Carbon-based single-atom catalysts derived from biomass: Fabrication and application

Single-atom catalysts (SACs) with active metals dispersed atomically have shown great potential in heterogeneous catalysis due to the high atomic utilization and superior selectivity/stability. Synthesis of SACs using carbon-neutral biomass and its components as the feedstocks provides a promising strategy to realize the sustainable and cost-effective SACs preparation as well as the valorization of underused biomass resources. Herein, we begin by describing the general background and status quo of carbon-based SACs derived from biomass. A detailed enumeration of the common biomass feedstocks (e.g., lignin, cellulose, chitosan, etc.) for the SACs preparation is then offered. The interactions between metal atoms and biomass-derived carbon carriers are summarized to give general rules on how to stabilize the atomic metal centers and rationalize porous carbon structures. Furthermore, the widespread adoption of catalysts in diverse domains (e.g., chemocatalysis, electrocatalysis and photocatalysis, etc.) is comprehensively introduced. The structure-property relationships and the underlying catalytic mechanisms are also addressed, including the influences of metal sites on the activity and stability, and the impact of the unique structure of single-atom centers modulated by metal/biomass feedstocks interactions on catalytic activity and selectivity. Finally, we end this review with a look into the remaining challenges and future perspectives of biomass-based SACs. We expect to shed some light on the forthcoming research of carbon-based SACs derived from biomass, manifestly stimulating the development in this emerging research area.