Metal nanoparticles offer numerous applications in catalysis, photocatalysis, and electrocatalysis. Our work aims to enhance the catalytic activity of metal nanoparticles through the excitation of their surface plasmon in the visible spectrum and to understand the mechanisms responsible for this enhancement. The plasmon resonance properties of metal nanoparticles can be harnessed to assist catalytic or photocatalytic reactions, notably through the hot electrons generated and the resulting thermal effect. This plasmon-assisted catalysis enables catalytic reactions to be carried out with reduced energy costs. We study reactions catalyzed by Au nanoparticles [Sarhid2019a] or Palladium of various morphologies (such as gold nanostars or Pd nanosheets) for environmental applications (water depollution) or industrially relevant reactions (C-C coupling), in collaboration with ICMMO and INSP [Sarhid2019b].