Synthesis of dendritic porous silica nanospheres coated by polymer layer with well-dispersed ultrasmall Pt nanoparticles

Abstract It is highly desired but challenging to achieve uniform and high-density loading of ultrasmall active species on porous carriers for excellent performance in various applications. Herein, we successfully used aminopropyl-modified dendritic porous silica nanospheres (DPSNs-NH2) as a carrier to prepare the polymer-coated DPSNs-NH2 with many ultrasmall Pt NPs by one-step ammonia-catalyzed resorcinol-formaldehyde (RF) resin polymerization and formaldehyde-caused H2PtCl6 reduction (named as DPSNs-NH2@RF@Pt nanocomposite). High-density Pt NPs with a mean size of ca. 0.9 nm are uniformly dispersed on and in the RF resin layer, which is coated on the surface of center-radial large pores of DPSNs. In addition, the thickness of RF resin layer can be simply adjusted by tuning the amount of precursors. DPSNs-NH2@RF@Pt nanocomposite exhibits excellent structure stability upon long time ultrasonic treatment, which should be mainly attributed to the partial embedding of Pt NPs on and in the RF resin layer. These results should provide some insight for the design and construction of the supported nanocatalysts.