UV-Vis and Photoluminescence Spectroscopy to Understand the Coordination of Cu Cations in the Zeolite SSZ-13

Florian Göltl, Sabrina Conrad, Patrick Wolf, Philipp Müller, Alyssa M. Love, Samuel P. Burt, Jamie N. Wheeler, Robert J. Hamers, Kerstin Hummer, Georg Kresse, Manos Mavrikakis, Ive Hermans

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

The Cu-exchanged zeolite SSZ-13 is a highly active material in the selective catalytic reduction of nitrogen oxides and the conversion of methane to methanol. In this material, a distribution of active sites is present and its characterization is a long standing challenge. In this contribution, we combine molecular dynamics simulations and high-level first principles calculations to obtain accurate phase diagrams, photoabsorption, and photoluminescence spectra of CuI sites in SSZ-13 and compare them to specifically designed experimental measurements. We start our analysis by using molecular dynamics and random phase approximation calculations to calculate phase diagrams for Cu anchored in extra-framework and silanol defect sites. Subsequently, we combine molecular dynamics and a time-dependent hybrid Hartree-Fock like linear response scheme to calculate photoabsorption and photoluminescence spectra. We determine that at low temperatures CuI is coordinated to multiple H2O molecules. At elevated temperatures and low pressures, all H2O molecules desorb and CuI migrates to defect sites, as long as defects are present in the material. Theoretically predicted and experimentally measured optical spectra are in excellent agreement. Additionally, we discuss the impact of defects on the observed luminescence spectra. We expect that the methods developed here will be used to better understand the distribution of Cu sites in the zeolite SSZ-13 under various conditions. Further, this work sheds light on a potential role of defects in the coordination of CuI in deNOx-SCR in aged catalysts and helps with understanding luminescence spectra of transition-metal sites in zeolites.

Original languageEnglish (US)
Pages (from-to)9582-9592
Number of pages11
JournalChemistry of Materials
Volume31
Issue number23
DOIs
StatePublished - Dec 10 2019
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Fingerprint

Dive into the research topics of 'UV-Vis and Photoluminescence Spectroscopy to Understand the Coordination of Cu Cations in the Zeolite SSZ-13'. Together they form a unique fingerprint.

Cite this