Journal of Colloid and Interface Science, Vol.488, 196-206, 2017
In-situ formation of supported Au nanoparticles in hierarchical yolk-shell CeO2/mSiO(2) structures as highly reactive and sinter-resistant catalysts
A novel strategy was described to construct Au-based yolk-shell SCVmS-Au nanocomposites (NCs), which combined the sol-gel template-assisted process for the assembly of hierarchical SCVmS NCs with modified CeO2/mSiO(2) as yolks/shells, and the unique deposition-precipitation (DP) process mediated with Au (en)(2)Cl-3 compounds for the synthesis of extremely stable supported Au nanoparticles (NPs). Characterization results indicated that the obtained SCVmS-Au NCs featured mesoporous silica shells, tunable interlayer voids, movable CeO2-modified cores and numerous sub-5 nm Au NPs. Notably, the Au(en)(2)Cl-3 was employed as gold precursors to chemically modify into the modulated yolk-shell structure through the DP process and the subsequent low-temperature hydrogen reduction induced the in situ formation of abundant supported Au NPs, bestowing these metal NPs with ultrafine grain size and outstanding sinter-resistant properties that endured harsh thermal conditions up to 750 degrees C. Benefiting from the structural advantages and enhanced synergy of CeO2-AulmSiO(2)-Au yolks/shells, the SCVmS-Au was demonstrated as markedly efficient catalysts with superior activity and reusability in catalyzing the reduction of 4-nitrophenol to 4-aminophenol, and its pristine morphology still maintained after eight recycling tests. (C) 2016 Elsevier Inc. All rights reserved.