Critical assessment of a Ce-doped SnO₂ loaded on PPSAC composite photocatalyst on improved photocatalytic activity under visible light

The photodegradation of organic dye by Ce-doped SnO₂-loaded Pongamia pinnata shell-activated carbon (Ce:SnO₂/PPSAC) is investigated in this study. Pure SnO₂, Ce-doped SnO₂ and loaded samples were synthesized using a chemical precipitation technique. The all-product samples were characterized by XRD, XPS, FE-SEM with EDS, FTIR, UV-Vis, PL and EIS analysis. XRD pattern showed that the average crystallite size is reducing (14.19 nm) upon Ce-doping and PPSAC-loading sample compared to the pure SnO₂. The band gap decreases (3.47 eV) upon Ce-doping and loading on PPSAC compared to SnO₂. Moreover, the separation of the photogenerated charge carriers was improved by the Ce:SnO₂/PPSAC, which decreases PL emission intensity. The photocatalytic activity for rhodamine B (RhB) degradation under visible light was investigated. The photodegradation efficiency of Ce:SnO₂/PPSAC was found to be 98.94% under 105 min, which was greater than the other samples. The features developed in Ce-doped and loaded PPSAC contribute to the improved photocatalytic activity of Ce:SnO₂/PPSAC by reducing the band gap, inhibiting electron-hole recombination, and improving the charge separation of photogenerated carriers. A possible photocatalytic mechanism for the decomposition of RhB was proposed. This study shows that Ce:SnO₂/PPSAC is a potentially promising material for wastewater treatment.