Synthesis of β-Bi2O3 towards the application of photocatalytic degradation of methyl orange and its instability

Bismuth oxide carbonate was synthesized from bismuth nitrate and potassium carbonate and then converted to phase pure beta-Bi2O3 form by means of thermal decomposition. X-ray diffraction, HR-SEM, diffuse reflectance UV-vis and photocatalytic degradation studies were carried out on both the samples. Bi2O2CO3 exhibited a wide band gap of 3.406(5) eV while beta-Bi2O3 had a lesser band gap of 2.589(3) eV. beta-Bi2O3 degrades a higher amount of methyl orange because of its lesser band gap and its optimum loading was 0.1 g in 50 ml of 10 ppm solution. After photocatalytic degradation Bi2O2CO3 remains in the stable form whereas beta-Bi2O3 changes to Bi2O2CO3. (C) 2015 Elsevier Ltd. All rights reserved.