Defect engineering of single-atom catalysts in biomass conversion

Single-atom catalysts (SACs) have attracted intensive attention due to their highest atom utilization, especially for expensive noble metal catalysts. This article provides a comprehensive review of defect engineering in the preparation of SACs. A unique view of the synergy of single atoms and defects during biomass conversion reactions is presented. The role of defects on SACs in biomass conversion reactions is discussed. The adsorption activation mechanism, local promotion mechanism, active site renewal mechanism, and selective recognition mechanism of defects are proposed and explained. Through the classification and in-depth analysis of typical biomass conversion reactions using SACs, the promising potential of defect engineering in broader biomass upgrading is illustrated. It is hoped that this paper provides guidance for the rational design of SACs and their application in a wide range of systematic biomass conversions.