Photocatalysis mediated removal of diclofenac potassium and energy storage efficiency of bismuth doped cerium tungstate

This work reports synthesis of bismuth doped cerium tungstate (Ce_2-xBi_x(WO₄)₃ where; x = 0.00, 0.01, 0.03, 0.05, 0.07, 0.09) followed by its optical, structural, and morphological characterization. X-ray diffraction analysis showed the presence of a single monoclinic phase together with successful bismuth doping. Scherrer's equation revealed a decrease in crystallite size from 28 nm (x = 0) to 13 nm (x = 0.05), followed by an increased crystallite size at x ≥ 0.07. BET surface area measurements revealed highest surface area (53.7 m²/g) of Ce_2-xBi_x(WO₄)₃ (x = 0.05) among all compositions greater than the surface area (3.5 m²/g) of undoped cerium tungstate. The photocatalytic potentials of as-synthesized materials against diclofenac potassium, were observed as follows: Ce₂(WO₄)₃ < Ce_1.91Bi_0.09(WO₄)₃ < Ce_1.93Bi_0.07(WO₄)₃ < Ce_1.99Bi_0.01(WO₄)₃ < Ce_1.97Bi_0.03(WO₄)₃ < Ce_1.95Bi_0.05(WO₄)₃. Under optimized conditions, the degradation efficiency of Ce_1.95Bi_0.05(WO₄)₃ reached up to 89.2 % in 120 min together with excellent reusability of the photocatalyst upon consecutive five runs, ensuring its effective usage for wastewater treatment. Among different compositions, the maximum dielectric constant (3.7075× 10⁵) was observed for Ce_1.95Bi_0.05(WO₄)₃, with a loss tangent of 0.494 at 20 Hz. In contrast, Ce_1.93Bi_0.07(WO₄)₃ and Ce_1.91Bi_0.09(WO₄)₃ exhibited relatively lower dielectric constants of 3.0499 × 10⁵ and 2.8444 × 10⁵, respectively, highlighting the importance of optimal dopant concentration for effective performance. These encouraging results suggest the multifunctional role of bismuth doped cerium tungstate in high frequency energy devices for efficient charge transmission as well as its effectiveness as a superb photocatalyst for removing persistent pollutants in water remediation.