Photocatalytic Activity Improvement Studies For Bismuth Oxide And Bismuth Oxycarbonate

Photocatalysis has emerged as a promising technique owing to its valuable applications in environmental purification. The preparation of high efficient visible light responsed photocatalysts has attracted more and more attentions. In this work, Cu2O-modified Bi2O3 nanospheres and Er-doped Bi2O2CO3 microspheres with perfect visible-light catalytic activity were successfully synthesized. The obtained products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) Brunauer-Emmett-Teller (BET) surface area, UV-visible diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and X-ray fluorescence spectroscopy (XRF). The photocatalytic activities were evaluated by degradation of Rhodamine B (RhB).The prepared Cu2O-modified Bi2O3 nanospheres exhibited enhanced photocatalytic activity in the degradation of RhB. Cu2O was dispersed on the surface of Bi2O3 nanospheres. All of Cu2O-modified Bi2O3 nanospheres showed uniformly nanospheres with the size of 80-150 nm. Cu2O modification increased the BET surface area, narrowed band gap, and enlarged the light absorption region. The possible photocatalysis mechanism was the interfacial charge transfer process. This process accelerated the separation of photo-induced electron and holes, which leaded to the higher efficiency of photocatalysis.The prepared Er-doped Bi2O2CO3 microspheres also showed enhanced photocatalytic activity in the degradation of RhB. In the prepared samples, Bi3+ was substituted by Er3+, which induced the decrease of lattice spacing. The higher BET surface area, the band gap narrowing and the broadened light absorption region was also caused by the doping of Er3+. In the photocatalysis, the host Bi2O2CO3 could use visible light directly by virtue of the upconversion luminescent Er3+ to generate holes and electrons in the VB and CB, respectively.