Chemical Kinetic Method for Active-Site Quantification in Fe-N-C Catalysts and Correlation with Molecular Probe and Spectroscopic Site-Counting Methods
Source: BAM
Atomically-dispersed catalysts, sometimes referred to as Single Atom Catalysts, are a promising class of materials to substitute precious-group metal catalysts, or to reduce the required metal loading, in societally important electrocatalytic reaction and increasingly also for thermocatalytical reactions. The catalytically active center of such materials is a single atom or ion bound to specific binding sites of the catalysts. Knowledge about the specific activity of certain catalyst compositions or the intrinsic catalytic activity of specific catalytic sites is fundamental to the optimization of such catalysts, but also for the comparison with conventional catalysts. To date the accurate quantification of the number/concentration of accessible catalytically active sites however, is still matter of scientific research. In this publication, a critical overview of currently used techniques is given along with the introduction of a new, chemically kinetic method. Furthermore, state-of-the-art catalysts of leading groups in the field including Division 3.6 at BAM are used for the comparison of the new technique with the established techniques of CO pulsed chemisorption, Mössbauer spectroscopy, and electrochemical reductive stripping of NO. The article gives a useful overview of the state-of-the-art techniques that should be used and further motivates the continuation of research with the goal to establish a single metrological norm for the new class of catalysts.
Chemical Kinetic Method for Active-Site Quantification in Fe-N-C Catalysts and Correlation with Molecular Probe and Spectroscopic Site-Counting Methods
Jason S. Bates, Jesse J. Martinez, Melissa N. Hall, Abdulhadi A. Al-Omari, Eamonn Murphy, Yachao Zeng, Fang Luo, Mathias Primbs, Davide Menga, Nicolas Bibent, Moulay Tahar Sougrati, Friedrich E. Wagner, Plamen Atanassov, Gang Wu, Peter Strasser, Tim-Patrick Fellinger, Frédéric Jaouen, Thatcher W. Root, and Shannon S. Stahl
Journal of the American Chemical Society 2023