Synthesis and characterization of Pd(0), PdS, and Pd@PdO core–shell nanoparticles by solventless thermolysis of a Pd–thiolate cluster

Colloids of palladium nanoparticles have been prepared by the solvated metal atom dispersion (SMAD) method. The as-prepared Pd colloid consists of particles with an average diameter of 2.8±0.1 nm. Digestive ripening of the as-prepared Pd colloid, a process involving refluxing the as-prepared colloid at or near the boiling point of the solvent in the presence of a passivating agent, dodecanethiol resulted in a previously reported Pd–thiolate cluster, [Pd(SC12H25)2]6 but did not render the expected narrowing down of the particle size distribution. Solventless thermolysis of the Pd–thiolate complex resulted in various Pd systems such as Pd(0), PdS, and Pd@PdO core–shell nanoparticles thus demonstrating its versatility. These Pd nanostructures have been characterized using high-resolution electron microscopy and powder X-ray diffraction methods.