Synthesis of binary metal doped CeO2 via the subcritical hydrothermal method for photo-mineralizing methyl orange dye

Abstract

Herein, we adopted subcritical hydrothermal method to synthesize the copper and bismuth co-doped CeO2 (Ce0.92Cu0.04Bi0.04O2) nanostructure for water remediation application. Copper and Bismuth co-doping synergistically improved the current conductivity and light-harvesting capabilities of the co-doped CeO2 that is respectively confirmed through current-voltage and optical studies. The microstructural, compositional and morphological information of the as-synthesized photocatalyst were accessed through powder XRD, and electronics spectroscopic techniques. In terms of practical application, the as-prepared co-doped CeO2-based photocatalyst mineralized the anionic dye (methyl orange, MO) up to 95.79%, at the rate of 0.0314 min−1, in just 50 min of solar irradiation. Statistics show that our Ce0.92Cu0.04Bi0.04O2 photocatalyst is 2.32 times more effective at mineralizing MO dye, and its rate of dye mineralization is 5.5 times faster than a CeO2 photocatalyst. In addition, the Ce0.92Cu0.04Bi0.04O2 photocatalyst possesses exceptional robustness as it fully retains its photocatalytic activity after three consecutive reusability tests. Our doped photocatalyst's excellent dye mineralizing activities come from the way its hybrid nanostructure morphology, good current conductivity, visible-light-supported bandgap, and induced structural defects work together. This gives it a larger surface area, a faster charge transport rate, better light harvesting ability, and lower charge recombination efficiencies. The copper and bismuth co-doping in the CeO2 lattice have a positive effect on its photocatalytic properties, suggesting that it has the potential to be a light-driven catalyst for azo dyes degradation.