Biomass-derived carbon porous frameworks: from formation mechanisms to sustainable functional materials.

Carbon porous frameworks (CPFs) are lightweight, mechanically robust materials with hierarchical porosity and tunable surface chemistry. However, conventional CPFs are predominantly produced from petroleum-derived precursors, limiting long-term sustainability. Biomass-derived carbon porous frameworks (BCPFs) offer a renewable and chemically rich alternative. Their inherent heteroatom content and oxygen-containing functional groups enable multifunctional porous frameworks through thermally driven pathways. Despite rapid progress, the fundamental relationships between biomass chemistry, thermal conversion mechanisms, and hierarchical framework formation remain poorly understood. Existing reviews primarily emphasize precursor selection or application performance, with limited discussion of the mechanisms governing structure evolution and property development. This review critically establishes mechanistic correlations between precursor chemistry, thermal conversion pathways, and resulting hierarchical porous frameworks. The distinct thermal decomposition behaviors of lignin, cellulose, and hemicellulose are discussed in relation to foamability, shrinkage, and framework stability. The major BCPF fabrication strategies are critically compared, and mechanism-guided design principles are proposed to advance scalable and sustainable BCPF development for energy storage, environmental remediation, and gas capture applications.