Determining the reaction mechanism is often integral to developing catalytic materials with enhanced performance. By linking in situ/operando catalyst characterization and evaluation through isotopic labeling experiments, chemical transformations over catalyst surfaces can be tracked in real-time, leading to the development of structure-function relationships.
The Steady State Isotopic-Transient Kinetic Analysis (SSITKA) capability at the National Renewable Energy Laboratory allows for catalyst surface chemistry to be studied under steady state reaction conditions. This is accomplished through analysis and modeling of the transient response in the effluent stream following the isobaric and isothermal isotope switch in the reactant feed (i.e., 12CH3CH2OH to 13CH3CH2OH). Abundance and residence times of intermediate species, rate constants, density of active sites, turnover frequencies, and mechanistic pathways can all be determined via SSITKA.
The National Stable Isotope Resource at Los Alamos National Laboratory advances the application of isotopic labeling experiments by providing 2H, 13C, 15N, 17O, 18O, 33S, 34S, and 77Se labeling for amino acids, synthons, nucleic acids, and carbohydrates. Moreover, isotopically enriched intermediates can be synthesized by introducing isotopes at specific positions, allowing us to follow a reaction at one or more specific positions on the molecule and track the conversion of functional groups.
Argonne National Laboratory
Lawrence Berkeley National Laboratory
Los Alamos National Laboratory
National Renewable Energy Laboratory
Oak Ridge National Laboratory
Pacific Northwest National Laboratory