalysts have attracted interest because of its ability to activate alkane. Single-atom catalysts (SACs) can maximize the metal atom utilization. Here, we demonstrate that anatase TiO 2 supported Ni SAC (Ni 1 /A-TiO 2 ) exhibits not only superior intrinsic activity and propylene selectivity but also much better stability than the corresponding Ni nanoparticle (NP) catalyst (Ni NP /A-TiO 2 ) in PDH reaction at 580 °C. The rate of propylene production on Ni 1 /A-TiO 2 is about 1.96 mol C3H6 g Ni −1 h −1 , about 65 times higher than that of Ni NP /A-TiO 2 sample (0.03 mol C3H6 g Ni −1 h −1 ). In combination of high-angle annular dark-field scanning transmission electron microscopy, in-situ diffuse reflectance infrared Fourier transform spectra, in-situ X-ray photoelectron spectroscopy and X-ray absorption spectroscopy characterizations, we confirm that the Ni SAC mainly contains individual Ni atom singly dispersed on the support in positive Ni (II) valence state. In addition, as a result of strong metal-support interaction (SMSI) between Ni NP and TiO 2 carrier under reduced conditions, the Ni NPs sites are encapsulated by TiO x overlayer (~2 nm thick) thus display poor reaction performance.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Huihui Deng,Baozhen Li,Wenchun Zheng,Qin Sun,Mengjia Zhu,Jun Zuo,Yu Tang,Lizhi Wu,Li Tan
Propane dehydrogenation is one of the most promising routes for propylene production due to its single reactant, product and high economic efficiency. For Co-based catalysts, the state of Co species is one of the important factors affecting the performance of propane dehydrogenation. Here, we designed zeolite Silicalite-1 (S-1) with different silanol nests content as support to investigate the effect of silanol nests content to form Td-Co(II) species. It is found that the content of silanol nests in the S-1 supports have a linear correlation with the formation of T d -Co(II) species and corresponding PDH catalytic activity through the study of the catalyst structure-performance relationship. And the silanol nests of S-1 could be fully coordinated with 0.5 wt% Co content over 0.5Co/S-1-1-HTS in the form of T d -Co(II) species to maximize the Co atomic utilization. Correspondingly, 0.5Co/S-1-1-HTS shows the most excellent catalytic activity and stability, with C 3 H 6 generation rate of 3014 mmol C 3 H 6 g Co −1 h −1 and deactivation rate of 0.07 h −1 at 550 °C.
研究领域:
化学工程
·
催化科学
✓ 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）