The development of Fe2O3-based catalysts used for the selective catalytic reduction of NO with NH3: A review

The emission of nitrogen oxides (NOx) from the coal-fired power plants poses a huge threat to human health and natural environment. The selective catalytic reduction of NOx with NH3 (SCR) has been proven to be a mature technology for the abatement of NOx. To be the crucial component, the performance of the catalysts plays a determined role during the deNOx process. Fe2O3-based catalysts, as one of the most effective catalysts for SCR, have been comprehensively researched and fruitful results are achieved. Therefore, the advances in the applications of Fe2O3-based catalysts for NOx reduction was overviewed in this work. Simply put, the fundamentals of Fe2O3, such as this metal oxide's crystal structures and the corresponding preparation methods, were first introduced. After that, the physicochemical features and deNOx performances of various catalysts, including virgin Fe2O3, Fe2O3-supported, and Fe2O3-containing mixed oxide systems, were summarized. Considering the variable flue gas conditions in coal-fired power plants, the effects of the typical components of SO2, HCl, H2O, and fly ash on the catalyst's NOx reduction activity were also evaluated and the results demonstrated that with proper modification, catalyst flue gas component adaptability could be availably improved. Furthermore, the possible NOx reduction pathways over the Fe2O3-based catalysts under various conditions were discussed with the key intermediates and the rate-controlling stages clarified. Finally, suggestions were raised that attention needed to be concentrated on developing new Fe2O3-based catalysts that was capable of stably operating in real coal-fired flue gas in following research.