Dry reforming of methane over single-atom Rh/Al ₂ O ₃ catalysts prepared by exsolution

this deactivation can be prevented by dissolution/exsolution of metal atoms into/from the support. We design and synthesise a series of single-atom catalysts, characterise them and study the impact of exsolution in the dry reforming of methane at 700-900 °C. The catalysts' performance increases with increasing reaction time, as the rhodium atoms migrate from the subsurface to the surface. Although the oxidation state of rhodium changes from Rh(iii) to Rh(ii) or Rh(0) during catalysis, atom migration is the main factor affecting catalyst performance. The implications of these results for preparing real-life catalysts are discussed.