Recent Advances in Sustainable Single-Atom Catalysts from Biomass and Solid Waste: Design, Synthesis and Applications.

Single-atom catalysts (SACs), featuring isolated metal atoms anchored on engineered supports, have emerged as a transformative class of catalytic materials. Their atomically dispersed active sites enable nearly 100% metal utilization, unique electronic structures, and highly tunable coordination environments, which results in exceptional activity and selectivity across diverse reactions. Recently, sustainable single-atom catalysts (Sus-SACs) derived from biomass and solid waste have garnered increasing attention. The development of Sus-SACs not only provides a low-cost and renewable pathway for SAC fabrication but also aligns with global goals of carbon neutrality and the circular economy. This review presents a comprehensive overview of the current progress in Sus-SACs. First, the typical biomass- and solid waste-derived precursors are introduced. The synthesis methodologies are thoroughly discussed, with particular emphasis on ultrafast synthesis approaches that hold promise for scalable production. State-of-the-art techniques for structural characterization of single-atom sites are further summarized, alongside the introdcution of emerging applications of artifical intelligence in the rapid precursor screening, design, synthesis and characterizations of Sus-SACs. Recent catalytic applications in electrocatalysis, chemical synthesis and upgrading, and environmental remediation are systematically evaluated. Finally, the key challenges and future opportunities are outlined to guide the continued advancement and industrial translation of Sus-SACs. Overall, this review aims to provide a comprehensive summary of developments in this rapidly evolving field and to offer insights for addressing the critical challenges that remain.