Removal of low concentration nitrogen oxides through photoassisted heterogeneous catalysis

Article abstract of DOI:10.1016/0304-5102(93)E0247-E

Titanium dioxide (Tio²) oxidized nitric oxide (NO) to nitric acid (HNO₃) very rapidly under ultraviolet light illumination, but some NO was oxidized to nitrogen dioxide (NO₂), while activated carbon (AC) adsorbed NO₂ well. A mixture of TiO₂ and AC was thus confirmed to be an excellent photoassisted catalyst for removal of low concentration (sub-ppm) NO_x from air. Addition of 1-3 wt % of ferric oxide to the mixture could markedly increase the catalytic activity. Even though the catalytic activity gradually declined with the reaction time, it could be completely recovery only by washing the catalyst was removed.