RESUMEN
Atomically ordered intermetallic compounds (IMCs) have been extensively studied for exploring catalysts with high activity, selectivity, and longevity. Compared to random alloys, IMCs present a more pronounced geometric and electronic effect with desirable catalytic performance. Their well-defined structure makes IMCs ideal model catalysts for studying the catalytic mechanism. This review focuses especially on elemental composition, electron transfer, and structure/phase evolution under high temperature treatment conditions, providing direct evidence for the migration and rearrangement of metal atoms through electron microscopy. We then present the outstanding applications of IMCs in growing single-walled nanotubes, hydrogenation/dehydrogenation reactions, and electrocatalysis from the perspective of electronic, geometric, strain, and bifunctional effects of ordered IMCs. Finally, the current obstacles associated with the use of in situ techniques are proposed, as well as future research possibilities.
RESUMEN
Fabricating optimum surface structures represents an attractive approach for synthesizing supported catalysts with high activity and specific selectivity. New active sites could be flexibly constructed via the strong metal-support interaction under the redox condition. Herein, we demonstrated the formation of a new Rh-Si surface on a silica-modified carbon nanotube supported Rh catalyst under the high-temperature reduction condition as well as a thin amorphous silica coating layer and weak chemisorption toward the CO molecule. The electronic interactions between Rh and Si, along with the particular structure, guarantee desirable catalytic performance for the semihydrogenation of phenylacetylene under mild conditions. This facile approach might be extensively used in constructing new active sites with robust activity and specific selectivity in diverse heterogeneous catalysis systems.