Review on Catalytic Oxidation of NO by Gas-phase Oxidants

As NO_x emission standards become stringent, development of cost-effective NO_x control technologies becomes urgent. In addition to selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR), oxidation method has received much attention recently because this method makes it possible to simultaneously remove NO_x and SO₂ from flue gas via wet scrubbing. This study reviews catalytic oxidation of NO by O₂, catalytic oxidation of NO by ClO₂, catalytic oxidation of NO by O₃, and catalytic oxidation of NO by plasma, respectively. Additionally, the catalysts with their application and advantages/disadvantages commonly used in catalytic oxidation of NO, and molar ratio of O₃/NO, gas residence time, reaction temperature, other components in flue gas which may affect catalytic deep oxidation of NO are summarized. Finally, the recommendations for prospective research on catalytic oxidation of NO are proposed. The review on catalytic oxidation of NO by gas-phase oxidants provides new ideas for future studies on removal of NO from flue gas streams and NO catalytic deep oxidation by ozone may be a viable technology to meet strict NO_x emission standard.