Effect of oxygen vacancies on improving NO oxidation over CeO2 {111} and {100} facets for fast SCR reaction

Effects of different exposed crystal surfaces of CeO2 loaded on an MnO2/X catalyst for the NH3-SCR reaction

“…Furthermore, zeolite X as a support for Mn–Ce oxide showed better low-temperature NH 3 -SCR performance than that of ZSM-5 and beta. Also, in our other studies, 26,27 CeO 2 had different exposed crystal surfaces and the denitration performance of them was different. However, pure CeO 2 as a catalyst exhibited some shortcomings, such as poor low-temperature activity and thermal stability.…”

“…It is well known that the presence of Ce 3+ leads to the formation of unsaturated chemical bonds and further promotes the formation of more oxygen vacancies. 26,39 Oxygen vacancies are conducive to the oxidation of NO to NO 2 and the generation of more surface chemisorbed oxygen, which facilitate “fast SCR” reactions. 40,41 The sequence of the ratio of Ce 3+ to total Ce was Mn–Ce NR /X (19.73%) > Mn–Ce NC /X (16.63%) > Mn–Ce NP /X (12.94%), which was inconsistent with the de-NO x activity.…”

“…A hydrothermal method was used to prepare CeO 2 with different exposed crystal surfaces, the preparation details of which were shown in our previous work. 26,27 For the CeO 2 nanocube catalyst (CeO 2 -NC), the required quantities of Ce(NO 3 ) 3 ·6H 2 O and NaOH were dissolved in deionized water. Afterwards, NaOH solution was added dropwise into the Ce(NO 3 ) 3 solution under magnetic stirring at room temperature.…”

Green and Moderate Activation of Coal Fly Ash and Its Application in Selective Catalytic Reduction of NO with NH3

“…Meanwhile, in comparison with 3V/ACFA, numerous Fe-containing components were exposed over 3V/MC-CFA, due to the damage of the vitreous shells with the collision of grinding balls. In addition to the standard NH 3 –SCR reaction, the fast-SCR reaction was found to be crucial for NO reduction, especially when Fe-based catalysts such as Fe-exchanged zeolites were used. − This indicated that the Fe-containing components could also improve the catalytic activity of 3V/MC-CFA. Therefore, owing to the interaction of V species and Fe components, the efficiencies of NO conversion over the 3V/MC-CFA catalyst were promoted in the range of 250 to 375 °C, as shown in Figure a.…”

Recent advances in hydrothermal synthesis of facet-controlled CeO2-based nanomaterials

“…76 The generation and elimination of oxygen vacancies in CeO 2 are directly accompanied by the release and storage of oxygen, 77 mainly determined by the type, size, and distribution of surface defect oxygen vacancies. 78 In addition, the change in oxygen vacancy concentration is dependent on particle size.…”