We have unlocked Surface Enhanced Raman Spectroscopy (SERS) as an analytical technique in probing catalytic systems by investigating metal oxide catalysts that are supported on alumina. To accomplish this, robust SERS substrates were generated by depositing an ultra-thin coating of alumina on top of silver nanowires (NWs) via atomic layer deposition (ALD).  The first of these in situ studies was conducted by analyzing the effects of heating a solid acid, phosphotungstic acid (PTA), on the alumina surface in either an oxygen or hydrogen environment at temperatures up to 400 oC.  Interestingly, the distance-dependent decay of the enhancement factor of the SERS signal from the underlying NWs allowed us to probe with enhanced detail the interfacial region between the PTA and the alumina surface.  The ability to analyze the area closest to the alumina surface was further confirmed by assembling vanadia onto the substrate, and monitoring the intensity differences between the V-O-Al and outer V=O bonds. Further, we also monitored adsorbate-interface interactions between acetonitrile and the various thicknesses of the ALD deposited alumina layers; and examined the adsorption/desorption at high temperatures of pyridine on the acidic sites of a solid acid.

Unlocking surface enhanced Raman spectroscopy for the analysis of catalytic systems and interfaces

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.