In:
Angewandte Chemie International Edition, Wiley, Vol. 58, No. 19 ( 2019-05-06), p. 6351-6356
Kurzfassung:
The unexpected phenomenon and mechanism of the alkali metal involved NH 3 selective catalysis are reported. Incorporation of K + (4.22 wt %) in the tunnels of α‐MnO 2 greatly improved its activity at low temperature (50–200 °C, 100 % conversion of NO x vs. 50.6 % conversion over pristine α‐MnO 2 at 150 °C). Experiment and theory demonstrated the atomic role of incorporated K + in α‐MnO 2 . Results showed that K + in the tunnels could form a stable coordination with eight nearby O atoms. The columbic interaction between the trapped K + and O atoms can rearrange the charge population of nearby Mn and O atoms, thus making the topmost five‐coordinated unsaturated Mn cations (Mn 5c , the Lewis acid sites) more positive. Therefore, the more positively charged Mn 5c can better chemically adsorb and activate the NH 3 molecules compared with its pristine counterpart, which is crucial for subsequent reactions.
Materialart:
Online-Ressource
ISSN:
1433-7851
,
1521-3773
DOI:
10.1002/anie.201901771
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2019
ZDB Id:
2011836-3
ZDB Id:
123227-7