Doping-induced enhancement of dual functionality of cerium tungstate for dielectric and photocatalytic applications

Diclofenac potassium, a nonsteroidal anti-inflammatory drug (NSAID) has emerged as a contaminant of serious concern. Hence, an effective strategy is crucial regarding designing of a photocatalyst to remove this complex pharmaceutical with a purpose of environmental remediation. In the present work, cerium tungstate doped with different concentrations of antimony, Ce_2-xSb_x(WO₄)₃ (0.00 ≤ x ≤ 0.09), has been synthesized by a simple co-precipitation method and subsequently, evaluated for its optical, structural, and morphological properties. Among different doped compositions, the higher value of the dielectric constant of Ce_1.93Sb_0.07(WO₄)₃ (3.6233 ×10⁵) than Ce₂(WO₄)₃ (2.4762 ×10⁵), indicates its ability to effectively store charges. The photocatalytic removal of the diclofenac potassium by Ce_1.93Sb_0.07(WO₄)₃ (88.6 %) was highest when compared with the pristine cerium tungstate (68.4 %). Moreover, Ce_1.93Sb_0.07(WO₄)₃ showed impeccable stability over five consecutive photocatalytic cycles with excellent fit to pseudo-first order kinetics. The influence of doping was evidenced by rate constant of cerium tungstate which increased by 1.83 times indicating the faster degradation ability of Ce_1.93Sb_0.07(WO₄)₃. The smaller charge transfer resistant (R_CT) of Ce_1.93Sb_0.07(WO₄)₃ (87.4 Ω) than pristine cerium tungstate (141.7 Ω) also facilitated easy migration of charge carriers for superb photocatalytic action. This work established the potential applicability of Ce_1.93Sb_0.07(WO₄)₃ towards charge storage applications as well as photocatalytic removal of diclofenac potassium.