Synthesis, characterization and immobilization of N-doped TiO2 catalysts by a reformed polymeric precursor method

Abstract

A novel synthetic method to prepare N-doped TiO2 catalysts was studied, by which a stable and homogeneous liquid polymeric precursor was produced, thus the catalysts can be loaded on suitable substrates, making catalysts facilely separated from waste water. The doping ratios and annealing temperatures were optimized by testing photodegradation of the products to methyl orange. To improve the Brunauer-Emmett-Teller surface areas of the catalyst, PEG was grafted to the structure of precursor polymer, by which an increase of 55% in BET surface areas and 20% in the photodegradation efficiencies was achieved. The crystalline phase was measured by X-ray diffraction and structural parameters were calculated by Xpert Highscores. FESEM and HRTEM pictures showed that the average particle size of the nitrogen doped and PEG modified catalyst reached to only 5 nm. X-ray photoelectron spectroscopy showed that nitrogen dope mode was interstitial. Using quartz fabrics as substrate, the loaded catalysts were facilely recycled and reused by 15 times without decay in photodegradation efficiency.