Nickel‐Based High‐Entropy Intermetallic as a Highly Active and Selective Catalyst for Acetylene Semihydrogenation

Abstract Acetylene semihydrogenation is a key technology for producing polymer‐grade ethylene from crude ethylene. Ni‐based catalysts are promising alternatives to noble‐metals for this process. However, achieving high catalytic activity and selectivity remains a big challenge. We report a novel catalyst design based on high‐entropy intermetallics (HEI), which provide thermally stable isolated Ni without excess counterpart metals and achieve exceptionally high performance. Intermetallic NiGa was multi‐metalized to a (NiFeCu)(GaGe), where the Ni and Ga sites were partially substituted with Fe/Cu and Ge, respectively, without altering the parent CsCl‐type structure. The NiFeCuGaGe/SiO 2 HEI catalyst completely inhibited ethylene overhydrogenation even at complete acetylene conversion, and exhibited five‐times higher activity than other 3d‐transition‐metal‐based catalysts. The DFT study showed that the surface energy decreased by multi‐metallization, which drastically weakened ethylene adsorption.