Tunable photocatalytic and magnetic properties in Y and transition metals (TM = Mn, Co, Ni, Cu, Zn) co-doped BiFeO₃: DFT + U study

The magnetic and optical properties of Y and transition metals (TM = Mn, Co, Ni, Cu, Zn) co-doped BiFeO3 (BFO) are studied through first principles calculations. The (Y + TM)-codoping produces obvious improved magnetization, and the (Y + Mn)-BFO, (Y + Ni)-BFO and (Y + Zn)-BFO systems exhibit strong ferromagnetism with total magnetic moments of 3.97 mu(B), 3.97 mu(B), and 5.09 mu(B) per supercell, respectively. The calculated band gaps of all co-doped configurations are further narrowed compared with that of Y mono-doped BFO, indicating that (Y + TM)-codoping extends the optical absorption edge to the visible light region. The (Y + Cu)-BFO shows the minimum band gap due to the impurity bands locate in the mid-gap. The prediction photocatalytic activities are in order of (Y + TM)-BFO> Y-BFO> BFO, indicating that Y and TM co-doping can significantly enhance the catalytic performance, which is consistent with the results in experiment. Especially, the (Y + Mn)-BFO display excellent catalytic performance among them, revealing that Mn doping provides an efficiency strategy for improved ferromagnetic and optical properties in Y-BFO.