Lewis-Brønsted acid-assisted pre-functionalization for the simultaneous enhancement of sulfur functionalities and textural architecture in porous carbons toward high-performance dye adsorption

Lignocellulosic biomass represents a strategic platform for achieving the global net-zero carbon pledge. The versatility of these resources enables the development of diverse upgrading strategies toward value-added products, including multifunctional porous carbon materials (PCs). Beyond their unique surface and textural features, heteroatom doping of PCs – particularly with S-containing groups – can significantly enhance surface chemistry versatility, thereby broadening their potential application range. However, current strategies used to introduce S-based functionalities often require harsh chemical conditions and/or energy-intensive processing, which may compromise the structural integrity of PCs and reduce the overall sustainability of the process. Herein, a Lewis-Brønsted acid-assisted pre-functionalization strategy is presented to simultaneously govern sulfur functionalization and textural development in PCs. This approach exploits the intrinsic reactivity of lignocellulosic-derived intermediates – including furanic and phenolic compounds – to enable the incorporation of C-S functionalities while promoting Zn-O chelate formation within a two-step synthesis, yielding S-doped PCs with high surface area and well-defined porosity. The optimized PCs exhibited surface areas of up to 1489 m 2 g -1 (approximately 50% higher than the parent material), while preserving a consistent population of O- and S-containing functionalities. The synergistic combination of tuned surface chemistry and textural properties was validated in a dye adsorption process, achieving a methylene blue adsorption capacity of up to 1086 mg g -1 . The anchoring behavior was further investigated using Advanced Statistical Physics Models, providing insights into the adsorption mechanism at the molecular level. These results highlight the potential of the proposed synthesis protocol to produce multifunctional PCs with enhanced performance for environmental remediation applications.