Structural and optical tuning of BiVO₄ via cerium doping for enhanced dye degradation performance

Abstract Nanomaterials with advanced functionalities offer immense potential for environmental remediation by accelerating pollutant degradation and promoting sustainable purification methods. This study presents the synthesis of lanthanide cerium (Ce)-doped BiVO₄ via a cost-effective co-precipitation approach, followed by a comprehensive evaluation of its structural, morphological, and optical characteristics. X-ray diffraction (XRD) analysis confirmed the monoclinic phase of BiVO₄. The calculated average crystallite sizes for pristine and Ce-doped BiVO₄ were 51.3 nm and 43 nm, respectively, indicating a reduction due to Ce incorporation. Fourier Transform Infrared (FTIR) spectroscopy further validated the successful doping through noticeable peak shifts in the vibrational spectra. The surface morphology and elemental composition of the synthesized catalysts were analyzed using Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX) spectroscopy.The optical properties, examined through UV-Vis Diffuse Reflectance Spectroscopy (UV-DRS), exhibited a redshift in the absorption edge, enhancing visible light responsiveness. Tauc’s plot analysis demonstrated a reduction in band gap energy from 2.54 eV (pristine) to 2.3 eV (Ce-doped BiVO₄), indicating improved light-harvesting efficiency. Photoluminescence (PL) spectroscopy revealed suppressed charge carrier recombination, both contributing to superior photocatalytic performance. The photocatalytic activity was assessed by degrading Methylene Blue (MB), a model cationic dye, under varying experimental conditions. The Ce-doped BiVO₄ exhibited an exceptional degradation efficiency of 98% within 1 hr of solar irradiation, which is approximately 25% higher than pristine BiVO₄. Furthermore, its recyclability was demonstrated over six successive cycles, with minimal reduction in degradation efficiency, confirming its stability.The narrower band gap, enhanced visible light absorption, reduced charge carrier recombination, and outstanding stability establish Ce-doped BiVO₄ as a highly promising catalyst for wastewater treatment and environmental sustainability. Graphical Abstract