Ag-Embedded Silica Core-Shell Nanospheres for Operando Surface Enhanced Raman Spectroscopy of High-Temperature Processes.

The construction of thermally robust, highly active, and universal substrate architectures is a major challenge for high-temperature operando studies using surface enhanced Raman spectroscopy (SERS). Herein, a novel hybrid nanostructure of embedded Ag nanoparticles confined by a core-shell silica nanosphere through facile chemical synthesis is reported. Benefiting from the coupling effect of embedded Ag nanojunctions and the nanoconfinement of the silica core-shell, the hybrid nanospheres exhibit strong SERS-enhancement effects and thermal stability without restrictions on the substrate generality. Three-dimensional finite-difference time-domain (3D-FDTD) calculation indicates that the self-assembled nanojunctions of the embedded Ag nanoparticles facilitate a strong amplification of the electromagnetic field on individual nanospheres. The measurements on the trace analysis of the carbon species and dynamic tracking of the ceria lattice illustrate the feasibility of the hybrid nanospheres for the operando analysis of high-temperature processes, especially for trace detection of critical surface species or dynamic tracking of local structure evolution.