Optimizing Strategies of in Situ Loading Photocatalysts in Aramid Nanofiber Aerogels: Harnessing Internal/External Synergistic Photocatalysis for Improving Degradation Efficiency of Pollutants

Construction of aerogel-based composite photocatalytic materials is an effective way to completely eliminate pollutants in water. However, uniform dispersion of photocatalyst nanoparticles in porous aerogels and how to achieve efficient adsorption/photocatalysis synergy still face challenge. In this study, we have successfully addressed the challenge of achieving uniform loading of TiO₂ photocatalyst nanoparticles in aramid nanofiber (ANF) aerogels using silica aerogel powder (SAP)-assisted dispersion, which significantly broadens the spectral response range of TiO₂. The as-prepared ANF composite aerogel fibers exhibited excellent properties, such as low shrinkage (13.7%), high porosity (94.8%), and a high specific surface area (238.033 m²/g). Moreover, the as-prepared ANF/SAP/TiO₂@TiOSO₄ (M-TAST) composite aerogel film by using TiOSO₄ aqueous solution as coagulation bath achieved a synergistic effect of internal/external photocatalysis, with further improved carrier separation and migration ability, and effectively inhibited the recombination of photogenerated electron-hole pairs. Thus, the as-prepared ANF-based composite aerogel film demonstrated excellent adsorption/photocatalytic degradation of tetracycline and organic dyes. In particular, the degradation efficiency of crystal violet (CV) reached 98% in 10 min, significantly outperforming P25. Additionally, the film also exhibited good photocatalytic performance within the pH range of 2-10 and excellent recycling stability. This unique photocatalyst loading strategy is crucial for achieving adsorption and internal/external photocatalysis synergy, and the constructed M-TAST composite aerogel film shows a promising prospect for application in environmental purification.