Gas Phase and Surface Chemistry of Nitrogen in a Quartz Tube Using Vacuum Ultraviolet Single-Photon Ionization Time-of-Flight Mass Spectrometry (VUV-SPI-TOFMS)

Abstract

Chemical kinetic mechanisms of nitrogen compounds in combustion processes have been studied for many years. However, the models so far proposed have not been able to completely predict experimental results under some conditions in which surface reactions are expected to play an important role. Further investigation of a kinetic model for NO chemistry has been needed, and for this reason a kinetic model of nitrogen compounds both in a gas phase and on a quartz surface was developed in this study. The N/H/O mechanism developed by modifying earlier gas phase kinetic models was evaluated. However, the proposed mechanism was not able to reproduce the experimental results obtained from the vacuum ultraviolet single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS). The N/H/O mechanism including both gas phase reactions and surface reactions was proposed in this study. It is suggested that under the present experimental conditions the surface reactions on SiO₂ are effective for both NH₃ oxidation and NO chemistry based on model predictions that included both gas phase and surface reactions on SiO₂.