3D-Printed Organic Conjugated Trimer for Visible-Light-Driven Photocatalytic Applications

Small molecule organic semiconductors (SMOS) have emerged as a new class of photocatalysts that exhibit visible light absorption, tunable bandgap, good dispersion, and solubility. However, the recovery and reusability of such SMOS in consecutive photocatalytic reactions is challenging. In this work, we report a 3D-printed hierarchical porous structure based on an organic conjugated trimer, named EBE. Upon manufacturing, the photophysical and chemical properties of the organic semiconductor were maintained. Interestingly, the 3D-printed EBE photocatalyst showed a longer lifetime compared to the powder-state EBE. This result indicates a microenvironment effect of solvent, a better dispersion of the catalyst in the sample, as well as a reduced intermolecular 𝜋-𝜋 stacking, which results in improved charge pair separation. As a proof-of-concept, we evaluated the photocatalytic activity of the 3D-printed EBE catalyst for water treatment and hydrogen production under sun-like irradiation. The resulting degradation efficiencies and hydrogen generation rates are higher than the ones reported for the state-of-the-art 3D-printed photocatalytic structures based on inorganic semiconductors. The photocatalytic mechanism was further investigated, showing that hydroxyl radicals (HO⦁) are the main radicals responsible for the degradation of organic pollutants. Besides, the reusability of the EBE-3D photocatalyst was demonstrated in up to 5 recycling uses. Overall, these results provide a great potential of a novel 3D-printed organic conjugated trimer for photocatalytic applications.