Construction of Thermally Robust SERS Nanostructure for High-Temperature In Situ Analysis

High-temperature reactions serve as the basis of various modern chemical industries. Surface-enhanced Raman spectroscopy (SERS) has demonstrated significant advantages in operando characterization, particularly in the trace analysis of surface species, which is pivotal for functionality. However, its application in high-temperature processes has revealed a notable decline in sensitivity, primarily attributed to the inadequate thermal stability of the SERS amplifier. The simultaneous achievement of high SERS activity, thermal robustness, and substrate adaptability in Raman signal amplifiers stands as a pressing necessity for broadening the scope of SERS to high-temperature operando studies. This study reports a hybrid nanostructure of Au-embedded core–shell nanospheres (Au-ECSNs), which not only achieve a SERS enhancement factor higher than 104 but also exhibit thermal stability up to 600 °C, along with unrestricted substrate generality. Utilizing three-dimensional finite-difference time-domain (3D-FDTD) simulation, the optimal structural parameters of the Au-ECSNs are identified and experimentally verified by Rhodamine 6G analysis, pyridine adsorption, and thermal robustness tests. Furthermore, the feasibility of Au-ECSNs for high-temperature applications is demonstrated by the trace analysis of carbon species and dynamic monitoring of ceria nitrate decomposition under operando conditions. This work presents a potential strategy for in situ SERS analysis of high-temperature processes, particularly focusing on trace detection of surface species or dynamic monitoring of phase transformations, which is of critical importance in surface chemistry, heterogeneous catalysis, and electrochemical energy advancements.