Nanoplasmonic probes of catalytic reactions.

Optical probes of heterogeneous catalytic reactions can be valuable tools for optimization and process control because they can operate under realistic conditions, but often probes lack sensitivity. We have developed a plasmonic sensing method for such reactions based on arrays of nanofabricated gold disks, covered by a thin (approximately 10 nanometer) coating (catalyst support) on which the catalyst nanoparticles are deposited. The sensing particles monitor changes in surface coverage of reactants during catalytic reaction through peak shifts in the optical extinction spectrum. Sensitivities to below 10(-3) monolayers are estimated. The capacity of the method is demonstrated for three catalytic reactions, CO and H2 oxidation on Pt, and NO(x) conversion to N2 on Pt/BaO.