Gas-phase flow-through photocatalysis using wirelessly anodized WO3 nanoporous layers on Tungsten 3D meshes produced by extrusion-based additive manufacturing

• First demonstration of 3D W meshes for gas-phase flow-through photocatalysis. • 3D W meshes were fabricated via extrusion-based additive manufacturing. • Nanoporous WO 3 layers were formed on their surfaces via wireless anodization. • Nanoporous WO 3 layers enhanced surface area and provided viable W 6+ /W 5+ species. • Effective photocatalytic acetaldehyde degradation was achieved in the flow-regime. Herein, hierarchically porous 3D W meshes were fabricated via extrusion-based additive manufacturing, using commercially pure W powder as feedstock. These mechanically robust structures exhibit high porosity and an effective surface area of approximately 60 cm 2 , making them highly promising for gas-phase photocatalysis. Wireless anodization via bipolar electrochemistry was successfully applied to form nanoporous WO 3 layers on the 3D meshes, for the first time. These meshes were then employed for photocatalytic acetaldehyde degradation in a flow-through reactor designed according to ISO standards. Compared with thermally grown WO 3 layers on identical 3D W meshes, the nanoporous WO 3 layers showed superior performance due to their larger surface area, achieving ∼7% acetaldehyde conversion and a mineralization rate of ∼93%, indicating that nearly all removed acetaldehyde was fully mineralized. These findings highlight the potential of anodized 3D W meshes for innovative applications in flow-through photocatalytic reactors.