Acid-pretreated sepiolite fibers in enhancing TiO2/SiO2 aerogel integrity and photocatalytic activity

TiO 2 /SiO 2 composite aerogels hold promise for photocatalytic environmental remediation but suffer from mechanical instability-induced structural collapse under thermal stress; this study addresses this limitation via fiber reinforcement to enhance mechanical robustness while preserving functionality. Sepiolite fibers were integrated into TiO 2 /SiO 2 aerogels to enhance structural integrity, with fiber pretreatment and concentration systematically optimized to balance morphology, stability, and photocatalytic efficiency. The results confirmed that nitric acid-pretreated sepiolite fibers effectively enhanced framework integrity while preserving low density (0.457 g cm −3 ) and high specific surface area (144 m 2 g −1 ). Photocatalytic evaluation demonstrated complete degradation of Rh B solution within 10 h under UV irradiation for the optimized composite. Within the TiO 2 /SiO 2 aerogel system, the incorporation of acid-treated sepiolite fibers enhances surface hydrophilicity, leading to improved interfacial bonding strength between the fibers and the matrix, thereby increasing the overall mechanical strength. Concurrently, the expansion of nanopores within the fibers contributes to an increase in specific surface area. Furthermore, the high purity of these fibers minimizes recombination centers for photogenerated electron–hole pairs, thus preserving photocatalytic activity. This work establishes a viable pathway for developing mechanically robust aerogel photocatalysts with sustained catalytic performance and enhanced recyclability.