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Microfluidic reactors with in situ spectroscopy have enabled many new directions of research over the last two decades. The miniature nature of these systems enables several key advantages in heterogeneous catalysis, which includes the reaction surface or interface accessible to spectroscopic equipment making the discovery of new catalytic materials possible. Devices fabricated with materials that are transparent to electromagnetic radiation enable in situ and in operando spectroscopy such as Raman, UV-Vis, and IR directly at the point of the reaction, and thus high fidelity, transient information on the reaction chemistry is available. Innovative designs with NMR, electrochemical impedance spectroscopy, x-ray techniques, or terahertz imaging have also advanced the field of heterogeneous catalysis. These methods have been successfully engineered to make major breakthroughs in the design of catalytic materials for important classes of chemical reactions. In this review, the authors provide an overview of recent advances in the design of microreactors with in situ spectroscopy for the study of heterogeneous catalysis to raise awareness among the vacuum science community on techniques, tools, existing challenges, and emerging trends and opportunities.
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Towards bridging the structure gap in heterogeneous catalysis: the impact of defects in dissociative chemisorption of methane on Ir surfaces
A quantitative understanding of the role played by defect sites in heterogeneous catalysis is of great importance in designing new and more effective catalysts. In this work, we report a detailed dynamic study of a key step in methane steam reforming under experimentally relevant conditions on a new high-dimensional potential energy surface determined from first principles data with the aid of machine learning, with which the interactions of CH 4 with both the flat Ir(111) and stepped Ir(332) surfaces are described. In particular, we argue based on our simulations that the experimentally observed “negatively activated” dissociative chemisorption of methane on Ir surfaces could be due to a combined effect of defects and high substrate temperature, which lowers the reaction barrier relative to that on terraces. Furthermore, a model based on dynamic information of trapping and reaction channels is proposed, which allows a quantitative prediction of the initial sticking probability for different defect densities, thus helping to close the so-called structure gap in heterogeneous catalysis.
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- Award ID(s):
- 1951328
- PAR ID:
- 10233035
- Date Published:
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 23
- Issue:
- 7
- ISSN:
- 1463-9076
- Page Range / eLocation ID:
- 4376 to 4385
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D0CP06535H
