This equation showed that potential peak Ep is linear

The thickness of the coatings produced by the PEO treatment of titanium surface in silicate electrolyte reaches 10 μm. The elemental composition analysis of coatings showed presence (at.%) 70.9-O, 15.6-Si, 13.1-Ti and 0.4-Na. According to XRD of the oxide layer scraped off from a titanium substrate (Fig. 1a), the coatings include titanium oxide in structural modifications of rutile and anatase. None of the diffraction patterns show reflections from crystallized siliceous phases. According to previous investigation [22] silicon SB2343 present in the coating in the form of the amorphous silica. The typical surface of a titanium plate after PEO treatment (Fig. 2a) is rough: there are raised textures, hollows, and pores, which may be the traces of electric breakdowns or the outlets for gas bubbles. The oxide film consists of the crystallites with the size of 3–10 μm, and uniformly covers the surface of the titanium, with a pores diameter reaching 5–7 μm. The morphology of prepared composition CuMoO4/TiO2 + SiO2/Ti is demonstrated in Fig. 3. After impregnation with Cu and Mo and calcination at 550 °С the surface of the PEO coating is covered by agglomerated grains with size up to 10–12 μm. The elemental composition analysis of fertilization particles determined a ratio of metals corresponding to the CuMoO4 phase. The amount of supported catalyst was ~ 1.6 wt.%.