Follow-up mechanism study on NO oxidation with vaporized H2O2 catalyzed by Fe2O3 in a fixed-bed reactor

Abstract

Nitric oxide (NO) oxidation with vaporized hydrogen peroxide (H2O2) catalyzed by hematite (Fe2O3) is conducted in a fixed-bed reactor. The XPS characterization of fresh and spent catalyst implies that the catalytic decomposition of H2O2 over the catalyst surface follows the Haber-Weiss mechanism. Studies on gas products and liquid products are carried out under different operation conditions. The experimental results show that the conversion of NO into NO2 or HNO3 with vaporized H2O2 is significantly promoted by Fe2O3 at low catalytic temperatures. Among the temperature range of 80 °C–300 °C, the NO conversion achieves the highest at ca. 180 °C and subsequently, decreases with the catalytic temperature increased. The reaction rate of NO oxidation is obtained in a fixed-bed reactor and is modeled with four typical gas-solid catalytic kinetic models. According to the calculation results, the H2O2-adsorbed Eley-Rideal model gives the best fit among the four kinetic models. Finally, a possible reaction mechanism for NO oxidation with vaporized H2O2 catalyzed by Fe2O3 is proposed.