Single-Atom Cu-Doped TiO2 nanorods with modulated surface active sites for superior photocatalytic performance

Single-atom Cu is recently certified as an ideal metal dopant to improve the photocatalytic performance of TiO2, whereas related work is lacking to understand the correlation between the surface electronic property of the single-atom Cu-TiO2 and its photocatalytic mechanism. Herein, using the H2Ti3O7 nanowire as the precursor, the Cu-doped TiO2 nanorod (Cu1-TiO2) is prepared via a simple and in-situ strategy including the Cu+-exchange and high-temperature calcination. It is found that Cu single atoms successfully incorporate into the lattice of TiO2 via occupying Ti vacancies, and the Cu1-TiO2 maintains the well-defined crystal structure of anatase. The doping Cu single atoms are theoretically simulated to induce three new states inside the bandgap of TiO2, and increase its separation efficiency of photoinduced carriers and the absorption efficiency for the visible light. Meanwhile, all O atoms around the Cu atom exhibit a weaker electron-captured ability than ones close to Ti atom, making the single-atom Cu center a strong adsorption site for the tetracycline (TC) molecule. Both the reformative band structure and the optimized adsorption behavior jointly endow the Cu1-TiO2 with a superior photocatalytic performance for the TC degradation under the irradiation of visible light. The achieved fundamental understanding of the correlation between the catalyst surface electronic property and the photocatalytic performance would provide guidelines to design more single atom photocatalysts for the possible practical applications.