Asymmetric Coupled Binuclear‐Site Catalysts for Low‐Temperature Selective Acetylene Semi‐Hydrogenation

Abstract

AbstractHeterogeneous metal catalysts with bifunctional active sites are widely used in chemical industries. Although their improvement process is typically based on trial‐and‐error, it is hindered by the lack of model catalysts. Herein, we report an effective vacancy‐pair capturing strategy to fabricate 12 heterogeneous binuclear‐site catalysts (HBSCs) comprising combinations of transition metals on titania. During the synthesis of these HBSCs, proton‐passivation treatment and step‐by‐step electrostatic anchorage enabled the suppression of single‐atom formation and the successive capture of two target metal cations on the titanium–oxygen vacancy‐pair site. Additionally, during acetylene hydrogenation at 20 °C, the HBSCs (e.g., Pt1Pd1−TiO2) consistently generated more than two times the ethylene produced by their single‐atom counterparts (e.g., Pd1−TiO2). Furthermore, the Pt1Pd1 binuclear sites in Pt1Pd1−TiO2 were demonstrated to catalyze C2H2 hydrogenation via a bifunctional active‐site mechanism: initially C2H2 chemisorb on the Pt1 site, then H2 dissociates and migrates from Pd1 to Pt1, and finally hydrogenation occurs at the Pt1−Pd1 interface.