Synthesis of a hollow structured core–shell Au@CeO2–ZrO2 nanocatalyst and its excellent catalytic performance

Abstract

We proposed a hard-templated and electrostatic attraction induced deposition method to prepare a hollow core–shell Au@CeO₂–ZrO₂ nanocatalyst with a high surface area, in which a 6–8 nm ultrathin layer composed of CeO₂–ZrO₂ nanocrystals is embedded with individual Au nanoparticles, forming a sub-10 nm core–shell-like structure. In this hollow core–shell nanocatalyst, the mobility and growth of Au nanoparticles can be well inhibited even at 700 °C. For two model reactions of the selective reduction of 4-nitrophenol and CO oxidation, this Au@CeO₂–ZrO₂ nanocatalyst shows good catalytic activity and stability, compared with Au/CeO₂–ZrO₂ prepared by the deposition–precipitation (DP) method. For the CO oxidation, the activity of Au@CeO₂–ZrO₂ can be well maintained after calcination at 700 °C, while negligible CO conversion is observed over DP-Au/CeO₂–ZrO₂. Further research shows that the improved catalytic performance of this hollow core–shell nanocatalyst can be attributed to the nanoscale core–shell structure, which effectively inhibits the migration and growth of the Au NPs, and maximizes the interface between the Au NPs and the CeO₂–ZrO₂.