In situ SERS and In situ Raman: Interfacial Phenomena and Processes Deciphering

Abstract

Raman and surface enhanced Raman spectroscopy (SERS) are techniques for obtaining fingerprintlike vibrational spectra information from specific substrate surfaces. Attributed to its high sensitivity towards molecular electron density distributions, Raman or SERS employed during chemical reactions can assist in analyzing detailed chemical conversion processes. However, multiple influencing factors impede the development of in situ SERS substrates and in-depth data analysis. To systematically lay out the key issue to facilitate in situ SERS probing, we document the basic principles and recent advances of in situ Raman/SERS in studying surface reactions. The mechanism and influencing factors of SERS are first briefly introduced, and the types of interface information, including the transition of species, the alteration of electron densities, the alteration of crystalline structures, are discussed in this review. We have systematically compiled species identifications and Raman spectral features reported in recent in situ studies , which are expected to serve future investigations, particularly those involving advanced computational analysis such as machine learning. Subsequently, the in situ Raman/SERS study of various types of surface reactions are discussed. Finally, the challenges and perspectives of in situ SERS in deciphering surface processes are laid out, proposing our insights for future directions and challenges. We expect the review to spread out novel ideas concerning in situ SERS and inspire further studies regarding in situ SERS techniques or surface reaction processes.