Enhanced Photocatalytic Degradation by the Preparation of a Stable La-Doped FeTiO3 Photocatalyst: Experimental and DFT Study

The rapid photocarrier recombination limits the photocatalytic activity of iron titanate (FeTiO₃) to be further improved. Developing novel approaches to inhibit the rapid recombination rate of the FeTiO₃ photocatalysts is crucial for efficiently degrading pollutants in wastewater. Rare earth ions, with unique electron dispositions and large ion radii, could effectively inhibit photocarrier recombination. Herein, novel lanthanum (La)-doped FeTiO₃ photocatalysts were designed and successfully synthesized. The photocatalytic performance of the 12 mol % La/FeTiO₃ photocatalyst was superior in degrading tetracycline hydrochloride (TCH), methylene blue (MB), and brilliant blue (BB). These degradation rate constants (k) were 0.12358, 0.01357, and 0.03064 L mg^-1 min^-1, respectively, which were 12.83, 1.61, and 7.78 times that of pure FeTiO₃. The photoelectronic tests and density functional theory (DFT) calculations revealed that the La 4f orbital forms an impurity energy level in the conduction band of FeTiO₃. This level narrows the bandgap and acts as an electron acceptor, capturing photoexcited electrons and inhibiting the rapid recombination of photoexcited electron-hole pairs in FeTiO₃. This work enhances the potential of FeTiO₃ in the photocatalysis field and provides important insights into the efficient degradation of organic pollutants in wastewater.