One-pot synthesis of core–shell Au@CeO2−δ nanoparticles supported on three-dimensionally ordered macroporous ZrO2 with enhanced catalytic activity and stability for soot combustion

Abstract

A series of multifunctional catalysts of three-dimensionally ordered macroporous (3DOM) ZrO2-supported core–shell structural Au@CeO2−δ nanoparticles were successfully synthesized by the one-pot method of gas bubbling-assisted membrane reduction–precipitation (GBMR/P). All the catalysts possess a well-defined 3DOM structure with interconnected networks of spherical voids, and the Au@CeO2−δ core–shell nanoparticles with different molar ratios of Au/Ce are well dispersed and supported on the inner wall of the uniform macropore. 3DOM support facilitates the contact efficiency between solid reactant and catalyst, and the Au@CeO2−δ core–shell nanoparticles with strong metal-oxides interaction improve the amount of active oxygen species and the sintering resistance of supported Au nanoparticles due to the optimization of the interface area by formation of the metal-oxides core–shell (MOCS) nanostructure particles. 3DOM Au@CeO2−δ/ZrO2 catalysts exhibit high catalytic activity and stability for diesel soot oxidation. Among the as-prepared catalysts, 3DOM Au@CeO2−δ/ZrO2-2 catalyst with the moderate thickness of CeO2−δ nanolayer shell shows the highest catalytic activity for soot combustion, i.e., its T50 is 364 °C. In summary, 3DOM Au@CeO2−δ/ZrO2 catalysts are excellent systems for catalytic combustion of solid particles or macromolecules, and the design concept and facile synthesis method of 3DOM oxide-supported MOCS nanoparticle catalysts can be extended to other metal/oxide compositions.