Some recent advances in catalysis by metals are reviewed illustrating the versatility of supported nanoparticles and their high potential to be major contributors to solve energetic or environmental issues of the ongoing century. Since the early structure sensitivity concept, progresses have brought new insights and guidelines on structure reactivity relationships such as strain effects, the ring-capture model, the particle surface density effect, or the influence of crystallographic planes. These phenomena are proposed to play a key role in the catalytic cycle. Systematic studies are however still required to estimate their real relevance and their respective contributions according to the type of chemical reactions and of operating conditions.