Enhanced photocatalytic degradation efficiency of flexible carbon cloth-based TiO2/CdS/NiO multi-composite heterojunctions via electron-beam evaporation

To address the limitations of traditional chemical methods and powder catalysts in photocatalysis, this study reports a novel physical vapor deposition (PVD) approach for constructing efficient and recyclable heterojunctions. Using electron-beam evaporation, the amorphous NiO film was deposited onto the surface of chemically synthesized TiO 2 /CdS precursors, ultimately yielding the flexible TiO 2 /CdS/NiO (TCN) multi-composite photocatalyst. The light absorption, charge carrier behavior, and degradation mechanism were investigated through UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), photoelectrochemical testing, and free radical trapping experiments. The prepared TCN composite material achieved a degradation efficiency of 96% for methyl orange (MO) within 60 min of visible-light irradiation, significantly outperforming pure TiO 2 (17%) and TiO 2 /CdS (41%). It also demonstrates broad-spectrum degradation capabilities for multiple antibiotics and exhibits excellent cycling stability. Mechanistic analysis indicates that both a Type-II heterojunction (TiO 2 /CdS) and a p-n heterojunction (CdS/NiO) are formed within the material. The built-in electric fields in both junctions are aligned, thereby synergistically promoting the efficient separation and migration of photogenerated electron-hole pairs. This work provides a new technical pathway and theoretical basis for designing practical, easily recyclable and highly efficient photocatalytic materials that minimize secondary pollution.