Characterization and Application of Pr-Co Codoped BiFeO₃ for Cr(VI) Reduction in the Process of Visible-Light...

The aim of the study was to apply a combined photothermal spectrometer that integrates BDS and PPE systems for multiparameter characterization of Pr-Co codoped BFO photocatalysts within a single measurement. Such a system provided information on the material's thermal diffusivity, conductivity, band gap, and carrier lifetime. The results indicate that moderate doping improves thermal transport and charge carrier separation, while excessive doping introduces additional recombination centers that accelerate charge carrier recombination and reduce heat propagation within the material. The photothermal measurements were supported by structural analysis of the samples performed by Powder X-ray Diffraction technique, Scanning Electron Microscopy coupled with Energy Dispersive X-ray Analysis, Fourier Transform Infrared Spectroscopy, and X-ray Photoelectron Spectroscopy. It was found that Pr-(III) and Co-(III) substituted into the BFO lattice without the formation of secondary phases and were accompanied by the reduction of crystallite size and morphological evolution. The photocatalytic performance of BFO materials was further verified in the reduction process of Cr-(VI) to Cr-(III) under natural environmental conditions using solar sunlight without the use of artificial light sources. This indicates that codoping significantly enhances Cr-(VI) reduction efficiency, achieving ∼96% within 120 min of the photocatalytic process. A correlation between structural, optical, and thermal parameters was also found, providing a basis for designing stable and efficient photocatalysts for environmental applications under solar sunlight.