Novel mixed metal oxide (ZnO•La2O3•CeO2) synthesized via hydrothermal and solution combustion process - A comparative study and their photocatalytic properties

Designing of novel semiconductor materials or enhance the potential of existing materials for the removal of the environmental pollutants is growing area of scientific interest. In this paper, novel binary ZnO center dot La2O3 (ZL) and ternary mixed metal oxides ZnO center dot La2O3 center dot CeO2 (ZLC) are synthesized using hydrothermal and solution combustion approach. The synthesized materials are characterized by the various techniques such as XRD, FESEM, UV-DRS and BET surface analyzer to uncover the structural, morphological and optical properties of the materials. The photocatalytic activity was evaluated by taking Rhodamine B dye as a model pollutant and 125 W mercury vapor lamp was used as light source. Despite the low crystallinity, hydrothermally synthesized samples possess better activity as compared to the solution combustion synthesized samples, which is attributed to their regular morphology and large surface area. The large surface area provide the more active sites and the regular morphology enhance the lifetime of the charge carriers by helping in migration of the photoinduced species. The hydrothermally synthesized sample showed 94.99% degradation of RhB on irradiation for about 160 min in basic medium. Experiments were performed using different scavengers to find the role of the active species in the degradation process. (C) 2019 Elsevier Ltd. All rights reserved.