Ni, Eu-Co doping effect on the photocatalytic activity and magnetic recyclability in multifunctional single-phase photocatalysts Bi₅FeTi₃O₁₅

Bi_5-yEu_yFe_1-xNi_xTi₃O₁₅ (x = 0, 0.05, 0.10, 0.15, 0.20; y = 0, 0.1, 0.3, 0.5) nanosheet-based nanoflowers as magnetic recyclable visible-light photocatalysts toward Rhodamine B (RhB) degradation were successfully synthesized by a hydrothermal method. As started from Bi₅FeTi₃O₁₅ (BFTO), Ni was firstly employed to substitute for Fe at B-site to improve the magnetism for magnetic recyclability. After Ni doping (Bi₅Fe_1-xNi_xTi₃O₁₅: BFNTO-x, x = 0, 0.05, 0.10, 0.15, 0.20), both the ferromagnetism and photocatalytic activity were obviously improved, where BFNTO-0.1 (Bi₅Fe_0.9Ni_0.1Ti₃O₁₅) exhibited the maximum remnant and statured magnetization of 0.14 and 0.82 emu/g respectively. To further improve the magnetism and photocatalytic activity, Eu was chosen to substitute for Bi at A-site. Both ferromagnetism and photocatalytic properties of Bi_5-yEu_yFe_0.9Ni_0.1Ti₃O₁₅ (BEFNTO-y, y = 0, 0.1, 0.3, 0.5) were further improved by optimizing the doped europium content. The BEFNTO-0.1 (Bi_4.9Eu_0.1Fe_0.9Ni_0.1Ti₃O₁₅) showed enhanced photocatalytic activity and could be recycled simply by applying a magnet bar. This work may provide a basis for further developing new visible-light photocatalysts because the layer-structured Aurivillius phase has significant potential in elemental doping and further structural engineering applications.