Palladium Nanoparticles Supported on Magnetic Carbon‐Coated Cobalt Nanobeads: Highly Active and Recyclable Catalysts for Alkene Hydrogenation

Palladium nanoparticles are deposited on the surface of highly magnetic carbon‐coated cobalt nanoparticles. In contrast to the established synthesis of Pd nanoparticles via reduction of Pd(II) precursors, the microwave decomposition of a Pd(0) source leads to a more efficient Pd deposition, resulting in a material with considerably higher activity in the hydrogenation of alkenes. Systematic variation of the Pd loading on the carbon‐coated cobalt nanoparticle surface reveals a distinct trend to higher activities with decreased loading of Pd. The activity of the catalyst is further improved by the addition of 10 vol% Et 2 O to iso‐propanol that is found to be the solvent of choice. With respect to activity (turnover frequencies up to 11 095 h −1 ), handling, recyclability through magnetic decantation, and leaching of Pd (≤6 ppm/cycle), this novel magnetic hybrid material compares favorably to conventional Pd/C or Pd@CNT catalysts.