Advances in porous activated carbon-based solid acid catalysts for biomass conversion

Porous activated carbon-based solid acid catalysts (AC‑SACs) have gained significant attention as promising materials for biomass conversion due to their high surface area, tunable porosity, and strong acidic functional groups. Biomass conversion is essential for the sustainable production of biofuels, including biodiesel, and other value‑added chemicals, offering an alternative to fossil-based resources. This review summarizes recent advances in the synthesis, characterization, and catalytic performance of AC‑SACs, emphasizing their role in key biomass conversion reactions such as hydrolysis, dehydration, esterification, transesterification, and catalytic pyrolysis. Synthesis strategies encompassing biomass pretreatment, carbonization, activation, and subsequent sulfonation or other functionalization methods are discussed in relation to their impact on hierarchical pore architecture, surface chemistry, and Brønsted/Lewis acidity. The review also examines primary deactivation mechanisms of AC‑SACs-such as -SO₃H leaching, chemical derivatization of acid sites, and thermal degradation-and highlights regeneration strategies and design principles for improving long‑term stability. Future research directions are proposed, focusing on enhancing functional group stability, integrating regeneration into process design, and expanding AC‑SAC applications in sustainable chemical processes. The findings underscore the potential of AC‑SACs as versatile and environmentally friendly catalysts for biomass valorization and green chemistry applications.