One-pot synthesis of CeO2/Mg-Al layered double oxide nanosheets for efficient visible-light induced photo-reduction of Cr(VI)
2020
Wang, Fuhai | Liu, Xuezhu | Xu, Lan | Zheng, Xiaogang
CeO₂-modified Mg-Al layered double oxide (CeO₂/Mg-Al LDO) nanosheets were prepared via a one-pot hydrothermal route for visible-light induced photocatalytic reduction of Cr(VI). The addition of CeO₂ can enhance the visible light harvesting capacity and the separation of charge carriers of CeO₂/Mg-Al composites due to the surface-defect structures of Ce(III)/Ce(IV) couple and oxygen vacancies. The photocatalytic activity of CeO₂/Mg-Al is affected by CeO₂ content, Cr(VI) concentration, co-existing inorganic ions, and initial pH value. Among these obtained composites, CeO₂/Mg-Al-2 with a nominal Mg/Al molar ratio of 2:1 and CeO₂ content of 6.0 wt% presents the best photocatalytic efficiency and stability. The removal efficiency of Cr(VI) in the CeO₂/Mg-Al-2-assisted photocatalytic system is varied from 96.76% to 92.87% after five cycle times. The quenching behaviors of active species and the possible photocatalytic mechanism of CeO₂/Mg-Al-2 were proposed for the conversion of Cr(VI) into Cr(III) in the visible light region.
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