Heterogeneous most abundant surface intermediate

The concept of a predominant cycle member was first introduced in heterogeneous catalysis by Boudart [42], who coined the term "most abundant surface intermediate," abbreviated masi (see Section 8.10). 

The concept of a most abundant catalyst-containing species (macs in this book) was originally introduced by Boudart for heterogeneous catalysis under the name of masi, for "most abundant surface intermediate" [42]. 

The surface coverages by reaction intermediates could also be calculated by the model. It was found that N- is by far the most abundant surface intermediate under typical synthesis conditions, but the sum of the coverages by other intermediates is also larger than the coverage by free sites. This fact is seen by the authors to be the cause for the complicated kinetics deduced by Ozaki et al. [56], rather than adsorbate-adsorbate interaction or surface heterogeneity. 

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