Removal of NOx from air through cooperation of the TiO2 photocatalyst and urea on activated carbon fiber at room temperature

Removal of atmospheric NO to harmless N2 was successfully achieved through the continuous oxidation and reduction of NO into N2 using pitch-based activated carbon fiber (ACF), in which TiO2 and urea were co-supported. The combination of TiO2 and urea on the ACF gave high oxidation and reduction of NO. The TiO2 photocatalyst converted NO into NO2, which was immediately passed over urea on the ACF and reduced into harmless N2. Humidity seemed to accelerate the desorption of NO2 from the TiO2 surface, but did not affect the NO oxidation, indicating that humidity did not interfere with the reaction of NO into N2. The ACF system described is potentially very useful for the harmless removal of NO in the atmosphere near the roadside of urban area using natural wind effectively.

Graphical abstractNO conversion over TiO2–urea/ACF mixture under UV irradiation at 50% RH.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► NO was successfully removed into N2 with reactions with TiO2 and urea supported ACF. ► The produced NO2 on TiO2 was passed over urea to be continuously reduced into N2. ► Humidity accelerated NO2 desorption from TiO2, not interfering NO conversion into N2.