Nitrogen-containing TiO2 photocatalysts: Part 1. Synthesis and solid characterization

A series of N-substituted Ti isopropoxide precursors were synthesized by using three different amine-type ligands. The resulting Ti-complexes were characterized by nuclear magnetic resonance (NMR) and used to obtain solid precipitates by a reverse microemulsion method. These N-rich solid precipitates were subjected to three calcination treatments differing in the gas atmosphere allowed to contact the solid, yielding nanosized materials. A thermogravimetric analysis of the solid precipitates, combined with a mass spectrometry/infrared study of the evolving gaseous products, were able to show the influence of preparation parameters, e.g. Ti-precursor nature and treatment conditions, in the decomposition process of the solid precursors and the formation of the final nanoparticulated solid catalysts. Both parameters affect the interaction between solid oxygen species (O2−; OH−) and N,C-containing fragments present in the solid precursors. The chemical (e.g. nitrogen content), structural (phase, cell parameters and volume, and defect structure) and morphological (BET area and primary particle size) properties of the catalytic final solids were studied as a function of the preparation conditions.