Structure-reactivity relations for catalytic surfaces modified with self-assembled monolayers
EMSL Project ID
44490
Abstract
This Rapid Access proposal is aimed at conducting proof-of-concept studies to explore catalytic chemistry at model interfaces that are of great interest for improving understanding and developing new catalyst designs in heterogeneous catalysis. Previous work by the researchers on this proposal has demonstrated that self-assembled monolayers (SAMs) of thiolates can be deposited on surfaces to dramatically alter the selectivity of reactions catalyzed by supported metals while still achieving industrially relevant reaction rates. Studies of catalysts modified by SAMs have a large potential for broad impact, since SAMs represent a highly tunable platform for modifying the interface between the solid catalyst and a reacting fluid. In the proposed work, the EMSL capabilities for high pressure catalysis using well-characterized model materials will be used to explore the detailed mechanism by which SAMs modify reactivity and selectivity for key probe hydrogenation reactions. The facilities at EMSL offer unique capabilities that are otherwise inaccessible to the PI, and offer the potential to provide direct connections between the structure of the SAM-modified surface and observed trends in reactivity and selectivity.In the proof-of-concept studies proposed here, a Pd(111) surface will be used as a catalyst for the hydrogenation of the probe molecules 1-epoxy-3-butene and acetylene. A suite of characterization techniques will be employed to characterize the surface before, during, and after exposure to reaction conditions. The Pd(111) crystal will subsequently be removed from the system and coated with a self-assembled monolayer of the alkanethiol C18H37SH, as done previously by the PI's group. The SAM-coated surface will then be investigated in an analogous fashion to the uncoated surface to explore its effects on the catalytic reactions and surface intermediates.
This proof-of-concept investigation will open up opportunities for further, more in-depth investigations of structure-property relations for SAM modified catalysts. For example, it will be possible to characterize in detail the structure sensitivity of the selectivity effects of SAMs, the role of SAM coverage, and the role of interactions between neighboring SAMs and reactive adsorbates.
Project Details
Project type
Exploratory Research
Start Date
2011-05-16
End Date
2012-05-20
Status
Closed
Released Data Link
Team
Principal Investigator