scheme1

Scheme 1. (A) The “seesaw effect” of selectivity and activity for selective hydrogenation over monometallic and bimetallic active sites; (B) Schematic diagram of the hydrogenation process over bimetallic active sites. Note: Metal I sites are utilized to dissociate H₂ to generate ^*H species. Metal II sites selectively adsorb the substrates. The migration of ^*H from Metal I to Metal II achieves selective hydrogenation of substrates.