Premixed gases are fed through a honeycomb towards a heated catalytic substrate. In situ Raman spectroscopy is used to measure species concentrations along the centerline. Substrate and injector head can be manually translated to allow measurements at 0.5–19.5 mm from the catalytic substrate.

In recent years, several advanced hydrogen production applications have emerged that exploit the product selectivity and ignition-control characteristics of fuel-rich catalytic combustion. Several of these new methods rely on the complex chemistry associated with partial oxidation over supported nobel metal catalysts. Most notable are new autothermal processes for generating synthesis gas from methane or dehydrogenating ethane to ethylene in short-contact-time reactors (SCTR). Although, it is common for catalytic metals such as platinum, palladium, and rhodium to be used near stoichiometry for exhaust-gas aftertreatment or as initiators of fuel-lean combustion in heat and power generation, operating these materials under fuel-rich, reducing environments can have pronounced effects on reactivity, because the extent of surface oxidation ultimately determines the rate of C–H bond activation.

A new experimental approach uses pulsed Raman spectroscopy to measure the concentration of hydrocarbons along the centerline of the reactor with the catalytic surface at 800–1250°C. The method permits the direct comparison of the measured reactivity with that predicted by the CHEMKIN^™ SPIN stagnation-flow code when combined with recently developed partial-oxidation elementary reaction mechanisms.

The catalyst can vary from simple metal foils to discs of more realistic formulations such as a metal oxide system. Current work is focused on a new partial-oxidation system based on hexaaluminates that was developed at Sandia.

The experimental results are interpreted by examining the competitive adsorption between CH₄ and O₂. This research has identified the sticking coefficient for dissociative adsorption of CH₄ as a highly uncertain parameter in the reaction mechanisms. Its modification allows the models to capture the experimentally observed changes in consumption of CH₄ and the selectivity to H₂ and CO with increasing temperature.