Synthesis Strategy for Protected Metal Nanoparticles

A method for synthesizing metal nanoparticle catalysts with a structured environment using atomic layer deposition (ALD) has been developed. The method involves growing uniform, dispersed Pd nanoparticles, protecting the particles with a blocking agent, growing a metal oxide structure around the nanoparticle using ALD, and removing the blocking agent. Using CO adsorption and diffuse reflectance infrared Fourier transform spectroscopy, possible blocking agents for metal nanoparticles have been evaluated based on the ability of CO to adsorb to the blocking agent–Pd nanoparticle complex. Ethylenediamine and decanethiol were found to be effective blocking agents, while acetonitrile, 1-(3-mercapto)propyl-3,5,7,9,11,13,15-isobutylpentacyclo[9.5.1.1 3,9 .1 5,15 .1 7,13 ]octasiloxane, and hexafluoroacetylacetonate were less effective. Octadecanethiol was proven to be effective in protecting Pd nanoparticles during Al 2 O 3 ALD.