Enhanced photocatalytic degradation of Bisphenol A under visible light by Cr-TiO2 nanoparticles

[Display omitted] •The sol–gel method was used to synthesize Cr-TiO2 nanoparticles.•The Cr-TiO2 samples showed greater surface area and a reduction in crystallite size.•The samples presented aggregate morphology with an average size of 7.2 nm.•1CrTi exhibited the highest photocatalytic activity under visible irradiation at 240 min.•The photodegradation is mainly carried out by hydroxyl and superoxide radicals. In this study, Cr-TiO2 nanoparticles were synthesized using the sol–gel method, with TiO2 photocatalyst doped varying Cr concentration. The photocatalysts were assessed for their efficacy in degrading Bisphenol-A under visible light (40 W, 3000 lm, and λ = 400–700 nm, with two maximum peaks at 450 and 545 nm). Optical, morphological, and structural characterization were conducted. TiO2 doped with 1 % Cr exhibited a remarkable 99 % reduction in BPA degradation within 4 h, compared to the 51.5 % degradation observed with bare TiO2. This enhancement can be attributed to synergistic effects arising from increased surface area, reduced particle size, and the semi-spherical, uniform morphology of the nanoparticles. Photoluminescence analysis revealed that Cr ion incorporation slowed the recombination processes between photogenerated electron/hole pairs. XPS and Eg data facilitated the calculation of VB and CB values, indicating that the photocatalysts predominantly oxidize the BPA molecule through superoxide (O2∙-) and hydroxyl (HO∙) radicals.