Catalytic performance of calcined Fe2O3/CA catalyst for NH3-SCR reaction: Role of activation temperature

With the purpose of developing an environment-friendly and high-efficiency catalyst for the selective catalytic reduction of nitrogen oxides (NOx) by ammonia (NH3-SCR), citric acid (CA)-decorated Fe2O3 (Fe2O3/CA) was synthesized via a simple water bath method and followed by calcination activation. The catalytic performance showed that the catalyst activity was closely related to the calcination temperature. When the calcination temperature was 300 ​°C, the as-synthesized catalyst displayed the best NH3-SCR activity, and extraordinary N2 and N2O selectivity in a wide range of operating temperatures. Subsequently, the crystal phase, morphology, physical features, chemical states, redox properties, and surface acidity properties of the as-synthesized catalysts were investigated by various characterization techniques. The results demonstrated that Fe2O3/CA calcined at a suitable temperature could promote the speciation transformation of the partial phase from α-Fe2O3 to γ-Fe2O3. In addition, appropriate calcination of Fe2O3/CA could also improve the reducibility and increase the number of acid sites. All of these factors, collectively, accounted for the excellent NH3-SCR activities of the catalyst. © 2022 Elsevier Inc.