Visible Light Active 0.95KNbO3-0.05Ba(Nb1/2Sc1/2)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.