Removal of NOX Using Hydrogen Peroxide Vapor over Fe/TiO2 Catalysts and an Absorption Technique

In this study, we proposed an innovative oxidation–absorption method for low-temperature denitrification (160–240 ◦C), in which NO is initially catalytically oxidized by hydrogen peroxide (H2O2) vapor over titania-based catalysts, and the oxidation products are then absorbed by NaOH solution. The effects of flue gas temperature, molar H2O2/NO ratio, gas hourly space velocity (GHSV), and Fe substitution amounts of Fe/TiO2 catalysts on the denitrification efficiency were investigated by a well-designed experiment. The results indicated that the Fe/TiO2 catalyst exhibited a combination of remarkable activity and deep oxidation ability (NO converted into harmless NO3). In order to comprehend the functional mechanism of the Fe dopant’s local environment in TiO2 support, the promotional effect of the calcination temperature of Fe/TiO2 on the denitration performance was also studied. A tentative synergetic mechanism could be interpreted from two aspects: (1) Fe3+ as a substitute of Ti4+, leading to the formation of enriched oxygen vacancies at the surface, could significantly improve the adsorption efficiency of •OH; (2) the isolated surface Fe ion holds a strong adsorption affinity for NO, such that the adsorbed NO could be easily oxidized by the pre-formed •OH. This process offers a promising alternative for current denitrification technology.