Flow-through Gas Phase Photocatalysis Using TiO₂ Nanotubes on Wirelessly Anodized 3D-Printed TiNb Meshes

In this work, for the first time 3D Ti-Nb meshes of differentcomposition,i.e., Ti, Ti-1Nb, Ti-5Nb, and Ti-10 Nb, were produced by direct inkwriting. This additive manufacturing method allows tuning of the meshcomposition by simple blending of pure Ti and Nb powders. The 3D meshesare extremely robust with a high compressive strength, giving potentialuse in photocatalytic flow-through systems. After successful wirelessanodization of the 3D meshes toward Nb-doped TiO2 nanotube(TNT) layers using bipolar electrochemistry, they were employed forthe first time for photocatalytic degradation of acetaldehyde in aflow-through reactor built based on ISO standards. Nb-doped TNT layerswith low concentrations of Nb show superior photocatalytic performancecompared with nondoped TNT layers due to the lower amount of recombinationsurface centers. High concentrations of Nb lead to an increased numberof recombination centers within the TNT layers and reduce the photocatalyticdegradation rates.