Catalytic activation of a non-noble intermetallic surface through nanostructuration under hydrogenation conditions

SSCI-VIDE+CATREN+LPIInternational audienceThe unique electronic and crystallographic structure of intermetallics is known to result inexcellent catalytic performances for selected chemical reactions. Moreover, a high structuralstability of the surface is generally assumed, even under reaction conditions, owing to thespecific bonding network of these compounds. Transition metal (TM = Fe, Co) aluminides ofthe Al13TM4 stoichiometry have previously demonstrated high activities and selectivities inpartial hydrogenation of alkynes and alkadienes [1]. Focusing on the Al13Co4(100) surface as a model catalyst for butadiene hydrogenation, the reaction conditions are predicted to modify the relatively flat surface structure identified under ultra-high vacuum, in the form of highly cohesive clusters emerging from the bulk lattice [2]. Unlike the flat one, this termination is catalytically active and fully selective. Its contrasted catalytic behavior as compared to that of the reference Al13Fe4(010) surface – which is more active but less selective – is rationalized in terms of alkene and hydrogen co-adsorption properties. The reaction mechanism on Al13Fe4(010) is elucidated thanks to microkinetic modeling [3]. This work demonstrates that a realistic description of the surface structures under reaction conditions is mandatory to the design of new-generation catalysts based on the complex topology of intermetallic surfaces.[1] L. Piccolo et al., Catalytic properties of Al13TM4 complex intermetallics [...], Sci. Technol. Adv. Mater. 20 (2019) 557[2] É. Gaudry et al., Catalytic activation of a non-noble intermetallic surface […], J. Mater. Chem. A 8 (2020) 7422[3] C. Chatelier et al., Mechanism of Butadiene Hydrogenation to Butene on Al13Fe4(010), to be submitted (2022