Synthesis of Bi2O3 nanomaterials with different crystal structures (α-, β- and γ-phase) based on calcined Bi2O2CO3 and their potential applications in photocatalysis and acetone gas sensors

In this work, using flower-like Bi 2 O 2 CO 3 as the precursor, by changing the calcination temperature and cooling rate, we successfully synthesized α-, β-, and γ-Bi 2 O 3 nanomaterials . Photocatalytic experiments were performed on these bismuth-based semiconductors separately. The results showed that β-Bi 2 O 3 exhibits higher photocatalytic activity than other bismuth-based oxides (α-, γ-Bi 2 O 3 ) under visible light . The degradation efficiency of β-Bi 2 O 3 for four kinds of organic dyes is: Methylene Blue (94.10 %, 120 min), Rhodamine B (85.30 %, 120 min), Methyl Orange (92.59 %, 120 min) and Congo Red (96.97 %, 120 min). Meanwhile, gas sensor based β-Bi 2 O 3 exhibit well acetone gas response, such as low detection limit (below 5 ppm in 250 ℃), short response/recovery time (<1 s /9 s), selectivity to acetone and excellent reproducibility. Compared to previous other works, all these performances have been significantly improved due to its narrow bandgap (2.58 eV) and unique morphology of β-Bi 2 O 3 . All these advantages indicate that β-Bi 2 O 3 nanomaterials has great potential in the field of photocatalysis and acetone gas sensors. • Flower-like Bi 2 O 2 CO 3 precursor used to synthesize α-, β-, and γ-Bi 2 O 3 nanomaterials . • β-Bi 2 O 3 exhibits excellent acetone response (5 ppm, < 1 s / 9 s recovery), good reproducibility. • Photocatalytic degradation properties have been improved significantly compared with other Bi 2 O 3 .