Efficient Photocatalytic Degradation of Textile Dyes Using Four-Element Doped Anatase Nanocrystals under...

An essential challenge in environmental catalysis is the development of efficient, visible‑light-active photocatalysts. In this study, we report the synthesis of seven anatase-phase nanocrystals doped with different dopants, including constant dopants of cerium (Ce), nitrogen (N), and and various alkali/alkaline‑earth metals.. Among the compositions studied, the strontium (Sr)-doped nanocrystal (NP-(Sr)) exhibits superior photocatalytic activity, completely degrading cationic, anionic, reactive, and azo textile dyes in less than 1 h under ultra-low-intensity light-emitting diode (LED) illumination (9.55 mW cm^-2). This achievement is attributed to lattice strain-induced surface activity, reduced crystallite size, and enhanced charge transport. The high active surface area obtained through anisotropic growth along the {001} plane by ethylenediamine results in a fast light response. The dominant role of superoxide radical generation and synergistic tuning of the band structure by Ce and N, confirmed by Mott-Schottky, cyclic voltammetry, photoluminescence, and electron paramagnetic resonance (EPR) spectroscopy, provided mechanistic insight into dye degradation. Furthermore, the localization of nitrogen within the bulk lattice and its high stability over multiple cycles demonstrate a scalable, low-energy solution for industrial wastewater treatment.