Ni-Cu diatomic sites for efficient semi-hydrogenation of acetylene

Single-atom catalysts for alkyne semi-hydrogenation have been extensively investigated due to their high metal utilization and improved olefin selectivity. However, their reactivity is hindered by the sluggish activation of reactants on isolated sites. Herein, a non-precise metal catalyst consisting of Ni-Cu hetero-diatomic pairs was prepared using a sequential deposition method. The diatomic sites catalyst exhibited an unprecedented activity among non-precious catalysts with over 98% conversion and 77 molC2H2 molmetal−1 h−1 at 180 °C, whereas the single-atom catalysts of Cu/C and Ni/C were almost inert under the same conditions. Experimental and theoretical results revealed the crucial diatomic synergy between the Ni-Cu pairs, wherein acetylene was adsorbed on Ni sites and hydrogen was adsorbed on Cu sites, and the diatomic site enabled spontaneous desorption of ethylene. The superior activity of the diatomic catalyst was observed, resulting from the enhanced dominance of d-electrons of Ni near the Fermi level. The research demonstrates an approach to designing non-precise metal catalysts with extraordinary catalytic performance for alkyne hydrogenation.