PHOTOCATALYTIC PERFORMANCE OF NATURAL SEPIOLITE AND PALYGORSKITE FOR HYDROGEN GENERATION

Highlights Natural fibrous clays sepiolite (SEP) and palygorskite (PLG) were evaluated as sustainable photocatalysts for H₂ generation from aqueous methanol under UV-C irradiation. PLG shows activation-controlled behaviour, where 24 h pre-irradiation enhances surface hydroxylation and boosts H₂ production to 564 ± 13 µmol g⁻¹, comparable to TiO₂ P25. SEP displays a decline in activity after pre-irradiation, linked to transient accumulation of methanol-derived intermediates and partial site blocking by hydroxylated fragments. FTIR, SEM, AAS, zeta potential, and XRD confirm that both minerals maintain structural integrity and experience only surface-level modifications. Demonstrates that low-cost, environmentally benign fibrous silicates can function as stable photocatalysts, offering a viable alternative to conventional semiconductors.