divided into a reduction of the catalyst by NO + NH3
O2 or by NO2
and an oxidation either by NO + . N2
and water are produced in
both the oxidation and reduction steps. Together these constitute a complete catalytic cycle. Every step of the cycle uses only common stable molecules, eliminating the issues of charged or ‘half molecules’ present in other suggestions.
“Catalysts do not enter their active state until you
expose the catalyst system to the conditions of the reaction”
Since finding a solution to the catalytic
cycle, Mossin and her PhD student Anita Godiksen have been performing in situ EPR spectroscopy to back up their work.
The catalytic cycle
“Catalysts do not enter their active state until you expose the catalyst system to the conditions of the reaction,” says Mossin. “It is therefore not good enough to investigate these materials with ex situ methods – you need to look at them under operando conditions.” EPR spectroscopy is
undemanding instrument-wise
compared to other advanced spectroscopic methods, making it particularly suited for in situ and operando investigations for systems containing EPR active elements. Collaborators from the University of Turin have provided extra experimental evidence in the form of in situ X-ray absorption spectroscopy and Fourier transform infrared spectroscopy. With the framework for the catalysis
mechanism now in place, Mossin will spend the remainder of the
three-year
project confirming the individual steps, as well as looking for deactivation mechanism of the catalyst system. “Knowing what makes a catalyst work and what stops it working is useful,” she explains. “Catalysts must often be designed to fit specific criteria such as lifespan and stability, so the more knowledge you have about how they work, the more you can tweak them to work more efficiently in certain conditions.”
★
AT A GLANCE Project Information
Project Title: Spectroscopic investigations of copper substituted zeolites for catalysis
Project Objective: To use and develop in-situ and operando electron paramagnetic resonance spectroscopy to characterize and quantify catalytically active centers in copper substituted zeolite materials. To use the knowledge to elucidate the catalytic cycle.
Project Duration and Timing: 3 years, October 2013 to September 2016
Project Funding: The project is sponsored by the Danish Council for Independent Research, Technology and Production, DFF – 1335-00175. Equipment is supported by the Carlsberg Foundation.
Project Partners: Haldor Topsøe A/S
MAIN CONTACT
Susanne Mossin After completing a PhD in inorganic chemistry from the University of Copenhagen in 2006 with Høgni Weihe and post- doctoral work with Prof. Karsten Meyer (FAU Erlangen-Nuremberg) Susanne Mossin joined the faculty at Department of Chemistry, DTU in 2010.
Contact: Tel: +45 45252391 Email:
slmo@kemi.dtu.dk Web:
www.csc.kemi.dtu.dk
www.projectsmagazine.eu.com
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