Ti3+-TiO2/Ce3+-CeO2 Nanosheet heterojunctions as efficient visible-light-driven photocatalysts

Highlights: • A novel Ti³⁺-TiO₂/Ce³⁺-CeO₂ nanosheet heterojunction is fabricated. • It owns the bandgap of 2.6 eV and extends the photoresponse to visible light region. • It exhibits excellent visible-light-driven photocatalytic performance. • It is due to synergy of Ti³⁺, Ce³⁺ co-doping and nanosheet heterojunction. - Abstract: Novel Ti³⁺-TiO₂/Ce³⁺-CeO₂ nanosheet heterojunctions are successfully prepared via a facile hydrothermal approach combined with a wet-chemical deposition precipitation and an in situ solid-state chemical reduction strategy. The structures of the as-prepared samples are characterized in detail by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and UV–vis diffuse reflectance spectroscopy. The results show that Ti³⁺ and Ce³⁺ are both doped into the lattice of TiO₂ and CeO₂, respectively, which narrow the band gap to 2.7 eV and extend the photoresponse to visible light region. The photocatalytic degradation rate of methyl orange and methylene blue are as high as 93.3% and 97.1% under visible-light illumination, respectively. The high degradation rate is attributed to the efficient doping of Ti³⁺ and Ce³⁺, formation of surface oxygen vacancy and heterojunction, which favors the absorption of visible light and separation of photogenerated charge carriers.