Effect of adsorption properties of phosphorus-doped TiO2 nanotubes on photocatalytic NO removal.

A series of P doped TiO2 nanotubes (P-TNTs) catalysts were prepared for photocatalytic oxidation (PCO) of NO. Compared with TiO2 nanotubes, P-TNTs catalysts exhibited excellent catalytic activity. We confirmed that P was doped into TiO2 nanotubes lattice by XRD, Raman and TEM characterization. It was found that the enhanced PCO performance of NO was not attributed to the photoelectric properties of the P-TiO2 from UV-vis, Mott-Schottky and transient photocurrent response results. Therefore, we focused on the studies of catalyst reaction process and reactant adsorption characteristics. The results of transient reactions showed that the catalytic reaction proceeded via a mixed mechanism of Langmuir-Hinshelwood (L-H) and Eley-Rideal (E-R) on the P-TiO2 catalyst. In addition, P doping was beneficial to the adsorption of H2O2 and NO, which is ascribed to the improved PCO performance of NO.