Hydrothermal synthesis of Sr-doped α-Bi2O3 nanosheets as highly efficient photocatalysts under visible light

• One-step synthesis of Sr doped α-Bi2O3 nanosheets-like was achieved.
• The prepared sample Bi2O3 and Sr/Bi2O3 crystallographic phase is monoclinic form.
• Sr/Bi2O3 with regular and highly dense nanosheets were formed.
• 7.5% Sr doped Bi2O3 nanosheets showed 15 times higher activity than α-Bi2O3.
• Sr doped α-Bi2O3 nanosheets are superior to that of undoped α-Bi2O3.

In this contribution, we report a facile synthesis of Sr doped α-Bi2O3 nanosheets-like at different Sr content (0–10 wt%). The XRD results indicated that the phase of undoped α-Bi2O3 and Sr/α-Bi2O3 nanosheets are monoclinic α-Bi2O3 form and it easily nucleates during hydrothermal method at low temperature and short reaction time. FE-SEM images revealed that α-Bi2O3 was smooth plate-like as it consisted plenty of well-defined plates with a side length of 200–500 nm and a thickness of about 25 ± 5 nm. However, regular and highly dense Sr/α-Bi2O3 nanosheets were formed after Sr addition. The band gaps of the α-Bi2O3 and %Sr doped α-Bi2O3 at different Sr content 1, 2.5, 5, 7.5 and 10% are 2.86, 2.85, 2.84, 2.75 and 2.81 eV respectively. The photocatalytic properties of the prepared samples were evaluated by degradation of methylene blue under visible light. The photocatalytic activity significantly enhanced with increasing Sr doping levels with a plateau at 0–7.5% Sr, then gradually decreased at 10% Sr. The results indicated that 7.5% Sr doped α-Bi2O3 nanosheets is 15 times higher photoactivity than undoped α-Bi2O3. Overall, this work could provide new insights into the fabrication of Sr doped α-Bi2O3 nanosheets as high performance photocatalysts under visible light and facilitate their application in the environmental protection issues.

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