Confined Ostwald ripening approach towards highly durable and flexible 3D PTFE aerogels boosting Pickering emulsion separation in bi-phase photocatalysis

Aerogel, characterized by ultra-low density and scalable preparation, is extensively utilized in various applications, such as catalysis, adsorption/separation, and thermal insulation. However, the trade-off between durability and flexibility for aerogels remains a fundamental challenge, limiting their further development in harsh and complicated conditions. Herein, we developed a confined Ostwald ripening approach to construct the first example of 3D polytetrafluoroethylene (PTFE) aerogel without additional binders. This aerogel possessed an ultra-low density of 0.042 g·cm −3 , vertically aligned channels, and complex superhydrophobic surface structure, which realized the highest oil flux (5.09 × 10 5  L·m −2 ·h −1 ) in the ultra-fast oil/water separation so far. This excellent performance could be maintained in strong acid, alkaline, corrosive organic, or complicated emulsion solutions. Moreover, this pure PTFE skeleton exhibited a high Young's modulus of 0.08 MPa, an elastic modulus of 5.24 × 10 −4  MPa, and excellent flexibility. Following, the 3D PTFE aerogel was employed in Pickering emulsion bi-phase photocatalysis for highly efficient photocatalyst cycling and product separation. This work not only addresses the inherent poor processability of PTFE but also breaks the trade-off between durability and flexibility for aerogels, which greatly boosts its development in long-term practical applications under harsh and complicated conditions.