Abstract
Co2+/γ-Al2O3 samples were prepared by incipient wetness impregnation of γ-Al2O3 with different concentration solution of CoCl2 and dried at 40 °C. We measured the positron lifetime spectra of the samples of different Co2+ mass fractions (0%–8.24%) heated at different temperatures (100–500°C). All lifetime spectra were resolved into four components, in which the third and the fourth components were related to the surface state of the micropores and the secondary pores of the γ-Al2O3. The experimental results showed that the Co2+ was mainly located in the micropores and the secondary pores near to the exterior of the support. For low Co2+ mass fraction samples, when the heating temperature was above 400 °C, dispersal was almost finished. When the Co2+ mass fraction was above 5.59%, Co2+ and Cl− were dispersed into the secondary pores in the form of multiple layers.
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References
Peretti K L, Ajiro H, Cohen C T, et al. A Highly Active, Isospecific Cobalt Catalyst for Propylene Oxide Polymerization [J]. J Am Chem Soc, 2005, 127(33): 11566–11567.
Du Caixia. Utilization Technology for Hydrogen Adding Purification Catalyst in Hydrogen Making Raw Material [J]. Chemical Fertilizer Design, 2008, 46(2): 17–21(Ch).
Ernst B, Hilaire L, Kiennemann A. Effects of Highly Dispersed Ceria Addition on Reducibility, Activity and Hydrocarbon Chain Growth of a Co/SiO2 Fischer-Tropsch Catalyst [J]. Catal Today, 1999, 50(2): 413–427.
Van Steen E, Vijoen E L, De Loosdrecht, et al. Evaluation of Molybdenum-Modified Alumina Support Materials for Co-Based Fischer-Tropsch Catalysts [J]. Appl Catal A: Gen, 2008, 335(1): 56–63.
Pansanga K, Panpranot J, Mekasuwandumrong O, et al. Effect of Mixed γ- and χ-Crystalline Phases in Nanocrystalline Al2O3 on the Dispersion of Cobalt on Al2O3 [J]. Catal Commun, 2008, 9(2): 207–212.
Hu Bo, Zang Yaru, Wang Yueming, et al. A Surface Symmetry Model of the Metal Oxide Monolayer Supported on γ-Al2O3[J]. Chin J Catal. 1996, 17(6): 517–521(Ch).
Xie Youchang, Wang Chuanbao, Tang Youqi. The Study of the Spontaneous Dispersion of the Salt on the Surface of Carrier [J]. Sci China, Ser B, 1993, 23(2): 113–119(Ch).
Martinez A, Prieto G, Rollan J. Nanofibrous γ-Al2O3 as Support for Co-Based Fischer-Tropsch Catalysts: Pondering the Relevance of Diffusional and Dispersion Effects on Catalytic Performance [J]. J Catal, 2009, 263(2): 292–305.
Zhang Hongjun, Wang Dong, Chen Zhiquan, et al. Positron Annihilation Study of Mo Dispersion in MoO3/Al2O3 Catalysts [J]. Acta Physica Sinica, 2008, 57(11): 7333–7337(Ch).
Novakovic T, Radic N, Grbic B, et al. The Thermal Stability of Porous Alumina/Stainless Steel Catalyst Support Obtained by Spray Pyrolysis [J]. Applied Surface Science, 2008, 225(5): 3049–3055.
Zhu Jun, Wang Lili, Ma Li, Solid State Diffusion of Nacl into NaY Zeolite Studied By Positron Annihilation [J]. Acta Phys Sinica, 2003, 52(11): 2929–2933(Ch).
Kobayashi Y, Ito K, Oka T, et al. Positronium Chemistry in Porous Materials [J]. Radiat Phys Chem, 2007, 76(2): 224–230.
Goworek T. Comments on the Relation: Positronium Lifetime—Free Volume Size Parameters of the Tao-Eldrup Model[J]. Chem Phys Lett, 2002, 366(1–2): 184–187.
Zhang Yonggang, Yan Pei. Pore Structure of Activated Alumina Carrier [J]. Ind Catal, 2000, 8(6): 14–18(Ch).
Somorjai G A. Surface Science: An Old Field Rejuvenated Demands Attention and People [J]. Science, 1978, 201(4335): 489–497.
Zhu Jun, Wang Shaojie, Luo Xihui. Dispersion of Nano-Nickel into γ-Al2O3 Studied by Positron[J]. Radiat Phys Chem, 2003, 68(3–4): 541–544.
Li Guoshun, Cao Yuan, Zhang Laicun. The Reaction Steps of CoCl2· 6H2O Dehydration and Relative Kinetics [J]. J Shanxi Univ (Natural Science Edition), 1987, (2): 78–82 (Ch).
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Foundation item: Supported by the National Natural Science Foundation of China (10675093)
Biography: LI Wei(1985–), male, M. S. candidate, research direction: catalysts studied by positron.
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Li, W., Zhang, Q., Zhu, J. et al. Dispersion of CoCl2 into γ-Al2O3 studied by positron. Wuhan Univ. J. Nat. Sci. 14, 425–429 (2009). https://doi.org/10.1007/s11859-009-0511-3
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DOI: https://doi.org/10.1007/s11859-009-0511-3