Akademik Veri Yönetim Sistemi
Ceramics International, cilt.52, sa.4, ss.5031-5049, 2026 (SCI-Expanded, Scopus)
Plasma electrolytic oxidation (PEO) was employed to fabricate porous ceramic layers on a brass substrate in an aluminate-based electrolyte. The influence of subsequent heat treatment on structure–property relationships was investigated in relation to visible-light photodegradation of methylene blue (MB). Annealing at 425 °C balanced nanostructure formation and microcrack control, while reducing water contact angle to 11.6° (from ∼29°), enhancing hydrophilicity. Grazing incidence X-ray diffraction (XRD) revealed ZnO, CuO, and CuAlO2 phases alongside substrate peaks; X-ray photoelectron spectroscopy (XPS) confirmed Cu2+species and Al 2p signals consistent with CuAlO2. Optical measurements showed a direct band gap of ∼2.86 eV, and Mott–Schottky analysis indicated predominantly n-type behavior with junction features consistent with embedded p-type CuO. The sample annealed at 425 °C for 2 h (holding time had no significant effect) was identified as optimal, achieving 54 % MB removal at 15 ppm under visible light—13 % higher than the as-prepared coating. Activation of peroxymonosulfate (PMS) produced a clear synergy (synergy factor ≈ 2.57), significantly boosting MB abatement. Matrix ion tests revealed nuanced effects: PO43−and Cl−enhanced removal (63 % and 57 %), while NO3−suppressed it (∼44 %). Reuse tests showed ∼13 % drop after the second cycle, followed by stable performance over four cycles. Scavenger experiments identified the roles of reactive oxygen species and clarified the underlying photocatalytic mechanisms. Based on detected intermediates, a plausible degradation pathway for MB was proposed. Overall, heat treatment (425 °C/2 h) optimizes morphology, wettability, and junction-assisted charge separation in ZnO/CuO/CuAlO2 PEO coatings, enabling robust visible-light photocatalysis.