Microporous-Ceria-Wrapped Gold Nanoparticles for Conductometric and SERS Dual Monitoring of Hazardous Gases at Room Temperature

This work proposes a novel and simple synthesis method for microporous-ceria-wrapped gold (Au@mp-CeO2) nanoparticles (NPs) based on linker molecule-induced stacking of ultrafine CeO2 particles (or beads) on the surface of pre-prepared gold NPs. The resulting NPs have a uniform size and microporous CeO2 shells with a mean thickness of 28 nm and porosity of 42%. The shell is highly tunable from about 4 to 30 nm thick. This method is universal and suitable for other metal@mp-oxide nanoarchitectures (such as Au@mp-CuO NPs, Au@mp-Cr2O3 NPs, Ag@mp-CeO2 NPs, and Ag@mp-CeO2 nanowires) simply via changing the pre-prepared metal cores or shell precursors. Most significantly, the as-prepared Au@mp-CeO2 NPs can be used for accurate monitoring of toluene vapor (10 ppm level) at room temperature based on their conductometric and surface-enhanced Raman spectroscopy (SERS) dual response. Moreover, these NPs can be also used for other hazardous gases, such as chlorobenzene, hydrogen sulfide, and 1-dodecanethiol. This excellent performance benefits from the micropore-enhanced interaction between CeO2 and gas molecules. This work not only provides new and controllable preparation for metal@mp-oxide nanoarchitectures, but also demonstrates the great potential applications of these materials in real-time and identifiable monitoring of hazardous gases.

Automated summary

This work proposes a novel and simple method for synthesizing microporous-ceria-wrapped gold nanoparticles. The method involves stacking ultrafine CeO2 particles on pre-prepared gold nanoparticles. The resulting nanoparticles have a uniform size and microporous CeO2 shells with adjustable thickness. The as-prepared Au@mp-CeO2 nanoparticles show excellent performance in accurately monitoring toluene vapor and other hazardous gases at room temperature.