Structurally ordered Ni3Sn2 intermetallic catalyst with well-tuned Ni sites for propyne semihydrogenation

Selective hydrogenation of propyne is essential for producing polymer-grade propylene, yet achieving high selectivity with non-precious metal catalysts remains challenging. Here, we report a structurally ordered Ni 3 Sn 2 intermetallic catalyst synthesized via topological transformation of NiSn(OH) 6 @Ni/Mg/Al layered double hydroxides. Structural characterization using X-ray diffraction, high-resolution transmission electron microscopy, and X-ray absorption spectroscopy confirms the formation of the hexagonal Ni 3 Sn 2 intermetallic phase, featuring atomically ordered and electronically modulated Ni 1 Sn 2 ensemble sites. The catalyst delivers 98.50% propylene selectivity at near-complete propyne conversion, markedly outperforming the Ni, Ni 3 Sn, and Ni 3 Sn 4 reference catalysts. Mechanistic insights from temperature-programmed surface reactions and density functional theory calculations elucidate that the superior performance arises from moderate σ-type propyne adsorption and kinetically favored propylene desorption on Ni 1 Sn 2 ensemble sites. This work demonstrates a rational intermetallic design strategy for developing high-performance, non-noble metal catalysts through precise control of active site geometry and electronic structure.