Multiple layers, porous surface, and their role in increasing the efficiency of photocatalytic coating on (DD3, DD3+ZrO₂) ceramics and glass

Magnesium-doped zinc oxide thin films were dip-coated onto porous ceramic and glass substrates under identical conditions (50 layers, same doping ratio). Structural, morphological, and photocatalytic properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), UV–visible spectrophotometry, and confocal microscopy. XRD analysis indicated a shift in peak positions towards higher angles, increased grain size, and lattice distortion on both substrates. Unique flower-shaped crystalline granulates were observed exclusively on the ceramic substrate (DD3Z). The energy gap decreased on the ceramic and increased on the glass substrate. The photocatalytic activity was evaluated using an aqueous orange II solution, showing significantly higher decomposition (80 ± 0.53 % after 6 h) on the ceramic compared to the glass substrate (30 %). The enhanced performance on ceramic substrates, particularly with DD3+ZrO₂, was attributed to increased microporosity, surface roughness, and active material incorporation, facilitating greater photocatalytic efficiency. The findings suggest promising applications of these materials for efficient and cost-effective photocatalysis, with potential for reuse after thermal treatment at 500 °C.