In situ Raman spectroscopy. A powerful tool for studies in selective catalytic oxidation

In this review, some of advantages and problems of in situ Raman spectroscopy are briefly mentioned. The applications of laser Raman spectroscopy LRS to the study of catalysts used for selective oxidation is then reviewed based on published work on catalysis by molybdate and VPO catalysts. Investigations of synergy effects have also been carried and results on O-18-exchange and reoxidation of SbOx/MoO3 physical mixtures are reported. Spillover oxygen - if present - could not be detected. Peroxide species have been detected on working methane coupling catalysts at temperatures up to 1070 K and they have been identified as centers for the activation of methane. Model studies were performed of the methanol oxidation to formaldehyde on Ag single crystal surface at temperatures up to 1170 K. Surface enhancement permitted the detection of a strongly chemisorbed surface oxygen species O-gamma, which was in equilibrium with a bulk species O-beta and which was identified as the reactive species involved in the methanol oxidation.