Enhanced Photocatalytic Activity and Ferromagnetism in Gd Doped BiFeO₃ Nanoparticles

BiFeO3 (BFO) is of considerable interest because of its potential applications in the design of devices combining magnetic, electronic, and optical functionalities. Effects of the Gd dopant on the structural, photocatalytic activity, and ferromagnetic properties of BFO nanoparticles have been studied. X-ray diffraction and Raman spectra results of Bi1−xGdxFeO3 (BGFOx, x = 0, 0.05, 0.1, and 0.15) reflect that the crystal structure of the samples remain stable for x < 0.1, while compositional-driven phase transition from rhombohedral to orthorhombic is observed at x = 0.1. The photocatalytic activity to decompose Rhodamine-B under visible-light illumination increases in BGFOx as x increases from zero to 0.1 and then decreases for x = 0.15. The maximum in photocatalytic activity near the phase boundary of x = 0.1 is associated with the changing of the polar behavior of the nanoparticles. Comparing with the linear magnetization−magnetic field (M−H) relation in pure BFO nanoparticles, obvious M−H loops can be observed in the doped samples, which are ascribed to the distorted spin cycloid and magnetically active characteristic of Gd3+ ions.