Crystal phase transition of β-Bi2O3 and its enhanced photocatalytic activities for tetracycline hydrochloride

Abstract The crystal phase has an important effect on the photocatalytic activity of Bi2O3. However, due to the high recombination of photo-induced charge carriers in single crystal phase Bi2O3, the photocatalytic activity was still unsatisfied. Herein, we prepared a novel α/β-Bi2O3 hetero-phase junction (xB) by a simple solvothermal-calcination method, the photocatalyst was well characterized by XRD, SEM, TEM, UV–vis DRS, XPS, photoelectrochemical technology, etc. The characterizations indicated that the crystal phase of Bi2O3 gradually transformed from β phase to α phase as the calcination temperature increased, and the Bi2O3 of different crystal phases were in close contact with a clear interface. With the optimum calcination temperature at 400 ℃, 400B sample showed the highest photocatalytic activity for tetracycline hydrochloride (TC-HCl) degradation, 91.4% removal within 120 min, the kinetic rate (0.0188 min−1) was 3.2 and 3.1 times higher than that of β-Bi2O3 (0.0058 min−1) and α-Bi2O3 (0.0061 min−1), respectively. This work provides an ideal strategy to synthesize hetero-phase junction photocatalysts with the crystal phase transition of semiconductors.