Structured, Shaped, or Printed Single-Atom Catalysts and Their Applications

Structured catalysts, characterized by continuous, highly porous architectures, have long been recognized for their ability to enhance thermal stability, mechanical robustness, and operational efficiency in catalytic processes. Nevertheless, the use of single-atom catalysts (SACs), renowned for their exceptional atomic efficiency, in structured, shaped, or printed forms remains an emerging challenge, primarily due to the difficulties in maintaining atomic dispersion and ensuring stability under processing and reaction conditions. This review explores recent developments in the design and use of structured single-atom catalysts (collectively referred to as stru-SACs herein), focusing on their unique properties and the potential benefits of combining the atomic precision of SACs with engineered architectures. The composition of structured supports, ranging from traditional materials, such as ceramics and metals, to advanced materials, such as graphene, carbon, and aerogels, are examined. Additionally, functional active sites, innovative fabrication strategies, and advanced characterization techniques required to probe the atomic-scale environments of stru-SACs are discussed. The applications of stru-SACs are reviewed across thermocatalysis, photocatalysis, and electrocatalysis, with an emphasis on how the electronic and structural characteristics of these materials enhance the catalytic performance. Finally, current challenges and future perspectives of stru-SACs are outlined.