Influence of 3D architecture on photocatalytic efficiency in structures derived from a novel boron acrylate via UV-SLA and pyrolysis

Additive manufacturing enables the fabrication of photocatalytic three-dimensional architectures with precisely controlled geometry, offering new opportunities to optimize light and material interaction, structural stability, and catalyst reusability for water-treatment applications. In this work, monolithic 3D photocatalysts were fabricated by UV stereolithography using a newly synthesized boron and nitrogen-containing acrylate photoresin, followed by high-temperature pyrolysis to obtain polymer-derived ceramic structures. The chemical structure of the photoresin was confirmed by 1 H NMR spectroscopy, while refractive index measurements demonstrated its suitability for stereolithography. Thermal analysis revealed a multistep polymer-to-ceramic conversion with significant mass loss and densification, accompanied by pronounced geometry-dependent volumetric shrinkage during pyrolysis. Phase transformation monitored by X-ray diffraction showed a transition to the hexagonal boron nitride phase after high-temperature treatment. A range of architected geometries, including channel, lattice, and gyroid-based cubic and rounded models, were evaluated to assess the influence of 3D architecture on photocatalytic behavior. Photocatalytic activity was investigated via Rhodamine B degradation under halogen lamp irradiation. Structures annealed at 500 ° C and 900 ° C exhibited limited activity, whereas samples treated at 1200 ° C showed a marked increase in performance despite reduced surface area caused by shrinkage. When normalized to photocatalyst surface area, curved gyroid-type architectures outperformed channel and lattice designs, reaching a maximum specific degradation efficiency of 355.01 mg/m 2 . These results demonstrate that the photocatalytic response is governed by the combined effects of the composition of the material and three-dimensional architectural model.