NO Oxidation Using H<sub>2</sub>O<sub>2</sub> at a Single-Atom Iron Catalyst
Weijie Yang, Liugang Chen, Binghui Zhou, Zhenhe Jia, Xiaoshuo Liu, Yanfeng Liu, Hao Li, Zhengyang Gao
Abstract
Nitrogen oxide (NO) is a major worldwide environmental pollutant, which can be eliminated effectively by catalytic oxidation. However, conventional catalysts generally suffer from poor activity and low oxidation rates, limiting the development of gas pollutant removal. To overcome this issue, the high activity of a single-atom catalyst and the strong oxidizability of H 2 O 2 are proposed for the catalytic oxidation of NO in this work. Herein, the 14 reaction pathways of NO oxidation using H 2 O 2 were obtained through spin-polarized density functional theory calculation with van der Waals corrections and microkinetic modeling. Considering the possible H 2 O 2 activation products of *OH, *OOH, and *O, we obtained the dominant reaction pathways for different oxidizing species: (i) Langmuir–Hinshelwood mechanism of *OH (mainly forming *HNO 2 ), (ii) Eley–Rideal mechanism of *O (forming *NO 2 ), and (iii) *OOH (forming *HNO 3 ), with the energy barriers of 0.94, 1.42, and 0.14 eV, respectively. Among the three reaction patterns, NO oxidation using *OOH is the most favorable, with the highest reaction rate. *HNO 3 is the most likely oxidation product of NO oxidation using H 2 O 2 . Meanwhile, it is notable that the *OH catalytic oxidation of NO has multiple reaction pathways and products, including HNO 2, NO 2, and HNO 3 . Compared to the use of conventional oxidants and catalysts, using H 2 O 2 to oxidize NO at Fe–N 4 –C catalyst has lower reaction energy barriers and allows for the deep oxidation of NO. This study illustrates the reaction pathway of NO oxidation using H 2 O 2 and demonstrates that it is theoretically feasible, which provides guidance for the subsequent preparation of the material.