From lignin to single-atom catalysts: advances and perspectives—a review

Abstract

Lignin, the most abundant renewable aromatic biopolymer in nature, has emerged as a sustainable and versatile precursor for constructing single-atom catalysts (SACs) because of its aromatic carbon framework, high carbon content, and abundance of oxygen-containing functional groups. Recent progress has demonstrated that by regulating lignin's botanical origin, pretreatment method, and carbonization conditions, it is possible to tailor its composition, porosity, and coordination environments for diverse catalytic applications. This review provides a comprehensive overview of lignin-derived SACs encompassing four categories: noble-metal, non-noble-metal, SAC-nanocluster or alloy hybrids, and non-metal SACs. The inherent heteroatoms and hierarchical porous structure of lignin enable atomic dispersion, stabilize active centers, and fine-tune electronic structures, leading to high catalytic activity, selectivity, and durability in energy conversion, environmental remediation, and chemical synthesis. Key challenges include the heterogeneity of lignin, limited control over atom coordination, and the lack of mechanistic understanding at the atomic level. Future directions emphasize standardized pretreatment, operando and in situ characterization, theoretical modeling, and data-driven catalyst design. The incorporation of artificial intelligence tools, including large language models, is expected to accelerate data integration and rational discovery. Overall, lignin-based SACs bridge biomass chemistry and atomic catalysis, offering a sustainable pathway toward efficient, scalable, and environmentally benign catalytic systems.