Carburization induced phase transition of <scp>Ni₃In</scp> to <scp>Ni₃InC</scp>_0.5 intermetallic carbide for acetylene semihydrogenation

Abstract In this work, we develop a carburization strategy to transform hexagonal Ni 3 In into face‐centered cubic Ni 3 InC 0.5 intermetallic carbide, leveraging partially isolated Ni sites for improved acetylene semihydrogenation. The catalyst synthesized via carburization of Ni 3 In intermetallic compound derived from Ni/In/Mg/Al layered double hydroxides in a C 2 H 2 /H 2 atmosphere is evidenced to show Ni 3 InC 0.5 intermetallic carbide phase through detailed characterizations, including high‐resolution transmission electron microscopy and X‐ray absorption spectroscopy. Catalytic tests reveal that the Ni 3 InC 0.5 catalyst achieves 92.0% ethylene selectivity at full acetylene conversion, outperforming the Ni and Ni 3 In catalysts. Both experimental and theoretical evidence demonstrate that interstitial carbon atoms in Ni 3 InC 0.5 synergize with neighboring In atoms to modify the electronic structure of surface Ni sites via significant hybridization between Ni 3 d , In 5 p , and C 2 p orbitals. These unique features enable higher kinetic favorability of ethylene desorption over its further hydrogenation on the Ni 3 InC 0.5 catalyst and thus contribute to the enhanced semihydrogenation.