期刊
SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS
卷 20, 期 1, 页码 557-567出版社
TAYLOR & FRANCIS LTD
DOI: 10.1080/14686996.2019.1608792
关键词
Complex intermetallic compounds; Al13Fe4; Al13Co4; Al13Ru4; heterogeneous catalysis; hydrogenation; butadiene; density functional theory; single-crystal surfaces
资金
- COMETE project (COnception in silico de Materiaux pour l'EnvironnemenT et l'Energie) - 'Region Lorraine'
- European Integrated Center for the Development of New Metallic Alloys and Compounds
Complex intermetallic compounds such as transition metal (TM) aluminides are promising alternatives to expensive Pd-based catalysts, in particular for the semi-hydrogenation of alkynes or alkadienes. Here, we compare the gas-phase butadiene hydrogenation performances of o-Al13Co4(100), m-Al13Fe4(010) and m-Al13Ru4(010) surfaces, whose bulk terminated structural models exhibit similar cluster-like arrangements. Moreover, the effect of the surface orientation is assessed through a comparison between o-Al13Co4(100) and o-Al13Co4(010). As a result, the following room-temperature activity order is determined: Al13Co4(100) < Al13Co4(010) < Al13Ru4(010) < Al13Fe4(010). Moreover, Al13Co4(010) is found to be the most active surface at 110 degrees C, and even more selective to butene (100%) than previously investigated Al13Fe4(010). DFT calculations show that the activity and selectivity results can be rationalized through the determination of butadiene and butene adsorption energies; in contrast, hydrogen adsorption energies do not scale with the catalytic activities. Moreover, the calculation of projected densities of states provides an insight into the Al13TM4 surface electronic structure. Isolating the TM active centers within the Al matrix induces a narrowing of the TM d-band, which leads to the high catalytic performances of Al13TM4 compounds. [GRAPHICS] .
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