TiO2-Doped Fe-Tailings Heterogeneous Catalysts: Engineering Synergistic Photocatalytic-Fenton Pathways for High-Efficiency Phenol Mineralization

Phenol, as a representative organic pollutant in industrial wastewater, poses a critical challenge for environmental remediation. In this study, titanium-doped iron tailings-based heterogeneous catalysts (Ti/PCG) with enhanced electron transfer kinetics were synthesized via a high-temperature sintering method and evaluated for their photo-Fenton degradation efficiency toward phenol. The Ti/PCG catalysts were systematically characterized via SEM, BET, XPS, and photoelectrochemical analyses to elucidate their structural and electronic properties. Results indicated that 15% TiO 2 -doped Ti/PCG exhibited optimal properties, including the largest specific surface area, well-developed hierarchical pore structures, superior charge transfer capacity, and high carrier separation efficiency. Under optimized conditions (pH = 2.75, 0.2 ml H 2 O 2 (30 wt%), and 1 h light irradiation), the 15% Ti/PCG achieved 80.68% removal of phenol (initial concentration: 100 ppm). Mott-Schottky and VB-XPS analyses confirmed the n-type semiconductor behavior of the 15% Ti/PCG, with a conduction band (E CB ) at − 0.455 eV and a valence band (E VB ) at 2.09 eV, enabling the proposal of a plausible photo-Fenton degradation mechanism. Radical trapping experiments further demonstrated that hydroxyl radicals (·OH) and superoxide radicals (·O 2 − ) dominated the phenol degradation process. This work provides an optimized photo-Fenton strategy for phenol-laden wastewater treatment with 80.68% degradation efficiency, while demonstrating the potential of industrial solid wastes as sustainable catalysts in environmental remediation.