Abstract
Selective catalytic reduction (SCR) of NOx with NH3 by supported vanadium oxide catalysts is an important technology for reducing acidic NOx emissions from stationary sources and mobile diesel vehicles. However, rational design of improved catalysts is still hampered by a lack of consensus about reaction pathways and kinetics of this critical technology. The SCR fundamentals were resolved by applying multiple time-resolved in situ spectroscopies (ultraviolet-visible light (UV-vis), Raman and temperature-programmed surface reaction (TPSR)) and isotopically labeled molecules (18O2, H218O, 15N18O, ND3). This series of experiments directly revealed that the SCR reaction occurs at surface V5+O4 sites that are maintained in the oxidized state by O2 and the rate-determining step involves the reduction of V5+O4 sites by NO and NH3, specifically the breaking of N-H bonds during the course of formation or decomposition of the NO-NH3 intermediate.
| Original language | English |
|---|---|
| Pages (from-to) | 8358-8361 |
| Number of pages | 4 |
| Journal | ACS Catalysis |
| Volume | 7 |
| Issue number | 12 |
| DOIs | |
| State | Published - Dec 1 2017 |
Funding
The authors acknowledge financial support from the Center for Understanding & Control of Acid Gas-Induced Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by DOE, Office of Science, and Office of Basic Energy Sciences under Grant No. DE-SC0012577. Part of the work was conducted at the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, which is a DOE Office of Science User Facility. The authors would like to express their appreciation to Dr. Chris Keturakis (Cummins Emission Solutions) for many valuable comments.
Keywords
- NH
- NO
- SCR
- TPSR
- UV-vis
- spectroscopy
- vanadium oxide