Plasmon driven photocatalytic reactions monitored by surface enhanced Raman spectroscopy Plasmonic metal nanostructures can be tuned to efficiently interact with light converting the photons into energetic charge carriers and heat. Therefore the plasmonic nanoparticles such as gold and silver nanoparticles act as nano reactors where the molecules attached to their surfaces benefit from the enhanced electromagnetic field along with the generated energetic charge carriers and heat for possible chemical transformations. Hence plasmonic chemistry presents metal nanoparticles as a unique playground for chemical reactions on the nanoscale remotely controlled by light. However defining the elementary concepts behind these reactions represents the main challenge for understanding their mechanism in the context of the plasmonically assisted chemistry. Surface enhanced Raman scattering (SERS) is a powerful technique employing the plasmon enhanced electromagnetic field which can be used for probing the vibrational modes of molecules adsorbed on plasmonic nanoparticles. In this cumulative dissertation I use SERS to probe the ...