The Role of H+- and Cu+-Sites for N2O Formation during NH3-SCR over Cu-CHA
Artikel i vetenskaplig tidskrift, 2021

The mechanism for N2O formation over CHA and Cu-CHA zeolite catalysts during NH3-SCR is investigated using density functional theory calculations. Direct NH4NO3 decomposition, which is commonly regarded as the main source of N2O, is found to be associated with high barriers in the absence of Brønsted acid sites. Although Brønsted acid sites promote NH4NO3 decomposition, it is still a highly activated process. Low-temperature N2O formation is instead found to be connected with an NO + NH3 reaction over Cu-sites. In particular, N2O can be formed from H2NNO with a low barrier over Cu-OOH-Cu complexes, which are proposed intermediates in the catalytic cycle for NH3-SCR over Cu-CHA. This finding provides an explanation for the experimentally observed low-temperature N2O formation and the relation between Cu loading and N2O formation. The proposed mechanisms open up strategies to enhance the selectivity to N2 during NH3-SCR.

N2O

DFT

Cu-CHA

NH3-SCR

Författare

Yingxin Feng

Chalmers, Fysik, Kemisk fysik

Ton V. W. Janssens

Umicore

Peter N. R. Vennestrom

Umicore

Jonas Jansson

Volvo Group

Magnus Skoglundh

Chalmers, Kemi och kemiteknik, Tillämpad kemi, Polymerteknologi

Henrik Grönbeck

Chalmers, Fysik, Kemisk fysik

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 125 8 4595-4601

Ämneskategorier

Oorganisk kemi

Fysikalisk kemi

Annan fysik

Drivkrafter

Hållbar utveckling

Fundament

Grundläggande vetenskaper

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1021/acs.jpcc.0c11008

Mer information

Senast uppdaterat

2021-04-13