Investigation of the band gap and photocatalytic properties of CeO2/rGO composites

[Display omitted] •Compared to pure ceria, the wavelength of CeO2/rGO composites exhibited a red shift upon increasing the mass % of rGO added.•Pure CeO2 and CeO2/rGO photocatalysts were prepared using coprecipitation method.•Pure CeO2 and CeO2/rGO photocatalysts were tested for the photocatalytic reduction of 4-NA.•PXRD patterns for the prepared pure and rGO composites showed pure cube phase of CeO2.•All prepared photocatalysts exhibited significant activity toward the photoreduction of 4-NAto PPD. CeO2 and CeO2/rGO composites photocatalysts has been prepared using simple coprecipitation method. The effect of rGO 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) and Brunauer-Emmett-Teller for determination of the specific surface area/ porosity (BET). All prepared photocatalysts exhibits fluorite-type structure with no phase change up to 5 wt percent rGO when calcinated at 700 °C for 1 h. A red shift in optical band gap measurements was observed with increasing rGO percent. 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 wt percent rGO.