Visible Light Active 0.95KNbO₃‐0.05Ba(Nb_1/2Sc_1/2)O₃ Ferroelectric for Enhanced Photocatalytic Activity

Abstract This study reports a visible light active Ba/Sc co‐doped potassium niobate (KNbO₃) ferroelectric material for enhanced photocatalytic applications. Through 5% Ba and Sc co‐doping in KNbO₃ (i.e., 0.95KNbO₃‐0.05Ba(Nb_1/2Sc_1/2)O₃), the electronic band gap (E_g) is narrowed down to the visible range of the solar spectrum. The prepared samples are systematically examined by using X‐ray diffraction and Raman spectroscopy, which confirms the successful incorporation of Ba and Sc ions into the KNbO₃ lattice. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis reveal particle morphology and chemical homogeneity of prepared samples. The UV–vis spectroscopy and ferroelectric PE‐loop demonstrate enhanced optical absorption compared to host KNbO₃ while retaining ferroelectric behavior. The photoelectrochemical (PEC) measurements under visible light irradiation demonstrate a notable enhancement in the photocurrent for 0.95KNbO₃‐0.05Ba(Nb_1/2Sc_1/2)O₃ (hereafter denoted by 5KBSNO) compared to undoped KNbO₃. Additionally, the 5KBSNO sample displays enhanced RhB dye degradation efficiency, reaching ≈50% compared to parent KNbO₃ (≈30%) under light irradiation. First‐principles density functional theory (DFT) calculations are employed to understand the mechanism responsible for the reduced band gap. This study presents a promising material for developing advanced ferroelectric photocatalysts with tailored band structures for efficient solar energy harvesting for energy conversion and contamination remediation applications.