Low-temperature sol–gel synthesis of crystalline CoTiO3 coatings without annealing

The present work reports a new approach for a low-temperature synthesis of CoTiO3 based on titanium isopropylate hydrolysis in the presence of cobalt pyrochroite dispersed nanoparticles. This allowed to carry out the synthesis of the material at near-room temperatures without heat treatment stage. It is found that ilmenite phase formation occurs upon partial dehydration of the [Co(OH2)6]2+ complex to yield a mono- or a di-aqua complex ([Co(OH2)](OH)2; [Co(OH2)2](OH)2). An analysis of composition of formed materials depending on stoichiometric ratios of components is performed using X-ray diffraction and thermal analyses. Using thermal analysis data, an investigation on the effect of formed prestructure and composition of materials on ilmenite crystallization temperature is carried out. Possible ways of chemical interaction are presented. Using atomic force microscopy, the morphology of products formed in the course of synthesis and fixed on the surface of heat-unstable materials is studied.

► The CoTiO3 films have been obtained for the first time without heat treatment under usual conditions. ► Study of interface CoO–TiO2 NPs reaction for composite formation. ► Create a new low-temperature sol–gel synthesis of nanosized ilmenite(Co) crystals, without heat treatment. ► The effect of stoichiometric ratios of components on CoTiO3 crystallization is studied. ► Possible chemical transformations are represented by schemes.