Design of Core-Pd/Shell-Ag Nanocomposite Catalyst for Selective Semihydrogenation of Alkynes

Abstract

We designed core-Pd/shell-Ag nanocomposite catalyst (Pd@Ag) for highly selective semihydrogenation of alkynes. The construction of the core−shell nanocomposite enables a significant improvement in the low activity of Ag NPs for the selective semihydrogenation of alkynes because hydrogen is supplied from the core-Pd NPs to the shell-Ag NPs in a synergistic manner. Simultaneously, coating the core-Pd NPs with shell-Ag NPs results in efficient suppression of overhydrogenation of alkenes by the Pd NPs. This complementary action of core-Pd and shell-Ag provides high chemoselectivity toward a wide range of alkenes with high Z-selectivity under mild reaction conditions (room temperature and 1 atm H 2 ). Moreover, Pd@Ag can be easily separated from the reaction mixture and is reusable without loss of catalytic activity or selectivity.

Catalytic Performance of Nanoporous Metal Skeleton Catalysts for Molecular Transformations

“…Solid Pd catalysts are generally employed in the highly efficient semihydrogenation of alkynes using H 2 gas, but they often lead to over‐reduction to alkane, partial isomerization of ( Z )alkene to ( E )‐alkene, and serious leaching of Pd . Lu et al.…”

Excellent Selectivity with High Conversion in the Semihydrogenation of Alkynes using Palladium‐Based Bimetallic Catalysts

“…The most‐effective strategy is to partially substitute Pd with a second metal to form a Pd‐based alloy, in which the presence of other metal atoms can modify the electron density on the Pd atoms to give the desired selectivity. During the past few years, PdCu, PdSn, PdAg, PdGa, and PdPb alloys have been developed. One of the most attractive properties of these bimetallic alloy nanoparticles is their highly tunable composition, which results in different catalytic properties .…”

Accelerated Semihydrogenation of Alkynes over a Copper/Palladium/Titanium (IV) Oxide Photocatalyst Free from Poison and H2 Gas

“…Therefore, bimetallic catalysts have recently been investigated in detail . The forms of a bimetallic catalyst include an alloy type, a core‐shell type and other types, and the activity and selectivity of a bimetallic catalyst differ depending on the composition, state, and distribution and mixing level of the two elements in the particles . Excellent photocatalytic performance can be expected when a bimetallic catalyst is loaded on a photocatalyst as a co‐catalyst.…”