Achieving the Trade‐Off between Selectivity and Activity in Semihydrogenation of Alkynes by Fabrication of (Asymmetrical Pd@Ag Core)@(CeO₂ Shell) Nanocatalysts via Autoredox Reaction

Abstract

(Asymmetrical Pd@Ag core)@(CeO shell) nanostructures are successfully fabricated via a clean and facile modified autoredox reaction by the preaddition of Pd seeds in the growth solution. In a subsequent catalytic test, it is found that the as-obtained bimetallic core@shell nanoparticles exhibit excellent catalytic performance in semihydrogenation of alkynes. The trade-off between selectivity and activity is well realized.

Facile Fabrication of Highly Dispersed Pd@Ag Core–Shell Nanoparticles Embedded in Spirulina platensis by Electroless Deposition and Their Catalytic Properties

“…In addition, as mentioned above, further increase of the Ag layer thickness of Pd@Ag NPs will cause the catalytic activity decrease, suggesting that the suitable thickness of the Ag layer is important for this core–shell configuration toward an optimized catalytic property. Previous reports demonstrate that in Pd@Ag core@shell nanostructures the Pd core can serve as a hydrogen source by the formation of PdH species to accelerate the catalytic activity of the outer metal; for the Pd@Ag NPs with a thicker Ag layer, the formation of PdH species will be more difficult and resulting in a low catalytic activity. Therefore, herein the excellent catalytic activity of Pd@Ag NPs in ( Pd@Ag ) @Sp‐5 composites is mainly attributed to the synergistic effect of the Pd core and the Ag layer with preferable thickness.…”

“…Therefore, herein the excellent catalytic activity of Pd@Ag NPs in ( Pd@Ag ) @Sp‐5 composites is mainly attributed to the synergistic effect of the Pd core and the Ag layer with preferable thickness. On the one hand, the proper thickness of Ag ensures the surface charge state of the outer Ag layer favorable for the dissociation rate of H 2 molecules, resulting in the increase of the catalytic activity. On the other hand, with proper thickness of Ag, Pd cores can serve as a hydrogen source by the formation of PdH species, which can largely accelerate the catalytic activity of the outer Ag layer.…”

Hollow Structure and Electron Promotion Effect of Mesoporous Pd/CeO2 Catalyst for Enhanced Catalytic Hydrogenation

“…The obtained high catalytic activity on the Pd/CeO 2 ‐H catalyst could be reasonably interpreted by elaborating the close interactions between catalytically active metallic Pd and the CeO 2 support as well as the reaction pathway on the hollow sphere catalyst. In the case of the extraordinary catalytic activity and reusability, some CeO 2 ‐based noble metal nanocatalysts with core–shell structure also exhibited excellent catalytic hydrogenation performance, which was attributed to the confined structure and interaction between CeO 2 shell and noble metals …”

High Catalytic Activity of C60Pdn Encapsulated in Metal–Organic Framework UiO‐67, for Tandem Hydrogenation Reaction

“…Among three UiO‐67 supported catalysts, Pd@UiO‐67 presented lower conversion (80 %) and selectivity (60 % for A ) than the target one, whereas C 60 @UiO‐67 without Pd showed very weak activity with less than 10 % conversion rate under similar conditions (the reaction time extended to 6 h). This comparison implies that Pd NPs have intrinsic hydrogenation activity, and when combined with C 60 , the catalytic activity (including conversion and selectivity) will be significantly enhanced. In addition, the other two catalysts without MOF support, but with Pd particles, also gave poorer performance whereby C 60 Pd n showed 90 % conversion rate and 5 % selectivity for A during an extended reaction time, and commercial Pd/C presented just 50 % conversion rate and 38 % selectivity for A under the same conditions.…”