Noble-Metal-Free NO_<i>x</i> Storage over Ba-Modified TiO₂ Photocatalysts under UV-Light Irradiation at Low Temperatures

Abstract

Photoassisted nitrogen oxide (NO_<i>x</i>) storage was investigated over the barium-modified titanium dioxide (Ba/TiO₂) photocatalysts under UV-light irradiation at a high concentration of nitrogen monoxide (NO) of 200 ppm and a high gas hourly space velocity (GHSV) of 50 000 h^–1. The NO removal efficiency was kept >99% during the 1020 s interval from the start of the reaction over the Ba/TiO₂ photocatalyst. The temperature-programed desorption (TPD) measurement and X-ray diffraction (XRD) technique revealed that barium oxide (BaO) species functioned as a NO_<i>x</i> storage material even at low temperatures, which result in improvement of the performance of the photoassisted NO_<i>x</i> storage