Structure-sensitivity of ammonia synthesis reaction

Whether on iron catalysts or ruthenium catalysts, ammonia synthesis reaction has been proved to be a structure-sensitive reaction, and has been discussed in literature. Ertl and Spencer made tremendous contributions to the final determination of reaction mechanism and structure-sensitivity. 

Crystal face Reaction rate/ (mol NH3-cm -s ) Crystal face Reaction rate/ (mol NH3-cm -s ) 

T/K yn chem isot (Njlv/Pa T/K syn chem isot (Nalv/Pa 

Note 0syn, 0cbem 2 nd isot correspond respectively to synthesis, chemisorption and the adsorption isotherm of R umkin-Temkin. 

Columns 2 and 3 in Tabie 2.11 show the values of 9, at equal rates of ammonia synthesis and chemisorption, respectively. The extreme agreement at various temperatures confirms the view that chemisorption of dinitrogen is the rate determining step. 

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