Single crystals as model catalysts

Recent work has demonstrated the special advantages of meshing in a single apparatus kinetic measurements at process‐like conditions with modern surface analytical techniques for fundamental catalytic studies. These data have shown that low surface area monolithic materials can be used successfully to model certain catalytic systems. Virtually identical kinetic parameters have been found for the methanation reaction over single crystals of nickel and ruthenium as have been measured for high surface area nickel and ruthenium process catalysts. Surface probes have allowed the methanation reaction to be mechanistically dissected, in that the kinetics associated with the two major reaction steps have been individually measured. Using surface probes to monitor quantity and ordering of the impurity atoms, a correlation has been found between the electronegativity of the impurity atom and its catalytic poisoning ability. Electronic effects, as opposed to site blocking, are shown to dominate.