Influence of the surrounding atmosphere upon the catalytic performances of three-way catalysts Original Research Article

The adaptation of the catalytic surface to the gas phase may induce modifications of the atomic arrangement. The interaction between the gas phase composition and three-way catalyst type were investigated both by in situ EXAFS experiments and in a laboratory reactor. In both cases, experimental conditions simulating the exhaust from a catalytic converter were reproduced. Activity measurements in an oscillating feed of CO, NO, C3H5 and O2 revealed that application of a traditional kinetic study was not possible owing to the transformation of the active site during the course of the reaction. The occurrence of a redox process involving rhodium when using Pt—Rh/Al2O3 was observed as well as that of Pt—Rh alloy formation.