Synergistically engineered TiO2-based porous ceramics via ZnO-doped and NaBH4 reduction for enhanced visible-light photocatalytic degradation of methylene blue

Despite extensive research on TiO₂-based photocatalysts, their poor visible-light response and low charge-separation efficiency still limit practical applications in wastewater treatment. While previous studies have explored individual strategies such as metal doping or defect engineering, few have systematically investigated their synergistic effects in TiO₂ porous ceramics. This study addresses these challenges by developing a dual-modification strategy combining ZnO doping and NaBH₄ reduction to enhance the photocatalytic performance of TiO₂ porous ceramics. ZnO doping promotes anatase phase stability and inhibits the anatase-to-rutile transition, while NaBH₄ reduction introduces abundant oxygen vacancies and Ti³⁺ species, narrowing the band gap and extending light absorption into the visible range. As a result, the optimized ceramics achieve a methylene blue degradation efficiency of 90.07 %, outperforming undoped (79.32 %) and singly ZnO-doped (86.01 %) counterparts. This synergistic enhancement is attributed to the tailored surface chemistry and electronic structure, verified through structural and optical characterizations. Compared with previous TiO₂ porous ceramic studies, this work provides a scalable and effective modification strategy, offering new insights for designing high-efficiency, recyclable photocatalysts for environmental remediation.