Investigation\nof Sn Promoter on Ni/CeO<sub>2</sub> Catalysts for Enhanced Acetylene\nSemihydrogenation to Ethylene

Ethylene, as an important chemical raw material, could\nbe produced\nthrough the coal-based acetylene hydrogenation route. Nickel-based\ncatalysts demonstrate significant activity in the semihydrogenation\nreaction of acetylene, but they encounter challenges related to catalyst\ndeactivation and overhydrogenation. Herein, the effect of Sn promoter\non Ni/CeO<sub>2</sub> catalysts has been comprehensively explored\nfor acetylene semihydrogenation. The optimized Ni/8%Sn-CeO<sub>2</sub> catalytic performance was significantly improved, with 100% acetylene\nconversion and 82.5% ethylene selectivity at 250 °C, and the\ncatalyst maintained high catalyst performance within a 1000 min stability\ntest. A series of characterization tests show that CeO<sub>2</sub> modified by moderate Sn<sup>4+</sup> doping is more conducive to\nmodulating the charge structure and geometry of the Ni active center.\nAdditionally, the <i>in situ</i> Diffuse Reflectance Infrared\nFourier Transform Spectroscopy and density functional theory results\nindicated that catalysts doped with Sn<sup>4+</sup> facilitated more\nefficient desorption of ethylene from the catalyst surface compared\nto Ni/CeO<sub>2</sub> catalysts, thus improving ethylene selectivity\nand yield. This study highlights an effective strategy for improving\nthe catalytic performance of rare-earth-based catalysts through the\nincorporation of effective metal promoters.