Photocatalytic properties of titanium oxide depend on the material size and shape, which can favour a higher interaction between reactants and catalyst. Most of the studies reported until now, show that reducing size down to the nanoscale increases the photocatalytic efficiency. We demonstrate that a multiscale shape design, integrating surface roughness, particle shape, and material 1D processing and orientation, can favour photocatalytic properties in the solid-gas regime, especially mineralization (conversion into CO2), when the material hierarchical 1D orientation is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone, and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design can favour high mineralization.