Synthesis of a core-shell structured catalyst with encapsulated Pd nanoparticles by molecular layer deposition(MLD)

Abstract

Core-shell structured catalyst with encapsulated Pd nanoparticles was prepared via solution-based molecular-layer-deposition(MLD). Core-shell catalyst composed of a Pd/SiO2 nanoparticle as the core and polyurea network via MLD as the shell. The synthesis procedure of catalyst involves loading Pd nanoparticles on SiO2 nanoparticles to obtain the Pd/SiO2 core and then coating a layer of polyurea network shell on the core by alternating depositions of tetrakis(4-aminophenyl)methane and para-phenylene diisocyanate. The change of shell thickness and porosity was confirmed by increasing the number of MLD cycles. It was confirmed through TEM, UV-Vis spectroscopy, FT-IR and BET respectively. We performed hydrogenation reactions while the catalyst is dispersed into the alkene reaction mixture. It was shown that catalyst covered in the polyurea network is stable and has high conversion. Also it was confirmed that the polyurea network shell has selectivity depending on the polarity of the reagent.