*2.2. Materials*

As a feedstock, we applied agglomerated TiO2 powder (TAYCA Corporation, WP0097, Osaka, Japan) containing a pure anatase crystalline structure with an average particle size of about 7.55 μm, as shown in Figure 1. The material chemical composition of substrates used is presented in Table 1.

**Figure 1.** SEM morphology of TiO2 powder.

**Table 1.** Material chemical composition [wt%].

