Amino Nests Boost Pd/SiO₂ Single‐Atom Catalysts for Efficient Selective Semi‐Hydrogenation of Acetylene

Abstract

AbstractThe selective hydrogenation of acetylene to ethylene is a critical industrial process for purifying ethylene feedstocks. Palladium single‐atom catalysts (Pd SACs) exhibit exceptional ethylene selectivity in this hydrogenation reaction. However, their isolated active sites show limited ability to capture and adsorb trace acetylene molecules from ethylene‐rich streams, resulting in relatively low hydrogenation activity. To overcome this limitation, we designed Pd single‐atom catalyst on the SiO2 surface modified with amino nests (Pd1/SiO2‐NH2). In this architecture, Pd single atoms are embedded within amino nests on the surface of SiO2‐NH2 support. Combined experimental and density functional theory (DFT) calculations reveal that amino nests selectively capture and adsorb acetylene molecules from ethylene‐rich streams, facilitating the key acetylene adsorption step. The Pd─N bonds formed between the amino nest and the Pd atom promote hydrogen activation. At 190 °C, the Pd1/SiO2‐NH2 catalyst achieves complete acetylene conversion with the ethylene selectivity of 92%. Remarkably, it delivers a specific activity of 1900.36 mol C2H2−1 molPd−1 min−1, surpassing all previously reported SACs. This work establishes an amino nest‐assisted design paradigm for single‐atom catalysts, enabling efficient, selective semi‐hydrogenation of acetylene.