Multisite-Cooperative Single-Atom Catalysts for Selective Upgrading of Lignocellulosic Platform Molecules: Precision Regulation and Synergistic Pathways

Single-atom catalysts, despite their exceptional activity derived from well-defined isolated sites, tend to present suboptimal performance for complex multi-step catalytic reactions. This limitation has propelled the development of more sophisticated catalytic architectures, culminating in the emergence of multisite-cooperative single-atom catalysts (MSACs), which offer a revolutionary strategy by addressing the limitations of traditional single-atom catalysts in such intricate reaction networks. Specifically, as a highly promising and rapidly evolving research frontier, the selective upgrading of lignocellulosic platform molecules represents a typical scenario involving such intricate multi-step networks. Therefore, this review comprehensively summarizes precision design strategies of MSACs, including single atom-ligand multiple sites, multi-atom sites, and single atom-cluster/nanoparticle synergies, which enable tailored coordination environments and electronic structures. The synergistic mechanisms, including electron transfer, defect-driven optimization, and atomic spacing control, are systematically elucidated as critical factors enhancing catalytic activity, selectivity, and stability. Applications across cellulose-derived molecules (e.g., HMF to FDCA oxidation), hemicellulose-based chemicals (e.g., furfural hydrogenation), and lignin valorization are extensively documented to demonstrate the efficacy of MSACs in enabling efficient reaction pathways. Finally, we discuss the remaining challenges and future perspectives of MSACs within lignocellulosic biomass valorization. We anticipate shedding some light on the forthcoming research of MSACs, thereby fostering progress in this emerging field.