Engineering dual-atom Pd Catalysts from Pd₂L₂ metal-organic cages for optimized selective hydrogenation

Dual-atom catalysts (DACs) have attracted much attention due to their abundant active sites and special catalytic performance, but the rational design and preparation of DACs are challenging. Here, we report for the first time the construction of DACs via metal-organic cages (MOCs) transformation. Specifically, a MOC, Pd2L2, formed by Pd salts and N-containing ligands, interacts with graphene, ensuring high dispersibility of MOC molecules. Subsequent thermal treatment results in the anchoring of Pd atoms onto in situ formed N-doped graphene (NG), yielding Pd dual atoms (Pd2/NG). Pd2/NG demonstrates excellent performance in the semi-hydrogenation of phenylacetylene with regard to conversion and styrene selectivity, which is superior to Pd single atoms, Pd nanoparticles, commercial Lindlar catalyst, and various reported catalysts. Computational and experimental investigations indicate that the superior catalytic performance of Pd2/NG is attributed to the synergistic effect of Pd–Pd bonds. Moreover, Pd2/NG is highly active in the selective hydrogenation of diverse alkynes to corresponding olefins.