Research at LRI
Innovation in Catalysis for Energy and The Environment
Contracted Research and Development Studies
The novelty of the TAP characterization technique is that it is generally applicable to study a wide range of catalyst systems and gas/solid interface technologies such as chemical sensors and advanced coatings.
Our facility employs a group of highly specialized scientists and engineers that can most efficiently deliver research analysis tailored to a customer’s individual needs. In a central location we have concentrated a conglomerate of ‘high capital’, state-of-the-art catalyst characterization instrumentation but more importantly, we have the specialized researchers who can most effectively extract meaningful data and integrate it with results from our other techniques.
TAP (Temporal Analysis of Products)
The TAP-3 Reactor System owned and operated by the Langmuir Research Institute was recently donated from Mithra Technologies. The TAP experiment is a unique transient experiment that offers a detailed kinetic description of the intrinsic processes occurring on the catalyst surface.
A schematic for describing a basic TAP experiment is shown in the drawing below.
The observed characteristic in a TAP experiment is the time dependent gas flow F(t) [moles/s] or [molec/s] that escapes from the exit of the microreactor. The flow dependencies also have integral characteristics that are the moments of the "flow-time" dependencies. The unique design of a TAP Knudsen pulse response experiment gives rise to a number of unique features, which make this experiment a particularly powerful tool for studying reactions on complex solids.
First, because there is no restriction on the form of the solid sample, complex materials with multiscaler structures including complex pore structures can be readily studied.
Second, because the introduction of reactant molecules involves a simple "on-off" process the mathematical model, a set of partial differential equations, used to describe transport through the reactor has very simple initial and boundary conditions.
Third, because the experiment is performed in the Knudsen flow regime, the diffusion of individual reactants does not change during a reaction. In a TAP Knudsen pulse-response experiment, the diffusion process does not act as a disturbing factor, but operates as a "time standard" against which events in a complex chemical transformation can be measured. In fact, TAP experiments provide important information on transport as well as kinetics.
Fourth, because the number of gas molecules in the inlet pulse can be adjusted to make the number of "reactant molecules" much smaller than the total number of active species in the bed of solid particles, the composition of the sample does not change significantly during a pulse.
Fifth, because the experiment is a high-speed transient response experiment different kinetic processes can be distinguished, and the sequence of a complex mechanism can be unraveled. Reaction intermediates difficult to detect in steady-state experiments can often be easily observed in TAP experiments.
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