Unraveling the Mechanistic Origin of High N2 Selectivity in Ammonia Selective Catalytic Oxidation on CuO-Based Catalyst.
Environ Sci Technol
; 58(27): 12249-12259, 2024 Jul 09.
Article
in En
| MEDLINE
| ID: mdl-38935480
ABSTRACT
NH3 emissions from industrial sources and possibly future energy production constitute a threat to human health because of their toxicity and participation in PM2.5 formation. Ammonia selective catalytic oxidation to N2 (NH3-SCO) is a promising route for NH3 emission control, but the mechanistic origin of achieving high N2 selectivity remains elusive. Here we constructed a highly N2-selective CuO/TiO2 catalyst and proposed a CuOx dimer active site based on the observation of a quadratic dependence of NH3-SCO reaction rate on CuOx loading, ac-STEM, and ab initio thermodynamic analysis. Combining this with the identification of a critical N2H4 intermediate by in situ DRIFTS characterization, a comprehensive N2H4-mediated reaction pathway was proposed by DFT calculations. The high N2 selectivity originated from the preference for NH2 coupling to generate N2H4 over NH2 dehydrogenation on the CuOx dimer active site. This work could pave the way for the rational design of efficient NH3-SCO catalysts.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxidation-Reduction
/
Ammonia
Language:
En
Journal:
Environ Sci Technol
Year:
2024
Document type:
Article
Affiliation country:
China