Novel Method for Preparing Controllable Nanoporous α-Fe_2O_3 and its Reactivity to SCR De-NO_x

10.4209/aaqr.2017.05.0188

Haibo Liu；Zexin Zhang；Qian Li；Tianhu Chen；Changai Zhang；Dong Chen；Chengzhu Zhu；Yang Jiang

α-FeOOH ； Controllable nanoporous α-Fe_2O_3 ； Selective catalytic reduction ； Mechanism

Aerosol and Air Quality Research

17卷7期（2017 / 07 / 01）

1898 - 1908

英文

Controllable nanoporous hematite (CNH, α-Fe_2O_3) was prepared by thermal treatment of α-FeOOH at different temperatures, and the SCR activity of the prepared α-Fe_2O_3 was evaluated. XRD (X-ray diffraction), HRTEM (highresolution transmission electron microscopy), N_2 adsorption-desorption, XPS (X-ray photoelectron spectroscopy), and NH_3-TPD (NH_3-temperature programmed desorption) were utilized to characterize the catalysts. The results indicated that after thermal treatment at less than 600°C, the α-Fe_2O_3 catalysts exhibited excellent NO conversion that was higher than 80% in a temperature range from 300 to 400°C. CNH400 with a relatively large surface area of 47.24 m^2 g^(-1) and many surface hydroxyl groups did not exhibit a substantially improved SCR activity even though it exhibited the best SCR activity. Therefore, the L-H mechanism was not the main reaction route for SCR of NO by α-Fe_2O_3. The increasing crystallization of α-Fe_2O_3 decreased the SCR activity, indicating that a decrease in surface oxygen defects was important for the SCR of NO and fitting the E-R mechanism. The NH_3-TPD and XPS (O1s) results confirmed this hypothesis. This study provides an approach for the design and preparation of a controllable nanoporous α-Fe_2O_3 catalyst for SCR of NO by NH_3.