Catalytic Properties of Five-Fold Surfaces of Quasicrystal Approximants
Recently it has been shown that some low order approximants to decagonal or icosahedral quasicrystals provide excellent activity and selectivity for hydrogenation of alkynes. Our recent works on Al13Co4 and AlPd compounds demonstrated that the catalytically active surfaces in both cases are surfaces with (pseudo-)five-fold symmetry. Ab-initio DFT calculations have been used to identify the reaction centers and to construct a detailed atomistic scenario for the acetylene to ethylene hydrogenation. It was found that the activity of the catalysts is not promoted by the transition metal (TM) atoms alone but by a cluster of Al atoms centered at a slightly protruding TM atom. In the present contribution, we demonstrate that local configurations of Al and TM atoms favorable for selective catalysis of the hydrogenation reactions naturally appear at Al–TM surfaces with pentagonal symmetry. We discuss the possibility to use surfaces of the Al–TM quasicrystals and their approximants as catalysts for hydrogenation reactions.
KeywordsHydrogenation Reaction Transition Metal Atom C2H2 Molecule Ethylene Hydrogenation Icosahedral Quasicrystal
This work has been supported by the Austrian Ministry for Education, Science and Art through the Center for Computational Materials Science. M.K. thanks also for support from the Grant Agency for Science of Slovakia (No. 2/0111/11), from CEX FUN-MAT, and from the Slovak Research and Development Agency (Grant No. APVV-0647-10, APVV-0076-11).
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