Ecofriendly Synthesis and Multifunctional Energy Applications of Ca-Doped Bi₂O₃ Nanoparticles

This study presents a novel green synthesis of undoped and Ca-doped Bi 2 O 3 nanomaterials using celery extract via a sol-gel method. Varying Ca-dopant concentrations (1 mol%, 3[Formula: see text]mol%, 5[Formula: see text]mol% and 7[Formula: see text]mol%) influenced the average crystalline size, increasing from 42.11[Formula: see text]nm to 70.3[Formula: see text]nm with increasing dopant levels. FTIR studies revealed the functional groups. A notable band gap reduction from 2.36[Formula: see text]eV to 2.24[Formula: see text]eV indicated successful band gap tuning through Ca doping. The synthesized nanomaterials exhibited a unique flower-like morphology, confirmed by HR-TEM analysis, with a crystalline size of approximately 70[Formula: see text]nm. Electrochemical studies, conducted using a three-electrode system in 1 M KCl electrolyte, demonstrated excellent specific capacitance performance in cyclic voltammetry and galvanostatic charge–discharge measurements. The 7[Formula: see text]mol% Ca-doped Bi 2 O 3 sample exhibited superior stability. Furthermore, CB7 displayed remarkable performance in the green remediation of Acid Green-25 dye, achieving significantly higher degradation compared to the undoped material. This research highlights the potential of celery-mediated green synthesis for producing high-performance, eco-friendly Bi 2 O 3 nanomaterials for electrochemical and environmental applications.