Protected Single-Atom Catalysts

Catalysts are essential for producing goods in industries like energy, chemicals, and food. Precious metals and their oxides dominate this market, valued at around $20 billion annually, because of their ability to speed up chemical reactions efficiently. To maximize their performance, these materials are often used as nanoparticles, as only their surface atoms are active in catalysis. A promising innovation, single-atom catalysts (SACs), takes this efficiency even further by spreading individual metal atoms on a cheaper support material. This approach ensures every atom is utilized and often introduces unique and improved functionalities compared to larger particles. Despite their potential, SACs face challenges before they can be widely adopted. Questions remain about how single atoms attach to their support, their structural and electronic properties, and the way they drive chemical reactions. Stability is another key issue; SACs often lose their effectiveness quickly, making it critical to understand the factors that influence their durability and performance. The complexity of the support materials adds to the difficulty of fully understanding these systems. This project addresses these challenges by using simplified model catalysts with well-defined surface structures and studying them under ultra-clean conditions. A new method called "Ligand-Assisted Deposition" will be developed to create these models. This technique, inspired by atomic layer deposition methods, uses specialized molecules to precisely position single metal atoms on the support. Advanced microscopy and spectroscopy will then be used to observe how these atoms interact with reactants and drive reactions, complemented by theoretical calculations. The ultimate goal is to uncover the factors that influence SAC performance in reactions like CO oxidation and acetylene hydrogenation. By deepening our understanding of their behavior and limitations, this research aims to provide valuable insights for designing more effective and sustainable catalysts for industrial use.