The catalytic activation and conversion of small molecules such as CO, CO₂, CH₄, H₂O and NOₓ is central to the development of more sustainable chemical and energy technologies. Rather than being regarded solely as waste products or stable end molecules, many of these species can serve as valuable feedstocks for the production of chemicals, fuels and energy carriers. Their activation, however, remains a major challenge in catalysis because of their high thermodynamic and kinetic stability. Efficient conversion therefore requires catalysts capable of combining high activity, selectivity and stability, while enabling precise control over reaction pathways. For nearly three decades, our group has been investigating ceria-based and ceria-containing catalytic materials, exploiting the unique redox properties, oxygen storage capacity and structural versatility of ceria to promote catalytic activity and tune the selectivity of metal-based systems. A central theme of our research is the understanding and control of metal–support interactions, which can profoundly modify the electronic, structural and catalytic properties of the active phase. Our goal is to uncover the fundamental structure–activity–selectivity relationships governing catalytic performance and to use this knowledge to guide the rational design of more efficient catalysts. To achieve this, we combine advanced materials characterization with conventional, in situ and operando techniques, using facilities available in our laboratories and through collaborations with national and international research partners.