This project will investigate the exsolution of iridium nanoparticles from strontium titanate (SrTiO3) and strontium lanthanum titanate (Sr1-xLaxTiO3-d) perovskites, with the primary aim of producing catalysts with uniformly distributed, catalytically active nanoparticles for energy applications, particularly towards achieving net-zero emissions. This study will also aim to elucidate the mechanism of nanoparticle exsolution, in particular, the role of oxygen vacancies, to advance the state of knowledge of nanoparticle exsolution from perovskite parent oxides and drive us closer towards the development and widespread application of perovskite-based nanoparticle catalysts that retain their activity under operating conditions, significantly improving their lifetime before replacement.