Investigation of the band gap energy shift and photocatalytic properties of Bi³⁺-doped ceria

A series of Bi³⁺-doped CeO₂ photocatalysts have been prepared using simple coprecipitation method. The effect of Bi³⁺ doping on structural surface morphology and optical properties of the prepared photocatalysts was characterized using diffuse reflectance spectroscopy (DRS), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) for determination of the specific surface area and porosity. All prepared photocatalysts exhibit fluorite-type structure with no phase change up to 10 mol percent Bi³⁺ doping when calcinated at 973 K for 1 h. A red shift in optical band gap measurements was observed with increasing Bi³⁺ ion percent doping. Photocatalytic performance of prepared photocatalysts were examined using visible-light-induced photocatalytic reduction of 4-nitroaniline to p-phenylenediamine. The highest photocatalytic efficiency was achieved using CeO₂ photocatalyst with 5 mol percent Bi³⁺ doping.