Engineered covalent triazine framework inverse opal beads for enhanced photocatalytic carbon dioxide reduction

The development of highly ordered covalent triazine framework (CTF) materials with tailored structures is crucial for advancing functional material applications. Herein, we introduce a novel approach to fabricate covalent triazine framework inverse opal (CTF-IO) photonic crystal beads via a microfluidic-assisted assembly method and pore-confined polymerization. The polymerization process occurs within the interstitial voids of SiO₂ nanoparticles (NPs) photonic crystals, where spatial confinement dictates the growth and arrangement of the CTF framework, resulting in a robust and precisely ordered inverse opal (IO) structure. The pore sizes, governed by the packing geometry of SiO₂ NPs, are theoretically estimated to highlight the role of confinement in achieving structural fidelity. The unique slow-light effect of the CTF-IO structure enhances light absorption and charge transport, offering a versatile platform for light-driven CO₂ conversion applications. As a demonstration, the optimized CTF-240 exhibit superior photocatalytic performance in CO₂ reduction, achieving a yield of 118.69μmol g^-1h^-1 and a selectivity of 97.25 % without sacrificial agents or co-catalysts, significantly outperforming bulk CTF. This work underscores the potential of photonic crystal-guided framework design for diverse advanced applications, providing insights into the interplay between spatial confinement, structural engineering, and functional performance.