<p>Inadequacy of visible light response due to the wide bandgap yield confines the practical application of CeO₂ for breakdown harmful pollutants in wastewater treatment. This research work presents the photocatalytic degradation of pure and nanoporous carbon–doped CeO₂ (C-CeO₂) nanocrystal for the degradation of ofloxacin antibiotic triggered by visible light irradiation. The effect of nanoporous C dopant on the structural, morphological, and optical properties was studied using various spectroscopy techniques. The X-ray diffraction (XRD) analysis confirm the cubic structure of both samples, further indicating the average crystalline size of the synthesized C-CeO₂ is nearly 21&#xa0;nm comparatively lower than pure CeO₂ (28&#xa0;nm). Transmission electron microscopy (TEM) analysis shows the formation of nanocrystals of CeO₂ on the nanoporous carbon surface along with less agglomeration. The optical band gap of CeO₂ and C-CeO₂, estimated with the help of Tauc equation, is 3.1 to 2.6&#xa0;eV, respectively, suggesting C-CeO₂ are capable of acting as a photocatalyst under visible light irradiation. The degradation efficiency of ofloxacin is 98% for C-CeO₂ nanostructure, which perform much better than CeO₂ in 80&#xa0;min of light irradiation. The photoluminescence (PL) studies show the higher concentration of oxygen vacancies on the surface of C-CeO₂ thus resulting enhancement of the photocatalytic activity. Electrochemical impedance spectra (EIS) analysis confirmed the C-CeO₂ nanostructure has faster separation of charge carrier than pure CeO₂. Compared with pure CeO₂, C-doped CeO₂ nanostructure enhanced photocatalytic activity for ofloxacin degradation.</p>