Development of α-Fe2O3/Nb2O5 photocatalysts by a Pechini sol–gel route: structural, morphological and optical influence

Recent researches involving the mixture of semiconductor oxides with different bandgap energies have shown to be an important alternative to obtain catalysts with better photocatalytic properties. In this study, mixed oxides of α-Fe2O3/Nb2O5 were prepared from a Pechini sol-gel route, with two different mass ratios of α-Fe2O3 and Nb2O5 and varying calcination temperatures. The influence of these parameters was investigated on the materials structural, morphological, optical and photocatalytic properties. Crystalline nanoparticles were obtained with significant differences in their properties and in the degradation efficiency of the methylene blue dye under UV–vis radiation. Calcination temperatures between 500 and 800 °C led to the formation of different crystalline phases, including: α-Fe2O3, Nb2O5, FeNbO4 and FeNb2O6; as well as the formation of materials with multigap behavior. High temperatures caused the increase of the particle size and the agglomerative state of the material. The catalysts produced have potential application for the treatment of effluents under solar radiation, in the presence or not of H2O2.