Nanoparticle Growth in Supported Nickel Catalysts during Methanation Reaction—Larger is Better |
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| Authors: | Peter Munnik Marjolein E. Z. Velthoen Petra E. de Jongh Krijn P. de Jong Cedric J. Gommes |
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| Affiliation: | 1. Inorganic Chemistry and Catalysis, Debye institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands);2. Department of Chemical Engineering, University of Liège, Allée du 6 Ao?t 3, 4000 Liège (Belgium) |
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| Abstract: | ![]()
A major cause of supported metal catalyst deactivation is particle growth by Ostwald ripening. Nickel catalysts, used in the methanation reaction, may suffer greatly from this through the formation of [Ni(CO)4]. By analyzing catalysts with various particle sizes and spatial distributions, the interparticle distance was found to have little effect on the stability, because formation and decomposition of nickel carbonyl rather than diffusion was rate limiting. Small particles (3–4 nm) were found to grow very large (20–200 nm), involving local destruction of the support, which was detrimental to the catalyst stability. However, medium sized particles (8 nm) remained confined by the pores of the support displaying enhanced stability, and an activity 3 times higher than initially small particles after 150 h. Physical modeling suggests that the higher [Ni(CO)4] supersaturation in catalysts with smaller particles enabled them to overcome the mechanical resistance of the support. Understanding the interplay of particle size and support properties related to the stability of nanoparticles offers the prospect of novel strategies to develop more stable nanostructured materials, also for applications beyond catalysis. |
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| Keywords: | crystal growth heterogeneous catalysis nanoparticles nickel supported catalysts |
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