Highly stable 3D multilayered nanoparticles-based β-Bi2O3 hierarchitecture with enhanced photocatalytic activity

beta-Bi2O3 is defined as the most photoactive among various Bi2O3 polymorphs. However, it revealed poor stability under photocatalytic environment. Herein, by adding bismuth oxide formate (HCOOBiO, BiOR) to bismuth citrate with premium molar ratio of 1:3 followed by air calcining at 350 degrees C, the nanosheet-based quasi-spherical beta-Bi2O3 (Bi2O3-sp) converted into nanoparticle-based multilayered sheet-like 3D hierarchitecture (Bi2O3-ml), which exhibited greatly enhanced photocatalytic activity under visible light irradiation from 58.2% to 98% for malachite green (MG) and 67.8% to 92.9% for tetracycline (TC) degradation. The enhanced photodegradation efficiency of Bi2O3-ml could be ascribed to improved visible light absorption and higher BET surface area. Furthermore, Bi2O3-ml under photocatalytic environment revealed high durability and photochemical stability, which was discussed in detail for the first time. The PL spectra of the recycled Bi2O3-ml revealed slight increase in the quantum efficiency of photocatalytic system after four runs. A possible reaction mechanism was also proposed.