Multi-functional fluorinated NiTiO₃ perovskites for CO₂ photocatalytic reduction, electrocatalytic water splitting, and biomedical waste management

Multi-functional F-doped NiTiO₃ structures with high stability were prepared by a template-free hydrothermal method. A multi-technique approach including several physicochemical techniques was employed to describe the morphology, electronic properties, and structural characters. The F-doped NiTiO₃ catalyst showed a much higher CO₂ to CH₄ photocatalytic conversion rate (2.6 μmol g⁻¹ h⁻¹) than pristine NiTiO₃ (1.6 μmol g⁻¹ h⁻¹), highlighting the key role of F impurities in suppressing the charge carriers recombination. In addition to the higher efficiency and reusability than Pt/C reference electrode toward electrocatalytic water splitting, a lower Tafel slope was recorded for the F-doped structure (81.2 mV dec⁻¹). This implies significant improvement in the reaction kinetics, arising from the synergistic effects between the F sites and bulk constituents to supply more desired active electronic states. The capability of the structures for the biomedical wastewater (containing the Caco-2 cancer cells) treatment was also explored. According to several biochemical assays, the fluorinated material shows a promising performance against the tumor cells at its IC50 concentration, 0.15 μg/mL, in a typical hospital wastewater. Our results pave the way for developing novel multi-functional photoactive titanate perovskites aiming at future clean energy transition.