Efficient Conversion of NO2 into N2 and O2 in N2 or into N2O5 in Air by 172-nm Xe2 Excimer Lamp at Atmospheric Pressure

Abstract

Decomposition of NO2 (200 ppm) in N2 or air by 172-nm Xe2 excimer lamp was studied at 1 atm. The NO2 conversion in N2 was 99%, and the formation ratios of N2, O2, NO, and N2O were 47, 98, 0, and 2%, respectively, after 30 min irradiation. The NO2 in air (5–20% O2) could be completely converted to N2O5 and HNO3 due to reactions by O3 and H2O after only 1.0–1.5 min irradiation. The present results give a new simple photochemical aftertreatment technique of NO2 in air without using any catalysts.

Photochemical Removal of SO2 and CO2 by 172 nm Xe2 and 146 nm Kr2 Excimer Lamps in N2 or Air at Atmospheric Pressure

“…Among these reactions, two-body reaction (17) and threebody recombination reactions ( 12) and ( 19) are more significant than reactions (18) and (20), because the rate constant of reaction ( 18) is very small and the relative concentration of CO 2 is lower than those of N 2 and O 2 .…”

“…It was applied to the photochemical removal of NO and NO 2 in N 2 or air in our previous studies. [18][19][20] In this study, we investigated the photochemical removal of SO 2 and CO 2 using a 172 nm Xe 2 excimer lamp. In addition, we also used a 146 nm Kr 2 excimer lamp as a new VUV source for the removal of these molecules.…”

25 W of average power at 172 nm in the vacuum ultraviolet from flat, efficient lamps driven by interlaced arrays of microcavity plasmas

“…Although the Xe 2 molecular lamp (λ = 172 nm) is the most efficient emitter available in the VUV, intensities generated by commercially-available lamps are generally restricted to 30-50 mW cm 2 , and their cylindrical geometry is not amenable to the spatially uniform irradiance of a surface. [4][5][6][7][8] To briefly summarize the status of source development in the 100-250 nm region, the dearth of inexpensive and compact, but powerful, lamps and lasers has impeded the progress of VUV photonics and its applications (such as photochemistry, photopolymerization, water purification, and surface physics).…”

Photochemical Removal of N2O in N2 or Air Using 172 nm Excimer Lamps

“…We have recently initiated the photochemical removal of NO x using a 193 nm ArF excimer laser and a 172 nm Xe 2 excimer lamp without using any expensive catalysts. [15][16][17][18][19][20][21] An advantage of photochemical methods is that N 2 is inert for photoirradiation at 193 and 172 nm. Therefore, NO emission due to the decomposition of N 2 is negligible.…”