Unraveling the structure and role of Mn and Ce for NOx reduction in application-relevant catalysts.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35618799.
- Also identified by DOI 10.1038/s41467-022-30679-9 and PMC identifier 9135741.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Mn-based oxides are promising for the selective catalytic reduction (SCR) of NOx with NH3 at temperatures below 200 °C. There is a general agreement that combining Mn with another metal oxide, such as CeOx improves catalytic activity. However, to date, there is an unsettling debate on the effect of Ce. To solve this, here we have systematically investigated a large number of catalysts. Our results show that, at low-temperature, the intrinsic SCR activity of the Mn active sites is not positively affected by Ce species in intimate contact. To confirm our findings, activities reported in literature were surface-area normalized and the analysis do not support an increase in activity by Ce addition. Therefore, we can unequivocally conclude that the beneficial effect of Ce is textural. Besides, addition of Ce suppresses second-step oxidation reactions and thus N2O formation by structurally diluting MnOx. Therefore, Ce is still an interesting catalyst additive.