Origin of enhanced photocatalytic activity of F-doped CeO₂ nanocubes

Graphical abstract: - Highlights: • F-doped CeO₂ nanocubes with higher percentage of reactive facets exposed is synthesized. • F-doping in CeO₂ results in the narrowing of band gap. • F-doped CeO₂ nanocubes exhibit high photocatalytic activities. - Abstract: CeO₂ nanoparticles are synthesized using a low-temperature solution combustion method and subsequent heat treatment in air. It is found that F-doping leads to smaller particle size and the formation of CeO₂ nanocubes with higher percentage of reactive facets exposed. The band gap is estimated to be 3.16 eV and 2.88 eV, for pure CeO₂ and fluorine doped CeO₂ (F-doped CeO₂) nanocubes, respectively. The synthesized F-doped CeO₂ nanocubes exhibit much higher photocatalytic activities than commercial TiO₂ and spherical CeO₂ for the degradation of MB dye under UV and visible light irradiation. The apparent reaction rate constant k of MB decomposition over the optimized F-doped CeO₂ nanocubes is 9.5 times higher than that of pure CeO₂ and 2.2 times higher than that of commercial TiO₂. The enhanced photocatalytic activity of F-doped CeO₂ nanocubes originates from the fact that F-doping induces the small size, the highly reactive facets exposed, the intense absorption in the UV–vis range and the narrowing of the band gap. This research provides some new insights for the synthesis of the doping of the foreign atoms into photocatalyst with controlled morphology and enhanced photocatalytic activity.