Laser Raman spectroscopy - a powerful tool for in situ studies of catalytic materials

Advantages and limitations of laser Raman spectroscopy (LRS) as an in situ vibrational spectroscopy for the study of catalytic materials and surfaces under working conditions are discussed. Measurements can be carried out at temperatures as high as 1200 K in controlled atmospheres. Modern instrument ation permits time resolutions in the sub-second regime for materials with high Raman cross sections. Transient studies are thus possible. Several exa mples are presented of in situ LRS studies including the phase analysis of bismuth molybdate and VPO oxidation catalysts, synergy effects and oxygen e xchange in Sb2O3/MoO3 oxide mixtures, intermediates in oxidative coupling o f methane, NO decomposition on Ba/MgO catalysts, and transient SERS studies of partial oxidation of methanol on Ag single crystal surfaces and of the reduction of oxide overlayers on electrodeposited Rh layers.