Construction of 3D Ordered Honeycomb Films with Controllable Pores as Efficient Catalytic Supports

The facile construction of 3D porous film using the breath figure technique is critically important in diverse practical applications. However, the discovery of easy synthetic methods and preparation of stimuli‐responsive 3D ordered nano‐/micro‐architectures remain challenging. Herein, the promotive breath figure technique is presented to construct 3D honeycomb porous films on curved substrates using an azobenzene‐containing copolymer. The nanopore size of honeycomb structure decreases gradually with the increase of surface curvature, due to the different solvent drying speeds. Upon irradiation with directional linear polarization light, the round‐shaped nanopores are converted into rectangular‐ and rhombic‐shaped nanopores under different polarization directions. Moreover, these porous films are employed as substrates to load various metal nanoparticles, successfully preparing the nanocomposites. The catalytic capacity of both control and these nanocomposites are evaluated using the NaBH4‐mediated reduction reaction from 4‐nitrophenol to 4‐aminophenol. Compared to the control and nonporous films, the porous films with smaller nanopores exhibit larger catalytic activity. Additionally, UV irradiation upon the nanocomposites promotes the catalytic action, due to the change in surface hydrophilicity caused by the photoisomerization of azobenzene. Recyclable use of nanocomposites demonstrates the high stability. This research provides an innovative strategy to prepare 3D curved porous films for potential on catalysis. The application potential of porous films from the breath figure technique is currently limited by the preparation of spatial dimensions and stimuli responsiveness. Herein, photo‐responsive 3D porous films with controllable and uniform nanopores are generated using Azo‐copolymers as subunits, subsequently loading noble nanoparticles onto their surface to generate the smart nanocomposites for potential recyclable use in nanocatalysis.