Polyoxometalate‐Based Metal–Organic Framework as Molecular Sieve for Highly Selective Semi‐Hydrogenation of Acetylene on Isolated Single Pd Atom Sites

Abstract Achieving highly selective acetylene semi‐hydrogenation in an ethylene‐rich gas stream is of great industrial importance. Herein, we construct isolated single Pd atom in a polyoxometalate‐based metal‐organic framework (POMOF). The unique internal environment allows this POMOF to separate acetylene from acetylene/ethylene gas mixtures and confine it close to the single Pd atom. After semi‐hydrogenation, the resulting ethylene is preferentially discharged from the pores, achieving a selectivity of 92.6 %. First‐principles simulations reveal that the adsorbed acetylene/ethylene molecules form hydrogen bond networks with oxygen atoms of SiW 12 O 40 4− and create dynamic confinement regions, which preferentially release the produced ethylene. Besides, at the Pd site, the over‐hydrogenation of ethylene exhibits a higher reaction energy barrier than the semi‐hydrogenation of acetylene. The combined advantages of POMOF and single Pd atom provides an effective approach for the regulation of semi‐hydrogenation selectivity.