Construction of Cu2+-doped CeO2 nanocrystals hierarchical hollow structure and its enhanced photocatalytic performance

Cu 2+ -doped CeO 2 @mSiO 2 (CDC@mSiO 2 ) samples with hollow structure were prepared by calcining Cu 2+ -doped cerium-based metal–organic framework (UiO-66 nanocrystals) precursor coated with mesoporous silica (mSiO 2 ). BET analysis shows that Cu 2+ -doped CeO 2 @mSiO 2 has a mesoporous structure and a large specific surface area (397.7 m 2 /g), which can provide more active sites for photocatalytic reactions. Ultraviolet absorption spectrum and PL spectrum show that the introduction of Cu 2+ makes the absorption edge of the sample red-shift and accelerate the electron–hole separation efficiency. Cu 2+ doping makes CeO 2 produce more oxygen vacancies, which promotes photocatalysis. The Cu 2+ -doped CeO 2 @mSiO 2 sample has the best photodegradation efficiency. Under simulated sunlight, the degradation rate of methyl orange within 2 h is 92.6%, and the photocatalytic rate constant is 0.0221/min. After 4 cycles of experiments, it still has excellent photocatalytic activity. Based on the characterization analysis and experimental results, the degradation mechanism of methyl orange is proposed.