Enhanced ME–Piezo–Photocatalysis in Electrospun Sm‐Doped BiFeO ₃ Nanofibers via Nanoconfined Lattice Distortion

ABSTRACT

Single‐phase multiferroic BiFeO ₃ exhibits antiferromagnetism and weak magnetoelectric (ME) coupling due to its cycloidal spin structure (period ≈ 62 nm), which fundamentally limits its ME–piezo–photocatalytic activity. Herein, we demonstrate that Sm doping in (Bi _1−x Sm _x )FeO ₃ ( x  = 0–0.2) induces lattice‒distortion coupling that disrupts the spin cycloid and releases latent magnetization, leading to Sm‐doping‐dependent modulation of multiferroicity, ME coupling, and optical properties, with optimal piezo–photocatalysis ( x  = 0.15). This lattice‒distortion coupling is further nanoconfined within the one‐dimensional boundaries of the nanoporous hollow (Bi _0.85 Sm _0.15 )FeO ₃ ceramic nanofibers (NFs) fabricated by sol‒gel‒electrospinning. The resulting fibers provide abundant catalytic sites, enhanced ferro/piezoelectricity, and a narrowed band gap (2.02 eV), achieving an ME–piezo–photocatalytic rate constant of 2.7 × 10 ⁻² min ⁻¹ . Cyclic tests yield rate constants of 1.77 ± 0.17, 0.84 ± 0.48, and 2.97 ± 0.59 × 10 ⁻² min ⁻¹ , after excluding the outlier, the mean value is 2.50 × 10 ⁻² min ⁻¹ (RSD = 24.8%). Combined with the morphological and microstructural observations, these results confirm the good stability and reusability. The synergistic enhancement originates from ferroelectric and ME vibration‐induced built‐in electric fields that effectively suppress photogenerated electron–hole recombination. This study demonstrates that lattice‒distortion coupling in rare‐earth‐doped BiFeO ₃ NFs provides a promising strategy for enhancing ME–piezo–phototronics in environmental remediation.