This paper starts from the consideration that SSITKA method (steady state isotopic transient kinetic analysis – Happel, Benett, Biolen) gives us enough information regarding kinetics and less information regarding catalyst surface. A modified variant of this method, for obtaining in principle information about catalyst surface was developed by the authors.
The experiment was focused on Ni catalysts on the oxide support, with the main goal to verify if the interface metal-support and even support has important role in catalyse (point out of “spill-over” process). Due the fact that the studied catalysers are active in reactions with H2 participation, the isotopic exchange reaction H/D is proper for study.
The paper presents measurements for isotopic exchange between H2 and D2 recording the evolution of adsorbed species from time 0 till steady state obtaining. Taking into account that between species adsorbed on metal and those existed on support there is a dynamic equilibrium given by the spill-over effect, employment of two isotopes of the same element there is the only one direct method for making evident the migrations which get on. Using two stable isotopes there is possible to make evident the modification of the support surface during catalytic process.
In experiment were used Ni/ZnO, Ni/TiO2, Ni/SiO2, Ni/MgO, Ni/ZrO2, Ni/Cr2O3, Ni/Al2O3. Catalysts made with co-precipitation method.
The paper explains all details of experiment and curves obtained, based on mathematical model (extended and simplified). Except of qualitative explanations based on spill-over phenomenon, there are given also quantitative considerations based on the transformation of MS diagrams in kinetic quantitative curves. The used equations are presented.